org.apache.commons.lang

Class StringUtils

public class StringUtils extends Object

Operations on {@link java.lang.String} that are null safe.

The StringUtils class defines certain words related to String handling.

StringUtils handles null input Strings quietly. That is to say that a null input will return null. Where a boolean or int is being returned details vary by method.

A side effect of the null handling is that a NullPointerException should be considered a bug in StringUtils (except for deprecated methods).

Methods in this class give sample code to explain their operation. The symbol * is used to indicate any input including null.

Since: 1.0

Version: $Id: StringUtils.java 161243 2005-04-14 04:30:28Z ggregory $

Author: Apache Jakarta Turbine GenerationJavaCore Jon S. Stevens Daniel Rall Greg Coladonato Henri Yandell Ed Korthof Rand McNeely Stephen Colebourne Fredrik Westermarck Holger Krauth Alexander Day Chaffee Henning P. Schmiedehausen Arun Mammen Thomas Gary Gregory Phil Steitz Al Chou Michael Davey

See Also: java.lang.String

Field Summary
static StringEMPTY
The empty String "".
static intINDEX_NOT_FOUND
Represents a failed index search.
Constructor Summary
StringUtils()

StringUtils instances should NOT be constructed in standard programming.

Method Summary
static Stringabbreviate(String str, int maxWidth)

Abbreviates a String using ellipses.

static Stringabbreviate(String str, int offset, int maxWidth)

Abbreviates a String using ellipses.

static Stringcapitalise(String str)

Capitalizes a String changing the first letter to title case as per {@link Character#toTitleCase(char)}.

static StringcapitaliseAllWords(String str)

Capitalizes all the whitespace separated words in a String.

static Stringcapitalize(String str)

Capitalizes a String changing the first letter to title case as per {@link Character#toTitleCase(char)}.

static Stringcenter(String str, int size)

Centers a String in a larger String of size size using the space character (' ').

If the size is less than the String length, the String is returned.

static Stringcenter(String str, int size, char padChar)

Centers a String in a larger String of size size.

static Stringcenter(String str, int size, String padStr)

Centers a String in a larger String of size size.

static Stringchomp(String str)

Removes one newline from end of a String if it's there, otherwise leave it alone.

static Stringchomp(String str, String separator)

Removes separator from the end of str if it's there, otherwise leave it alone.

NOTE: This method changed in version 2.0.

static StringchompLast(String str)

Remove any "\n" if and only if it is at the end of the supplied String.

static StringchompLast(String str, String sep)

Remove a value if and only if the String ends with that value.

static Stringchop(String str)

Remove the last character from a String.

If the String ends in \r\n, then remove both of them.

 StringUtils.chop(null)          = null
 StringUtils.chop("")            = ""
 StringUtils.chop("abc \r")      = "abc "
 StringUtils.chop("abc\n")       = "abc"
 StringUtils.chop("abc\r\n")     = "abc"
 StringUtils.chop("abc")         = "ab"
 StringUtils.chop("abc\nabc")    = "abc\nab"
 StringUtils.chop("a")           = ""
 StringUtils.chop("\r")          = ""
 StringUtils.chop("\n")          = ""
 StringUtils.chop("\r\n")        = ""
 
static StringchopNewline(String str)

Removes \n from end of a String if it's there.

static Stringclean(String str)

Removes control characters (char <= 32) from both ends of this String, handling null by returning an empty String ("").

 StringUtils.clean(null)          = ""
 StringUtils.clean("")            = ""
 StringUtils.clean("abc")         = "abc"
 StringUtils.clean("    abc    ") = "abc"
 StringUtils.clean("     ")       = ""
 
static Stringconcatenate(Object[] array)

Concatenates elements of an array into a single String.

static booleancontains(String str, char searchChar)

Checks if String contains a search character, handling null.

static booleancontains(String str, String searchStr)

Checks if String contains a search String, handling null.

static booleancontainsNone(String str, char[] invalidChars)

Checks that the String does not contain certain characters.

A null String will return true.

static booleancontainsNone(String str, String invalidChars)

Checks that the String does not contain certain characters.

A null String will return true.

static booleancontainsOnly(String str, char[] valid)

Checks if the String contains only certain characters.

A null String will return false.

static booleancontainsOnly(String str, String validChars)

Checks if the String contains only certain characters.

A null String will return false.

static intcountMatches(String str, String sub)

Counts how many times the substring appears in the larger String.

A null or empty ("") String input returns 0.

 StringUtils.countMatches(null, *)       = 0
 StringUtils.countMatches("", *)         = 0
 StringUtils.countMatches("abba", null)  = 0
 StringUtils.countMatches("abba", "")    = 0
 StringUtils.countMatches("abba", "a")   = 2
 StringUtils.countMatches("abba", "ab")  = 1
 StringUtils.countMatches("abba", "xxx") = 0
 
static StringdefaultIfEmpty(String str, String defaultStr)

Returns either the passed in String, or if the String is empty or null, the value of defaultStr.

 StringUtils.defaultIfEmpty(null, "NULL")  = "NULL"
 StringUtils.defaultIfEmpty("", "NULL")    = "NULL"
 StringUtils.defaultIfEmpty("bat", "NULL") = "bat"
 
static StringdefaultString(String str)

Returns either the passed in String, or if the String is null, an empty String ("").

 StringUtils.defaultString(null)  = ""
 StringUtils.defaultString("")    = ""
 StringUtils.defaultString("bat") = "bat"
 
static StringdefaultString(String str, String defaultStr)

Returns either the passed in String, or if the String is null, the value of defaultStr.

 StringUtils.defaultString(null, "NULL")  = "NULL"
 StringUtils.defaultString("", "NULL")    = ""
 StringUtils.defaultString("bat", "NULL") = "bat"
 
static StringdeleteSpaces(String str)

Deletes all 'space' characters from a String as defined by {@link Character#isSpace(char)}.

This is the only StringUtils method that uses the isSpace definition.

static StringdeleteWhitespace(String str)

Deletes all whitespaces from a String as defined by {@link Character#isWhitespace(char)}.

 StringUtils.deleteWhitespace(null)         = null
 StringUtils.deleteWhitespace("")           = ""
 StringUtils.deleteWhitespace("abc")        = "abc"
 StringUtils.deleteWhitespace("   ab  c  ") = "abc"
 
static Stringdifference(String str1, String str2)

Compares two Strings, and returns the portion where they differ.

static booleanequals(String str1, String str2)

Compares two Strings, returning true if they are equal.

nulls are handled without exceptions.

static booleanequalsIgnoreCase(String str1, String str2)

Compares two Strings, returning true if they are equal ignoring the case.

nulls are handled without exceptions.

static Stringescape(String str)

Escapes any values it finds into their String form.

So a tab becomes the characters '\\' and 't'.

As of Lang 2.0, this calls {@link StringEscapeUtils#escapeJava(String)} behind the scenes.

static StringgetChomp(String str, String sep)

Remove everything and return the last value of a supplied String, and everything after it from a String.

static intgetLevenshteinDistance(String s, String t)

Find the Levenshtein distance between two Strings.

This is the number of changes needed to change one String into another, where each change is a single character modification (deletion, insertion or substitution).

This implementation of the Levenshtein distance algorithm is from http://www.merriampark.com/ld.htm

 StringUtils.getLevenshteinDistance(null, *)             = IllegalArgumentException
 StringUtils.getLevenshteinDistance(*, null)             = IllegalArgumentException
 StringUtils.getLevenshteinDistance("","")               = 0
 StringUtils.getLevenshteinDistance("","a")              = 1
 StringUtils.getLevenshteinDistance("aaapppp", "")       = 7
 StringUtils.getLevenshteinDistance("frog", "fog")       = 1
 StringUtils.getLevenshteinDistance("fly", "ant")        = 3
 StringUtils.getLevenshteinDistance("elephant", "hippo") = 7
 StringUtils.getLevenshteinDistance("hippo", "elephant") = 7
 StringUtils.getLevenshteinDistance("hippo", "zzzzzzzz") = 8
 StringUtils.getLevenshteinDistance("hello", "hallo")    = 1
 
static StringgetNestedString(String str, String tag)

Gets the String that is nested in between two instances of the same String.

A null input String returns null.

static StringgetNestedString(String str, String open, String close)

Gets the String that is nested in between two Strings.

static StringgetPrechomp(String str, String sep)

Remove and return everything before the first value of a supplied String from another String.

static intindexOf(String str, char searchChar)

Finds the first index within a String, handling null.

static intindexOf(String str, char searchChar, int startPos)

Finds the first index within a String from a start position, handling null.

static intindexOf(String str, String searchStr)

Finds the first index within a String, handling null.

static intindexOf(String str, String searchStr, int startPos)

Finds the first index within a String, handling null.

static intindexOfAny(String str, char[] searchChars)

Search a String to find the first index of any character in the given set of characters.

A null String will return -1.

static intindexOfAny(String str, String searchChars)

Search a String to find the first index of any character in the given set of characters.

A null String will return -1.

static intindexOfAny(String str, String[] searchStrs)

Find the first index of any of a set of potential substrings.

A null String will return -1.

static intindexOfAnyBut(String str, char[] searchChars)

Search a String to find the first index of any character not in the given set of characters.

A null String will return -1.

static intindexOfAnyBut(String str, String searchChars)

Search a String to find the first index of any character not in the given set of characters.

A null String will return -1.

static intindexOfDifference(String str1, String str2)

Compares two Strings, and returns the index at which the Strings begin to differ.

For example, indexOfDifference("i am a machine", "i am a robot") -> 7

 StringUtils.indexOfDifference(null, null) = -1
 StringUtils.indexOfDifference("", "") = -1
 StringUtils.indexOfDifference("", "abc") = 0
 StringUtils.indexOfDifference("abc", "") = 0
 StringUtils.indexOfDifference("abc", "abc") = -1
 StringUtils.indexOfDifference("ab", "abxyz") = 2
 StringUtils.indexOfDifference("abcde", "abxyz") = 2
 StringUtils.indexOfDifference("abcde", "xyz") = 0
 
static booleanisAlpha(String str)

Checks if the String contains only unicode letters.

null will return false.

static booleanisAlphanumeric(String str)

Checks if the String contains only unicode letters or digits.

null will return false.

static booleanisAlphanumericSpace(String str)

Checks if the String contains only unicode letters, digits or space (' ').

null will return false.

static booleanisAlphaSpace(String str)

Checks if the String contains only unicode letters and space (' ').

null will return false An empty String ("") will return true.

 StringUtils.isAlphaSpace(null)   = false
 StringUtils.isAlphaSpace("")     = true
 StringUtils.isAlphaSpace("  ")   = true
 StringUtils.isAlphaSpace("abc")  = true
 StringUtils.isAlphaSpace("ab c") = true
 StringUtils.isAlphaSpace("ab2c") = false
 StringUtils.isAlphaSpace("ab-c") = false
 
static booleanisAsciiPrintable(String str)

Checks if the string contains only ASCII printable characters.

null will return false.

static booleanisBlank(String str)

Checks if a String is whitespace, empty ("") or null.

 StringUtils.isBlank(null)      = true
 StringUtils.isBlank("")        = true
 StringUtils.isBlank(" ")       = true
 StringUtils.isBlank("bob")     = false
 StringUtils.isBlank("  bob  ") = false
 
static booleanisEmpty(String str)

Checks if a String is empty ("") or null.

 StringUtils.isEmpty(null)      = true
 StringUtils.isEmpty("")        = true
 StringUtils.isEmpty(" ")       = false
 StringUtils.isEmpty("bob")     = false
 StringUtils.isEmpty("  bob  ") = false
 

NOTE: This method changed in Lang version 2.0.

static booleanisNotBlank(String str)

Checks if a String is not empty (""), not null and not whitespace only.

 StringUtils.isNotBlank(null)      = false
 StringUtils.isNotBlank("")        = false
 StringUtils.isNotBlank(" ")       = false
 StringUtils.isNotBlank("bob")     = true
 StringUtils.isNotBlank("  bob  ") = true
 
static booleanisNotEmpty(String str)

Checks if a String is not empty ("") and not null.

 StringUtils.isNotEmpty(null)      = false
 StringUtils.isNotEmpty("")        = false
 StringUtils.isNotEmpty(" ")       = true
 StringUtils.isNotEmpty("bob")     = true
 StringUtils.isNotEmpty("  bob  ") = true
 
static booleanisNumeric(String str)

Checks if the String contains only unicode digits.

static booleanisNumericSpace(String str)

Checks if the String contains only unicode digits or space (' ').

static booleanisWhitespace(String str)

Checks if the String contains only whitespace.

null will return false.

static Stringjoin(Object[] array)

Joins the elements of the provided array into a single String containing the provided list of elements.

No separator is added to the joined String.

static Stringjoin(Object[] array, char separator)

Joins the elements of the provided array into a single String containing the provided list of elements.

No delimiter is added before or after the list.

static Stringjoin(Object[] array, String separator)

Joins the elements of the provided array into a single String containing the provided list of elements.

No delimiter is added before or after the list.

static Stringjoin(Iterator iterator, char separator)

Joins the elements of the provided Iterator into a single String containing the provided elements.

No delimiter is added before or after the list.

static Stringjoin(Iterator iterator, String separator)

Joins the elements of the provided Iterator into a single String containing the provided elements.

No delimiter is added before or after the list.

static intlastIndexOf(String str, char searchChar)

Finds the last index within a String, handling null.

static intlastIndexOf(String str, char searchChar, int startPos)

Finds the last index within a String from a start position, handling null.

static intlastIndexOf(String str, String searchStr)

Finds the last index within a String, handling null.

static intlastIndexOf(String str, String searchStr, int startPos)

Finds the first index within a String, handling null.

static intlastIndexOfAny(String str, String[] searchStrs)

Find the latest index of any of a set of potential substrings.

A null String will return -1.

static Stringleft(String str, int len)

Gets the leftmost len characters of a String.

If len characters are not available, or the String is null, the String will be returned without an exception.

static StringleftPad(String str, int size)

Left pad a String with spaces (' ').

The String is padded to the size of size.

 StringUtils.leftPad(null, *)   = null
 StringUtils.leftPad("", 3)     = "   "
 StringUtils.leftPad("bat", 3)  = "bat"
 StringUtils.leftPad("bat", 5)  = "  bat"
 StringUtils.leftPad("bat", 1)  = "bat"
 StringUtils.leftPad("bat", -1) = "bat"
 
static StringleftPad(String str, int size, char padChar)

Left pad a String with a specified character.

Pad to a size of size.

 StringUtils.leftPad(null, *, *)     = null
 StringUtils.leftPad("", 3, 'z')     = "zzz"
 StringUtils.leftPad("bat", 3, 'z')  = "bat"
 StringUtils.leftPad("bat", 5, 'z')  = "zzbat"
 StringUtils.leftPad("bat", 1, 'z')  = "bat"
 StringUtils.leftPad("bat", -1, 'z') = "bat"
 
static StringleftPad(String str, int size, String padStr)

Left pad a String with a specified String.

Pad to a size of size.

 StringUtils.leftPad(null, *, *)      = null
 StringUtils.leftPad("", 3, "z")      = "zzz"
 StringUtils.leftPad("bat", 3, "yz")  = "bat"
 StringUtils.leftPad("bat", 5, "yz")  = "yzbat"
 StringUtils.leftPad("bat", 8, "yz")  = "yzyzybat"
 StringUtils.leftPad("bat", 1, "yz")  = "bat"
 StringUtils.leftPad("bat", -1, "yz") = "bat"
 StringUtils.leftPad("bat", 5, null)  = "  bat"
 StringUtils.leftPad("bat", 5, "")    = "  bat"
 
static StringlowerCase(String str)

Converts a String to lower case as per {@link String#toLowerCase()}.

A null input String returns null.

 StringUtils.lowerCase(null)  = null
 StringUtils.lowerCase("")    = ""
 StringUtils.lowerCase("aBc") = "abc"
 
static Stringmid(String str, int pos, int len)

Gets len characters from the middle of a String.

If len characters are not available, the remainder of the String will be returned without an exception.

static intordinalIndexOf(String str, String searchStr, int ordinal)

Finds the n-th index within a String, handling null.

static Stringoverlay(String str, String overlay, int start, int end)

Overlays part of a String with another String.

A null string input returns null.

static StringoverlayString(String text, String overlay, int start, int end)

Overlays part of a String with another String.

 StringUtils.overlayString(null, *, *, *)           = NullPointerException
 StringUtils.overlayString(*, null, *, *)           = NullPointerException
 StringUtils.overlayString("", "abc", 0, 0)         = "abc"
 StringUtils.overlayString("abcdef", null, 2, 4)    = "abef"
 StringUtils.overlayString("abcdef", "", 2, 4)      = "abef"
 StringUtils.overlayString("abcdef", "zzzz", 2, 4)  = "abzzzzef"
 StringUtils.overlayString("abcdef", "zzzz", 4, 2)  = "abcdzzzzcdef"
 StringUtils.overlayString("abcdef", "zzzz", -1, 4) = IndexOutOfBoundsException
 StringUtils.overlayString("abcdef", "zzzz", 2, 8)  = IndexOutOfBoundsException
 
static Stringprechomp(String str, String sep)

Remove the first value of a supplied String, and everything before it from a String.

static Stringremove(String str, String remove)

Removes all occurances of a substring from within the source string.

A null source string will return null.

static Stringremove(String str, char remove)

Removes all occurances of a character from within the source string.

A null source string will return null.

static StringremoveEnd(String str, String remove)

Removes a substring only if it is at the end of a source string, otherwise returns the source string.

A null source string will return null.

static StringremoveStart(String str, String remove)

Removes a substring only if it is at the begining of a source string, otherwise returns the source string.

A null source string will return null.

static Stringrepeat(String str, int repeat)

Repeat a String repeat times to form a new String.

 StringUtils.repeat(null, 2) = null
 StringUtils.repeat("", 0)   = ""
 StringUtils.repeat("", 2)   = ""
 StringUtils.repeat("a", 3)  = "aaa"
 StringUtils.repeat("ab", 2) = "abab"
 StringUtils.repeat("a", -2) = ""
 
static Stringreplace(String text, String repl, String with)

Replaces all occurrences of a String within another String.

A null reference passed to this method is a no-op.

 StringUtils.replace(null, *, *)        = null
 StringUtils.replace("", *, *)          = ""
 StringUtils.replace("any", null, *)    = "any"
 StringUtils.replace("any", *, null)    = "any"
 StringUtils.replace("any", "", *)      = "any"
 StringUtils.replace("aba", "a", null)  = "aba"
 StringUtils.replace("aba", "a", "")    = "b"
 StringUtils.replace("aba", "a", "z")   = "zbz"
 
static Stringreplace(String text, String repl, String with, int max)

Replaces a String with another String inside a larger String, for the first max values of the search String.

A null reference passed to this method is a no-op.

 StringUtils.replace(null, *, *, *)         = null
 StringUtils.replace("", *, *, *)           = ""
 StringUtils.replace("any", null, *, *)     = "any"
 StringUtils.replace("any", *, null, *)     = "any"
 StringUtils.replace("any", "", *, *)       = "any"
 StringUtils.replace("any", *, *, 0)        = "any"
 StringUtils.replace("abaa", "a", null, -1) = "abaa"
 StringUtils.replace("abaa", "a", "", -1)   = "b"
 StringUtils.replace("abaa", "a", "z", 0)   = "abaa"
 StringUtils.replace("abaa", "a", "z", 1)   = "zbaa"
 StringUtils.replace("abaa", "a", "z", 2)   = "zbza"
 StringUtils.replace("abaa", "a", "z", -1)  = "zbzz"
 
static StringreplaceChars(String str, char searchChar, char replaceChar)

Replaces all occurrences of a character in a String with another.

static StringreplaceChars(String str, String searchChars, String replaceChars)

Replaces multiple characters in a String in one go.

static StringreplaceOnce(String text, String repl, String with)

Replaces a String with another String inside a larger String, once.

A null reference passed to this method is a no-op.

 StringUtils.replaceOnce(null, *, *)        = null
 StringUtils.replaceOnce("", *, *)          = ""
 StringUtils.replaceOnce("any", null, *)    = "any"
 StringUtils.replaceOnce("any", *, null)    = "any"
 StringUtils.replaceOnce("any", "", *)      = "any"
 StringUtils.replaceOnce("aba", "a", null)  = "aba"
 StringUtils.replaceOnce("aba", "a", "")    = "ba"
 StringUtils.replaceOnce("aba", "a", "z")   = "zba"
 
static Stringreverse(String str)

Reverses a String as per {@link StringBuffer#reverse()}.

A null String returns null.

 StringUtils.reverse(null)  = null
 StringUtils.reverse("")    = ""
 StringUtils.reverse("bat") = "tab"
 
static StringreverseDelimited(String str, char separatorChar)

Reverses a String that is delimited by a specific character.

The Strings between the delimiters are not reversed.

static StringreverseDelimitedString(String str, String separatorChars)

Reverses a String that is delimited by a specific character.

The Strings between the delimiters are not reversed.

static Stringright(String str, int len)

Gets the rightmost len characters of a String.

If len characters are not available, or the String is null, the String will be returned without an an exception.

static StringrightPad(String str, int size)

Right pad a String with spaces (' ').

The String is padded to the size of size.

 StringUtils.rightPad(null, *)   = null
 StringUtils.rightPad("", 3)     = "   "
 StringUtils.rightPad("bat", 3)  = "bat"
 StringUtils.rightPad("bat", 5)  = "bat  "
 StringUtils.rightPad("bat", 1)  = "bat"
 StringUtils.rightPad("bat", -1) = "bat"
 
static StringrightPad(String str, int size, char padChar)

Right pad a String with a specified character.

The String is padded to the size of size.

 StringUtils.rightPad(null, *, *)     = null
 StringUtils.rightPad("", 3, 'z')     = "zzz"
 StringUtils.rightPad("bat", 3, 'z')  = "bat"
 StringUtils.rightPad("bat", 5, 'z')  = "batzz"
 StringUtils.rightPad("bat", 1, 'z')  = "bat"
 StringUtils.rightPad("bat", -1, 'z') = "bat"
 
static StringrightPad(String str, int size, String padStr)

Right pad a String with a specified String.

The String is padded to the size of size.

 StringUtils.rightPad(null, *, *)      = null
 StringUtils.rightPad("", 3, "z")      = "zzz"
 StringUtils.rightPad("bat", 3, "yz")  = "bat"
 StringUtils.rightPad("bat", 5, "yz")  = "batyz"
 StringUtils.rightPad("bat", 8, "yz")  = "batyzyzy"
 StringUtils.rightPad("bat", 1, "yz")  = "bat"
 StringUtils.rightPad("bat", -1, "yz") = "bat"
 StringUtils.rightPad("bat", 5, null)  = "bat  "
 StringUtils.rightPad("bat", 5, "")    = "bat  "
 
static String[]split(String str)

Splits the provided text into an array, using whitespace as the separator.

static String[]split(String str, char separatorChar)

Splits the provided text into an array, separator specified.

static String[]split(String str, String separatorChars)

Splits the provided text into an array, separators specified.

static String[]split(String str, String separatorChars, int max)

Splits the provided text into an array with a maximum length, separators specified.

The separator is not included in the returned String array.

static String[]splitByWholeSeparator(String str, String separator)

Splits the provided text into an array, separator string specified.

The separator(s) will not be included in the returned String array.

static String[]splitByWholeSeparator(String str, String separator, int max)

Splits the provided text into an array, separator string specified.

static String[]splitPreserveAllTokens(String str)

Splits the provided text into an array, using whitespace as the separator, preserving all tokens, including empty tokens created by adjacent separators.

static String[]splitPreserveAllTokens(String str, char separatorChar)

Splits the provided text into an array, separator specified, preserving all tokens, including empty tokens created by adjacent separators.

static String[]splitPreserveAllTokens(String str, String separatorChars)

Splits the provided text into an array, separators specified, preserving all tokens, including empty tokens created by adjacent separators.

static String[]splitPreserveAllTokens(String str, String separatorChars, int max)

Splits the provided text into an array with a maximum length, separators specified, preserving all tokens, including empty tokens created by adjacent separators.

The separator is not included in the returned String array.

static Stringstrip(String str)

Strips whitespace from the start and end of a String.

This is similar to {@link #trim(String)} but removes whitespace.

static Stringstrip(String str, String stripChars)

Strips any of a set of characters from the start and end of a String.

static String[]stripAll(String[] strs)

Strips whitespace from the start and end of every String in an array.

static String[]stripAll(String[] strs, String stripChars)

Strips any of a set of characters from the start and end of every String in an array.

Whitespace is defined by {@link Character#isWhitespace(char)}.

A new array is returned each time, except for length zero.

static StringstripEnd(String str, String stripChars)

Strips any of a set of characters from the end of a String.

A null input String returns null.

static StringstripStart(String str, String stripChars)

Strips any of a set of characters from the start of a String.

A null input String returns null.

static StringstripToEmpty(String str)

Strips whitespace from the start and end of a String returning an empty String if null input.

This is similar to {@link #trimToEmpty(String)} but removes whitespace.

static StringstripToNull(String str)

Strips whitespace from the start and end of a String returning null if the String is empty ("") after the strip.

This is similar to {@link #trimToNull(String)} but removes whitespace.

static Stringsubstring(String str, int start)

Gets a substring from the specified String avoiding exceptions.

A negative start position can be used to start n characters from the end of the String.

A null String will return null.

static Stringsubstring(String str, int start, int end)

Gets a substring from the specified String avoiding exceptions.

A negative start position can be used to start/end n characters from the end of the String.

The returned substring starts with the character in the start position and ends before the end position.

static StringsubstringAfter(String str, String separator)

Gets the substring after the first occurrence of a separator.

static StringsubstringAfterLast(String str, String separator)

Gets the substring after the last occurrence of a separator.

static StringsubstringBefore(String str, String separator)

Gets the substring before the first occurrence of a separator.

static StringsubstringBeforeLast(String str, String separator)

Gets the substring before the last occurrence of a separator.

static StringsubstringBetween(String str, String tag)

Gets the String that is nested in between two instances of the same String.

A null input String returns null.

static StringsubstringBetween(String str, String open, String close)

Gets the String that is nested in between two Strings.

static StringswapCase(String str)

Swaps the case of a String changing upper and title case to lower case, and lower case to upper case.

  • Upper case character converts to Lower case
  • Title case character converts to Lower case
  • Lower case character converts to Upper case

For a word based algorithm, see {@link WordUtils#swapCase(String)}.

static Stringtrim(String str)

Removes control characters (char <= 32) from both ends of this String, handling null by returning null.

The String is trimmed using {@link String#trim()}.

static StringtrimToEmpty(String str)

Removes control characters (char <= 32) from both ends of this String returning an empty String ("") if the String is empty ("") after the trim or if it is null.

static StringtrimToNull(String str)

Removes control characters (char <= 32) from both ends of this String returning null if the String is empty ("") after the trim or if it is null.

static Stringuncapitalise(String str)

Uncapitalizes a String changing the first letter to title case as per {@link Character#toLowerCase(char)}.

static Stringuncapitalize(String str)

Uncapitalizes a String changing the first letter to title case as per {@link Character#toLowerCase(char)}.

static StringupperCase(String str)

Converts a String to upper case as per {@link String#toUpperCase()}.

A null input String returns null.

 StringUtils.upperCase(null)  = null
 StringUtils.upperCase("")    = ""
 StringUtils.upperCase("aBc") = "ABC"
 

Field Detail

EMPTY

public static final String EMPTY
The empty String "".

Since: 2.0

INDEX_NOT_FOUND

public static final int INDEX_NOT_FOUND
Represents a failed index search.

Since: 2.1

Constructor Detail

StringUtils

public StringUtils()

StringUtils instances should NOT be constructed in standard programming. Instead, the class should be used as StringUtils.trim(" foo ");.

This constructor is public to permit tools that require a JavaBean instance to operate.

Method Detail

abbreviate

public static String abbreviate(String str, int maxWidth)

Abbreviates a String using ellipses. This will turn "Now is the time for all good men" into "Now is the time for..."

Specifically:

 StringUtils.abbreviate(null, *)      = null
 StringUtils.abbreviate("", 4)        = ""
 StringUtils.abbreviate("abcdefg", 6) = "abc..."
 StringUtils.abbreviate("abcdefg", 7) = "abcdefg"
 StringUtils.abbreviate("abcdefg", 8) = "abcdefg"
 StringUtils.abbreviate("abcdefg", 4) = "a..."
 StringUtils.abbreviate("abcdefg", 3) = IllegalArgumentException
 

Parameters: str the String to check, may be null maxWidth maximum length of result String, must be at least 4

Returns: abbreviated String, null if null String input

Throws: IllegalArgumentException if the width is too small

Since: 2.0

abbreviate

public static String abbreviate(String str, int offset, int maxWidth)

Abbreviates a String using ellipses. This will turn "Now is the time for all good men" into "...is the time for..."

Works like abbreviate(String, int), but allows you to specify a "left edge" offset. Note that this left edge is not necessarily going to be the leftmost character in the result, or the first character following the ellipses, but it will appear somewhere in the result.

In no case will it return a String of length greater than maxWidth.

 StringUtils.abbreviate(null, *, *)                = null
 StringUtils.abbreviate("", 0, 4)                  = ""
 StringUtils.abbreviate("abcdefghijklmno", -1, 10) = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 0, 10)  = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 1, 10)  = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 4, 10)  = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 5, 10)  = "...fghi..."
 StringUtils.abbreviate("abcdefghijklmno", 6, 10)  = "...ghij..."
 StringUtils.abbreviate("abcdefghijklmno", 8, 10)  = "...ijklmno"
 StringUtils.abbreviate("abcdefghijklmno", 10, 10) = "...ijklmno"
 StringUtils.abbreviate("abcdefghijklmno", 12, 10) = "...ijklmno"
 StringUtils.abbreviate("abcdefghij", 0, 3)        = IllegalArgumentException
 StringUtils.abbreviate("abcdefghij", 5, 6)        = IllegalArgumentException
 

Parameters: str the String to check, may be null offset left edge of source String maxWidth maximum length of result String, must be at least 4

Returns: abbreviated String, null if null String input

Throws: IllegalArgumentException if the width is too small

Since: 2.0

capitalise

public static String capitalise(String str)

Deprecated: Use the standardly named {@link #capitalize(String)}. Method will be removed in Commons Lang 3.0.

Capitalizes a String changing the first letter to title case as per {@link Character#toTitleCase(char)}. No other letters are changed.

Parameters: str the String to capitalize, may be null

Returns: the capitalized String, null if null String input

capitaliseAllWords

public static String capitaliseAllWords(String str)

Deprecated: Use the relocated {@link WordUtils#capitalize(String)}. Method will be removed in Commons Lang 3.0.

Capitalizes all the whitespace separated words in a String. Only the first letter of each word is changed.

Whitespace is defined by {@link Character#isWhitespace(char)}. A null input String returns null.

Parameters: str the String to capitalize, may be null

Returns: capitalized String, null if null String input

capitalize

public static String capitalize(String str)

Capitalizes a String changing the first letter to title case as per {@link Character#toTitleCase(char)}. No other letters are changed.

For a word based algorithm, see {@link WordUtils#capitalize(String)}. A null input String returns null.

 StringUtils.capitalize(null)  = null
 StringUtils.capitalize("")    = ""
 StringUtils.capitalize("cat") = "Cat"
 StringUtils.capitalize("cAt") = "CAt"
 

Parameters: str the String to capitalize, may be null

Returns: the capitalized String, null if null String input

Since: 2.0

See Also: capitalize uncapitalize

center

public static String center(String str, int size)

Centers a String in a larger String of size size using the space character (' ').

If the size is less than the String length, the String is returned. A null String returns null. A negative size is treated as zero.

Equivalent to center(str, size, " ").

 StringUtils.center(null, *)   = null
 StringUtils.center("", 4)     = "    "
 StringUtils.center("ab", -1)  = "ab"
 StringUtils.center("ab", 4)   = " ab "
 StringUtils.center("abcd", 2) = "abcd"
 StringUtils.center("a", 4)    = " a  "
 

Parameters: str the String to center, may be null size the int size of new String, negative treated as zero

Returns: centered String, null if null String input

center

public static String center(String str, int size, char padChar)

Centers a String in a larger String of size size. Uses a supplied character as the value to pad the String with.

If the size is less than the String length, the String is returned. A null String returns null. A negative size is treated as zero.

 StringUtils.center(null, *, *)     = null
 StringUtils.center("", 4, ' ')     = "    "
 StringUtils.center("ab", -1, ' ')  = "ab"
 StringUtils.center("ab", 4, ' ')   = " ab"
 StringUtils.center("abcd", 2, ' ') = "abcd"
 StringUtils.center("a", 4, ' ')    = " a  "
 StringUtils.center("a", 4, 'y')    = "yayy"
 

Parameters: str the String to center, may be null size the int size of new String, negative treated as zero padChar the character to pad the new String with

Returns: centered String, null if null String input

Since: 2.0

center

public static String center(String str, int size, String padStr)

Centers a String in a larger String of size size. Uses a supplied String as the value to pad the String with.

If the size is less than the String length, the String is returned. A null String returns null. A negative size is treated as zero.

 StringUtils.center(null, *, *)     = null
 StringUtils.center("", 4, " ")     = "    "
 StringUtils.center("ab", -1, " ")  = "ab"
 StringUtils.center("ab", 4, " ")   = " ab"
 StringUtils.center("abcd", 2, " ") = "abcd"
 StringUtils.center("a", 4, " ")    = " a  "
 StringUtils.center("a", 4, "yz")   = "yayz"
 StringUtils.center("abc", 7, null) = "  abc  "
 StringUtils.center("abc", 7, "")   = "  abc  "
 

Parameters: str the String to center, may be null size the int size of new String, negative treated as zero padStr the String to pad the new String with, must not be null or empty

Returns: centered String, null if null String input

Throws: IllegalArgumentException if padStr is null or empty

chomp

public static String chomp(String str)

Removes one newline from end of a String if it's there, otherwise leave it alone. A newline is "\n", "\r", or "\r\n".

NOTE: This method changed in 2.0. It now more closely matches Perl chomp.

 StringUtils.chomp(null)          = null
 StringUtils.chomp("")            = ""
 StringUtils.chomp("abc \r")      = "abc "
 StringUtils.chomp("abc\n")       = "abc"
 StringUtils.chomp("abc\r\n")     = "abc"
 StringUtils.chomp("abc\r\n\r\n") = "abc\r\n"
 StringUtils.chomp("abc\n\r")     = "abc\n"
 StringUtils.chomp("abc\n\rabc")  = "abc\n\rabc"
 StringUtils.chomp("\r")          = ""
 StringUtils.chomp("\n")          = ""
 StringUtils.chomp("\r\n")        = ""
 

Parameters: str the String to chomp a newline from, may be null

Returns: String without newline, null if null String input

chomp

public static String chomp(String str, String separator)

Removes separator from the end of str if it's there, otherwise leave it alone.

NOTE: This method changed in version 2.0. It now more closely matches Perl chomp. For the previous behavior, use {@link #substringBeforeLast(String, String)}. This method uses {@link String#endsWith(String)}.

 StringUtils.chomp(null, *)         = null
 StringUtils.chomp("", *)           = ""
 StringUtils.chomp("foobar", "bar") = "foo"
 StringUtils.chomp("foobar", "baz") = "foobar"
 StringUtils.chomp("foo", "foo")    = ""
 StringUtils.chomp("foo ", "foo")   = "foo "
 StringUtils.chomp(" foo", "foo")   = " "
 StringUtils.chomp("foo", "foooo")  = "foo"
 StringUtils.chomp("foo", "")       = "foo"
 StringUtils.chomp("foo", null)     = "foo"
 

Parameters: str the String to chomp from, may be null separator separator String, may be null

Returns: String without trailing separator, null if null String input

chompLast

public static String chompLast(String str)

Deprecated: Use {@link #chomp(String)} instead. Method will be removed in Commons Lang 3.0.

Remove any "\n" if and only if it is at the end of the supplied String.

Parameters: str the String to chomp from, must not be null

Returns: String without chomped ending

Throws: NullPointerException if str is null

chompLast

public static String chompLast(String str, String sep)

Deprecated: Use {@link #chomp(String,String)} instead. Method will be removed in Commons Lang 3.0.

Remove a value if and only if the String ends with that value.

Parameters: str the String to chomp from, must not be null sep the String to chomp, must not be null

Returns: String without chomped ending

Throws: NullPointerException if str or sep is null

chop

public static String chop(String str)

Remove the last character from a String.

If the String ends in \r\n, then remove both of them.

 StringUtils.chop(null)          = null
 StringUtils.chop("")            = ""
 StringUtils.chop("abc \r")      = "abc "
 StringUtils.chop("abc\n")       = "abc"
 StringUtils.chop("abc\r\n")     = "abc"
 StringUtils.chop("abc")         = "ab"
 StringUtils.chop("abc\nabc")    = "abc\nab"
 StringUtils.chop("a")           = ""
 StringUtils.chop("\r")          = ""
 StringUtils.chop("\n")          = ""
 StringUtils.chop("\r\n")        = ""
 

Parameters: str the String to chop last character from, may be null

Returns: String without last character, null if null String input

chopNewline

public static String chopNewline(String str)

Deprecated: Use {@link #chomp(String)} instead. Method will be removed in Commons Lang 3.0.

Removes \n from end of a String if it's there. If a \r precedes it, then remove that too.

Parameters: str the String to chop a newline from, must not be null

Returns: String without newline

Throws: NullPointerException if str is null

clean

public static String clean(String str)

Deprecated: Use the clearer named {@link #trimToEmpty(String)}. Method will be removed in Commons Lang 3.0.

Removes control characters (char <= 32) from both ends of this String, handling null by returning an empty String ("").

 StringUtils.clean(null)          = ""
 StringUtils.clean("")            = ""
 StringUtils.clean("abc")         = "abc"
 StringUtils.clean("    abc    ") = "abc"
 StringUtils.clean("     ")       = ""
 

Parameters: str the String to clean, may be null

Returns: the trimmed text, never null

See Also: java.lang.String#trim()

concatenate

public static String concatenate(Object[] array)

Deprecated: Use the better named {@link #join(Object[])} instead. Method will be removed in Commons Lang 3.0.

Concatenates elements of an array into a single String. Null objects or empty strings within the array are represented by empty strings.

 StringUtils.concatenate(null)            = null
 StringUtils.concatenate([])              = ""
 StringUtils.concatenate([null])          = ""
 StringUtils.concatenate(["a", "b", "c"]) = "abc"
 StringUtils.concatenate([null, "", "a"]) = "a"
 

Parameters: array the array of values to concatenate, may be null

Returns: the concatenated String, null if null array input

contains

public static boolean contains(String str, char searchChar)

Checks if String contains a search character, handling null. This method uses {@link String#indexOf(int)}.

A null or empty ("") String will return false.

 StringUtils.contains(null, *)    = false
 StringUtils.contains("", *)      = false
 StringUtils.contains("abc", 'a') = true
 StringUtils.contains("abc", 'z') = false
 

Parameters: str the String to check, may be null searchChar the character to find

Returns: true if the String contains the search character, false if not or null string input

Since: 2.0

contains

public static boolean contains(String str, String searchStr)

Checks if String contains a search String, handling null. This method uses {@link String#indexOf(int)}.

A null String will return false.

 StringUtils.contains(null, *)     = false
 StringUtils.contains(*, null)     = false
 StringUtils.contains("", "")      = true
 StringUtils.contains("abc", "")   = true
 StringUtils.contains("abc", "a")  = true
 StringUtils.contains("abc", "z")  = false
 

Parameters: str the String to check, may be null searchStr the String to find, may be null

Returns: true if the String contains the search String, false if not or null string input

Since: 2.0

containsNone

public static boolean containsNone(String str, char[] invalidChars)

Checks that the String does not contain certain characters.

A null String will return true. A null invalid character array will return true. An empty String ("") always returns true.

 StringUtils.containsNone(null, *)       = true
 StringUtils.containsNone(*, null)       = true
 StringUtils.containsNone("", *)         = true
 StringUtils.containsNone("ab", '')      = true
 StringUtils.containsNone("abab", 'xyz') = true
 StringUtils.containsNone("ab1", 'xyz')  = true
 StringUtils.containsNone("abz", 'xyz')  = false
 

Parameters: str the String to check, may be null invalidChars an array of invalid chars, may be null

Returns: true if it contains none of the invalid chars, or is null

Since: 2.0

containsNone

public static boolean containsNone(String str, String invalidChars)

Checks that the String does not contain certain characters.

A null String will return true. A null invalid character array will return true. An empty String ("") always returns true.

 StringUtils.containsNone(null, *)       = true
 StringUtils.containsNone(*, null)       = true
 StringUtils.containsNone("", *)         = true
 StringUtils.containsNone("ab", "")      = true
 StringUtils.containsNone("abab", "xyz") = true
 StringUtils.containsNone("ab1", "xyz")  = true
 StringUtils.containsNone("abz", "xyz")  = false
 

Parameters: str the String to check, may be null invalidChars a String of invalid chars, may be null

Returns: true if it contains none of the invalid chars, or is null

Since: 2.0

containsOnly

public static boolean containsOnly(String str, char[] valid)

Checks if the String contains only certain characters.

A null String will return false. A null valid character array will return false. An empty String ("") always returns true.

 StringUtils.containsOnly(null, *)       = false
 StringUtils.containsOnly(*, null)       = false
 StringUtils.containsOnly("", *)         = true
 StringUtils.containsOnly("ab", '')      = false
 StringUtils.containsOnly("abab", 'abc') = true
 StringUtils.containsOnly("ab1", 'abc')  = false
 StringUtils.containsOnly("abz", 'abc')  = false
 

Parameters: str the String to check, may be null valid an array of valid chars, may be null

Returns: true if it only contains valid chars and is non-null

containsOnly

public static boolean containsOnly(String str, String validChars)

Checks if the String contains only certain characters.

A null String will return false. A null valid character String will return false. An empty String ("") always returns true.

 StringUtils.containsOnly(null, *)       = false
 StringUtils.containsOnly(*, null)       = false
 StringUtils.containsOnly("", *)         = true
 StringUtils.containsOnly("ab", "")      = false
 StringUtils.containsOnly("abab", "abc") = true
 StringUtils.containsOnly("ab1", "abc")  = false
 StringUtils.containsOnly("abz", "abc")  = false
 

Parameters: str the String to check, may be null validChars a String of valid chars, may be null

Returns: true if it only contains valid chars and is non-null

Since: 2.0

countMatches

public static int countMatches(String str, String sub)

Counts how many times the substring appears in the larger String.

A null or empty ("") String input returns 0.

 StringUtils.countMatches(null, *)       = 0
 StringUtils.countMatches("", *)         = 0
 StringUtils.countMatches("abba", null)  = 0
 StringUtils.countMatches("abba", "")    = 0
 StringUtils.countMatches("abba", "a")   = 2
 StringUtils.countMatches("abba", "ab")  = 1
 StringUtils.countMatches("abba", "xxx") = 0
 

Parameters: str the String to check, may be null sub the substring to count, may be null

Returns: the number of occurrences, 0 if either String is null

defaultIfEmpty

public static String defaultIfEmpty(String str, String defaultStr)

Returns either the passed in String, or if the String is empty or null, the value of defaultStr.

 StringUtils.defaultIfEmpty(null, "NULL")  = "NULL"
 StringUtils.defaultIfEmpty("", "NULL")    = "NULL"
 StringUtils.defaultIfEmpty("bat", "NULL") = "bat"
 

Parameters: str the String to check, may be null defaultStr the default String to return if the input is empty ("") or null, may be null

Returns: the passed in String, or the default

See Also: StringUtils

defaultString

public static String defaultString(String str)

Returns either the passed in String, or if the String is null, an empty String ("").

 StringUtils.defaultString(null)  = ""
 StringUtils.defaultString("")    = ""
 StringUtils.defaultString("bat") = "bat"
 

Parameters: str the String to check, may be null

Returns: the passed in String, or the empty String if it was null

See Also: toString String#valueOf(Object)

defaultString

public static String defaultString(String str, String defaultStr)

Returns either the passed in String, or if the String is null, the value of defaultStr.

 StringUtils.defaultString(null, "NULL")  = "NULL"
 StringUtils.defaultString("", "NULL")    = ""
 StringUtils.defaultString("bat", "NULL") = "bat"
 

Parameters: str the String to check, may be null defaultStr the default String to return if the input is null, may be null

Returns: the passed in String, or the default if it was null

See Also: toString String#valueOf(Object)

deleteSpaces

public static String deleteSpaces(String str)

Deprecated: Use the better localized {@link #deleteWhitespace(String)}. Method will be removed in Commons Lang 3.0.

Deletes all 'space' characters from a String as defined by {@link Character#isSpace(char)}.

This is the only StringUtils method that uses the isSpace definition. You are advised to use {@link #deleteWhitespace(String)} instead as whitespace is much better localized.

 StringUtils.deleteSpaces(null)           = null
 StringUtils.deleteSpaces("")             = ""
 StringUtils.deleteSpaces("abc")          = "abc"
 StringUtils.deleteSpaces(" \t  abc \n ") = "abc"
 StringUtils.deleteSpaces("ab  c")        = "abc"
 StringUtils.deleteSpaces("a\nb\tc     ") = "abc"
 

Spaces are defined as {' ', '\t', '\r', '\n', '\b'} in line with the deprecated isSpace method.

Parameters: str the String to delete spaces from, may be null

Returns: the String without 'spaces', null if null String input

deleteWhitespace

public static String deleteWhitespace(String str)

Deletes all whitespaces from a String as defined by {@link Character#isWhitespace(char)}.

 StringUtils.deleteWhitespace(null)         = null
 StringUtils.deleteWhitespace("")           = ""
 StringUtils.deleteWhitespace("abc")        = "abc"
 StringUtils.deleteWhitespace("   ab  c  ") = "abc"
 

Parameters: str the String to delete whitespace from, may be null

Returns: the String without whitespaces, null if null String input

difference

public static String difference(String str1, String str2)

Compares two Strings, and returns the portion where they differ. (More precisely, return the remainder of the second String, starting from where it's different from the first.)

For example, difference("i am a machine", "i am a robot") -> "robot".

 StringUtils.difference(null, null) = null
 StringUtils.difference("", "") = ""
 StringUtils.difference("", "abc") = "abc"
 StringUtils.difference("abc", "") = ""
 StringUtils.difference("abc", "abc") = ""
 StringUtils.difference("ab", "abxyz") = "xyz"
 StringUtils.difference("abcde", "abxyz") = "xyz"
 StringUtils.difference("abcde", "xyz") = "xyz"
 

Parameters: str1 the first String, may be null str2 the second String, may be null

Returns: the portion of str2 where it differs from str1; returns the empty String if they are equal

Since: 2.0

equals

public static boolean equals(String str1, String str2)

Compares two Strings, returning true if they are equal.

nulls are handled without exceptions. Two null references are considered to be equal. The comparison is case sensitive.

 StringUtils.equals(null, null)   = true
 StringUtils.equals(null, "abc")  = false
 StringUtils.equals("abc", null)  = false
 StringUtils.equals("abc", "abc") = true
 StringUtils.equals("abc", "ABC") = false
 

Parameters: str1 the first String, may be null str2 the second String, may be null

Returns: true if the Strings are equal, case sensitive, or both null

See Also: java.lang.String#equals(Object)

equalsIgnoreCase

public static boolean equalsIgnoreCase(String str1, String str2)

Compares two Strings, returning true if they are equal ignoring the case.

nulls are handled without exceptions. Two null references are considered equal. Comparison is case insensitive.

 StringUtils.equalsIgnoreCase(null, null)   = true
 StringUtils.equalsIgnoreCase(null, "abc")  = false
 StringUtils.equalsIgnoreCase("abc", null)  = false
 StringUtils.equalsIgnoreCase("abc", "abc") = true
 StringUtils.equalsIgnoreCase("abc", "ABC") = true
 

Parameters: str1 the first String, may be null str2 the second String, may be null

Returns: true if the Strings are equal, case insensitive, or both null

See Also: java.lang.String#equalsIgnoreCase(String)

escape

public static String escape(String str)

Deprecated: Use {@link StringEscapeUtils#escapeJava(String)} This method will be removed in Commons Lang 3.0

Escapes any values it finds into their String form.

So a tab becomes the characters '\\' and 't'.

As of Lang 2.0, this calls {@link StringEscapeUtils#escapeJava(String)} behind the scenes.

Parameters: str String to escape values in

Returns: String with escaped values

Throws: NullPointerException if str is null

See Also: StringEscapeUtils

getChomp

public static String getChomp(String str, String sep)

Deprecated: Use {@link #substringAfterLast(String, String)} instead (although this doesn't include the separator) Method will be removed in Commons Lang 3.0.

Remove everything and return the last value of a supplied String, and everything after it from a String.

Parameters: str the String to chomp from, must not be null sep the String to chomp, must not be null

Returns: String chomped

Throws: NullPointerException if str or sep is null

getLevenshteinDistance

public static int getLevenshteinDistance(String s, String t)

Find the Levenshtein distance between two Strings.

This is the number of changes needed to change one String into another, where each change is a single character modification (deletion, insertion or substitution).

This implementation of the Levenshtein distance algorithm is from http://www.merriampark.com/ld.htm

 StringUtils.getLevenshteinDistance(null, *)             = IllegalArgumentException
 StringUtils.getLevenshteinDistance(*, null)             = IllegalArgumentException
 StringUtils.getLevenshteinDistance("","")               = 0
 StringUtils.getLevenshteinDistance("","a")              = 1
 StringUtils.getLevenshteinDistance("aaapppp", "")       = 7
 StringUtils.getLevenshteinDistance("frog", "fog")       = 1
 StringUtils.getLevenshteinDistance("fly", "ant")        = 3
 StringUtils.getLevenshteinDistance("elephant", "hippo") = 7
 StringUtils.getLevenshteinDistance("hippo", "elephant") = 7
 StringUtils.getLevenshteinDistance("hippo", "zzzzzzzz") = 8
 StringUtils.getLevenshteinDistance("hello", "hallo")    = 1
 

Parameters: s the first String, must not be null t the second String, must not be null

Returns: result distance

Throws: IllegalArgumentException if either String input null

getNestedString

public static String getNestedString(String str, String tag)

Deprecated: Use the better named {@link #substringBetween(String, String)}. Method will be removed in Commons Lang 3.0.

Gets the String that is nested in between two instances of the same String.

A null input String returns null. A null tag returns null.

 StringUtils.getNestedString(null, *)            = null
 StringUtils.getNestedString("", "")             = ""
 StringUtils.getNestedString("", "tag")          = null
 StringUtils.getNestedString("tagabctag", null)  = null
 StringUtils.getNestedString("tagabctag", "")    = ""
 StringUtils.getNestedString("tagabctag", "tag") = "abc"
 

Parameters: str the String containing nested-string, may be null tag the String before and after nested-string, may be null

Returns: the nested String, null if no match

getNestedString

public static String getNestedString(String str, String open, String close)

Deprecated: Use the better named {@link #substringBetween(String, String, String)}. Method will be removed in Commons Lang 3.0.

Gets the String that is nested in between two Strings. Only the first match is returned.

A null input String returns null. A null open/close returns null (no match). An empty ("") open/close returns an empty string.

 StringUtils.getNestedString(null, *, *)          = null
 StringUtils.getNestedString("", "", "")          = ""
 StringUtils.getNestedString("", "", "tag")       = null
 StringUtils.getNestedString("", "tag", "tag")    = null
 StringUtils.getNestedString("yabcz", null, null) = null
 StringUtils.getNestedString("yabcz", "", "")     = ""
 StringUtils.getNestedString("yabcz", "y", "z")   = "abc"
 StringUtils.getNestedString("yabczyabcz", "y", "z")   = "abc"
 

Parameters: str the String containing nested-string, may be null open the String before nested-string, may be null close the String after nested-string, may be null

Returns: the nested String, null if no match

getPrechomp

public static String getPrechomp(String str, String sep)

Deprecated: Use {@link #substringBefore(String,String)} instead (although this doesn't include the separator). Method will be removed in Commons Lang 3.0.

Remove and return everything before the first value of a supplied String from another String.

Parameters: str the String to chomp from, must not be null sep the String to chomp, must not be null

Returns: String prechomped

Throws: NullPointerException if str or sep is null

indexOf

public static int indexOf(String str, char searchChar)

Finds the first index within a String, handling null. This method uses {@link String#indexOf(int)}.

A null or empty ("") String will return -1.

 StringUtils.indexOf(null, *)         = -1
 StringUtils.indexOf("", *)           = -1
 StringUtils.indexOf("aabaabaa", 'a') = 0
 StringUtils.indexOf("aabaabaa", 'b') = 2
 

Parameters: str the String to check, may be null searchChar the character to find

Returns: the first index of the search character, -1 if no match or null string input

Since: 2.0

indexOf

public static int indexOf(String str, char searchChar, int startPos)

Finds the first index within a String from a start position, handling null. This method uses {@link String#indexOf(int, int)}.

A null or empty ("") String will return -1. A negative start position is treated as zero. A start position greater than the string length returns -1.

 StringUtils.indexOf(null, *, *)          = -1
 StringUtils.indexOf("", *, *)            = -1
 StringUtils.indexOf("aabaabaa", 'b', 0)  = 2
 StringUtils.indexOf("aabaabaa", 'b', 3)  = 5
 StringUtils.indexOf("aabaabaa", 'b', 9)  = -1
 StringUtils.indexOf("aabaabaa", 'b', -1) = 2
 

Parameters: str the String to check, may be null searchChar the character to find startPos the start position, negative treated as zero

Returns: the first index of the search character, -1 if no match or null string input

Since: 2.0

indexOf

public static int indexOf(String str, String searchStr)

Finds the first index within a String, handling null. This method uses {@link String#indexOf(String)}.

A null String will return -1.

 StringUtils.indexOf(null, *)          = -1
 StringUtils.indexOf(*, null)          = -1
 StringUtils.indexOf("", "")           = 0
 StringUtils.indexOf("aabaabaa", "a")  = 0
 StringUtils.indexOf("aabaabaa", "b")  = 2
 StringUtils.indexOf("aabaabaa", "ab") = 1
 StringUtils.indexOf("aabaabaa", "")   = 0
 

Parameters: str the String to check, may be null searchStr the String to find, may be null

Returns: the first index of the search String, -1 if no match or null string input

Since: 2.0

indexOf

public static int indexOf(String str, String searchStr, int startPos)

Finds the first index within a String, handling null. This method uses {@link String#indexOf(String, int)}.

A null String will return -1. A negative start position is treated as zero. An empty ("") search String always matches. A start position greater than the string length only matches an empty search String.

 StringUtils.indexOf(null, *, *)          = -1
 StringUtils.indexOf(*, null, *)          = -1
 StringUtils.indexOf("", "", 0)           = 0
 StringUtils.indexOf("aabaabaa", "a", 0)  = 0
 StringUtils.indexOf("aabaabaa", "b", 0)  = 2
 StringUtils.indexOf("aabaabaa", "ab", 0) = 1
 StringUtils.indexOf("aabaabaa", "b", 3)  = 5
 StringUtils.indexOf("aabaabaa", "b", 9)  = -1
 StringUtils.indexOf("aabaabaa", "b", -1) = 2
 StringUtils.indexOf("aabaabaa", "", 2)   = 2
 StringUtils.indexOf("abc", "", 9)        = 3
 

Parameters: str the String to check, may be null searchStr the String to find, may be null startPos the start position, negative treated as zero

Returns: the first index of the search String, -1 if no match or null string input

Since: 2.0

indexOfAny

public static int indexOfAny(String str, char[] searchChars)

Search a String to find the first index of any character in the given set of characters.

A null String will return -1. A null or zero length search array will return -1.

 StringUtils.indexOfAny(null, *)                = -1
 StringUtils.indexOfAny("", *)                  = -1
 StringUtils.indexOfAny(*, null)                = -1
 StringUtils.indexOfAny(*, [])                  = -1
 StringUtils.indexOfAny("zzabyycdxx",['z','a']) = 0
 StringUtils.indexOfAny("zzabyycdxx",['b','y']) = 3
 StringUtils.indexOfAny("aba", ['z'])           = -1
 

Parameters: str the String to check, may be null searchChars the chars to search for, may be null

Returns: the index of any of the chars, -1 if no match or null input

Since: 2.0

indexOfAny

public static int indexOfAny(String str, String searchChars)

Search a String to find the first index of any character in the given set of characters.

A null String will return -1. A null search string will return -1.

 StringUtils.indexOfAny(null, *)            = -1
 StringUtils.indexOfAny("", *)              = -1
 StringUtils.indexOfAny(*, null)            = -1
 StringUtils.indexOfAny(*, "")              = -1
 StringUtils.indexOfAny("zzabyycdxx", "za") = 0
 StringUtils.indexOfAny("zzabyycdxx", "by") = 3
 StringUtils.indexOfAny("aba","z")          = -1
 

Parameters: str the String to check, may be null searchChars the chars to search for, may be null

Returns: the index of any of the chars, -1 if no match or null input

Since: 2.0

indexOfAny

public static int indexOfAny(String str, String[] searchStrs)

Find the first index of any of a set of potential substrings.

A null String will return -1. A null or zero length search array will return -1. A null search array entry will be ignored, but a search array containing "" will return 0 if str is not null. This method uses {@link String#indexOf(String)}.

 StringUtils.indexOfAny(null, *)                     = -1
 StringUtils.indexOfAny(*, null)                     = -1
 StringUtils.indexOfAny(*, [])                       = -1
 StringUtils.indexOfAny("zzabyycdxx", ["ab","cd"])   = 2
 StringUtils.indexOfAny("zzabyycdxx", ["cd","ab"])   = 2
 StringUtils.indexOfAny("zzabyycdxx", ["mn","op"])   = -1
 StringUtils.indexOfAny("zzabyycdxx", ["zab","aby"]) = 1
 StringUtils.indexOfAny("zzabyycdxx", [""])          = 0
 StringUtils.indexOfAny("", [""])                    = 0
 StringUtils.indexOfAny("", ["a"])                   = -1
 

Parameters: str the String to check, may be null searchStrs the Strings to search for, may be null

Returns: the first index of any of the searchStrs in str, -1 if no match

indexOfAnyBut

public static int indexOfAnyBut(String str, char[] searchChars)

Search a String to find the first index of any character not in the given set of characters.

A null String will return -1. A null or zero length search array will return -1.

 StringUtils.indexOfAnyBut(null, *)           = -1
 StringUtils.indexOfAnyBut("", *)             = -1
 StringUtils.indexOfAnyBut(*, null)           = -1
 StringUtils.indexOfAnyBut(*, [])             = -1
 StringUtils.indexOfAnyBut("zzabyycdxx",'za') = 3
 StringUtils.indexOfAnyBut("zzabyycdxx", '')  = 0
 StringUtils.indexOfAnyBut("aba", 'ab')       = -1
 

Parameters: str the String to check, may be null searchChars the chars to search for, may be null

Returns: the index of any of the chars, -1 if no match or null input

Since: 2.0

indexOfAnyBut

public static int indexOfAnyBut(String str, String searchChars)

Search a String to find the first index of any character not in the given set of characters.

A null String will return -1. A null search string will return -1.

 StringUtils.indexOfAnyBut(null, *)            = -1
 StringUtils.indexOfAnyBut("", *)              = -1
 StringUtils.indexOfAnyBut(*, null)            = -1
 StringUtils.indexOfAnyBut(*, "")              = -1
 StringUtils.indexOfAnyBut("zzabyycdxx", "za") = 3
 StringUtils.indexOfAnyBut("zzabyycdxx", "")   = 0
 StringUtils.indexOfAnyBut("aba","ab")         = -1
 

Parameters: str the String to check, may be null searchChars the chars to search for, may be null

Returns: the index of any of the chars, -1 if no match or null input

Since: 2.0

indexOfDifference

public static int indexOfDifference(String str1, String str2)

Compares two Strings, and returns the index at which the Strings begin to differ.

For example, indexOfDifference("i am a machine", "i am a robot") -> 7

 StringUtils.indexOfDifference(null, null) = -1
 StringUtils.indexOfDifference("", "") = -1
 StringUtils.indexOfDifference("", "abc") = 0
 StringUtils.indexOfDifference("abc", "") = 0
 StringUtils.indexOfDifference("abc", "abc") = -1
 StringUtils.indexOfDifference("ab", "abxyz") = 2
 StringUtils.indexOfDifference("abcde", "abxyz") = 2
 StringUtils.indexOfDifference("abcde", "xyz") = 0
 

Parameters: str1 the first String, may be null str2 the second String, may be null

Returns: the index where str2 and str1 begin to differ; -1 if they are equal

Since: 2.0

isAlpha

public static boolean isAlpha(String str)

Checks if the String contains only unicode letters.

null will return false. An empty String ("") will return true.

 StringUtils.isAlpha(null)   = false
 StringUtils.isAlpha("")     = true
 StringUtils.isAlpha("  ")   = false
 StringUtils.isAlpha("abc")  = true
 StringUtils.isAlpha("ab2c") = false
 StringUtils.isAlpha("ab-c") = false
 

Parameters: str the String to check, may be null

Returns: true if only contains letters, and is non-null

isAlphanumeric

public static boolean isAlphanumeric(String str)

Checks if the String contains only unicode letters or digits.

null will return false. An empty String ("") will return true.

 StringUtils.isAlphanumeric(null)   = false
 StringUtils.isAlphanumeric("")     = true
 StringUtils.isAlphanumeric("  ")   = false
 StringUtils.isAlphanumeric("abc")  = true
 StringUtils.isAlphanumeric("ab c") = false
 StringUtils.isAlphanumeric("ab2c") = true
 StringUtils.isAlphanumeric("ab-c") = false
 

Parameters: str the String to check, may be null

Returns: true if only contains letters or digits, and is non-null

isAlphanumericSpace

public static boolean isAlphanumericSpace(String str)

Checks if the String contains only unicode letters, digits or space (' ').

null will return false. An empty String ("") will return true.

 StringUtils.isAlphanumeric(null)   = false
 StringUtils.isAlphanumeric("")     = true
 StringUtils.isAlphanumeric("  ")   = true
 StringUtils.isAlphanumeric("abc")  = true
 StringUtils.isAlphanumeric("ab c") = true
 StringUtils.isAlphanumeric("ab2c") = true
 StringUtils.isAlphanumeric("ab-c") = false
 

Parameters: str the String to check, may be null

Returns: true if only contains letters, digits or space, and is non-null

isAlphaSpace

public static boolean isAlphaSpace(String str)

Checks if the String contains only unicode letters and space (' ').

null will return false An empty String ("") will return true.

 StringUtils.isAlphaSpace(null)   = false
 StringUtils.isAlphaSpace("")     = true
 StringUtils.isAlphaSpace("  ")   = true
 StringUtils.isAlphaSpace("abc")  = true
 StringUtils.isAlphaSpace("ab c") = true
 StringUtils.isAlphaSpace("ab2c") = false
 StringUtils.isAlphaSpace("ab-c") = false
 

Parameters: str the String to check, may be null

Returns: true if only contains letters and space, and is non-null

isAsciiPrintable

public static boolean isAsciiPrintable(String str)

Checks if the string contains only ASCII printable characters.

null will return false. An empty String ("") will return true.

 StringUtils.isAsciiPrintable(null)     = false
 StringUtils.isAsciiPrintable("")       = true
 StringUtils.isAsciiPrintable(" ")      = true
 StringUtils.isAsciiPrintable("Ceki")   = true
 StringUtils.isAsciiPrintable("ab2c")   = true
 StringUtils.isAsciiPrintable("!ab-c~") = true
 StringUtils.isAsciiPrintable(" ") = true
 StringUtils.isAsciiPrintable("!") = true
 StringUtils.isAsciiPrintable("~") = true
 StringUtils.isAsciiPrintable("") = false
 StringUtils.isAsciiPrintable("Ceki Gülcü") = false
 

Parameters: str the string to check, may be null

Returns: true if every character is in the range 32 thru 126

Since: 2.1

isBlank

public static boolean isBlank(String str)

Checks if a String is whitespace, empty ("") or null.

 StringUtils.isBlank(null)      = true
 StringUtils.isBlank("")        = true
 StringUtils.isBlank(" ")       = true
 StringUtils.isBlank("bob")     = false
 StringUtils.isBlank("  bob  ") = false
 

Parameters: str the String to check, may be null

Returns: true if the String is null, empty or whitespace

Since: 2.0

isEmpty

public static boolean isEmpty(String str)

Checks if a String is empty ("") or null.

 StringUtils.isEmpty(null)      = true
 StringUtils.isEmpty("")        = true
 StringUtils.isEmpty(" ")       = false
 StringUtils.isEmpty("bob")     = false
 StringUtils.isEmpty("  bob  ") = false
 

NOTE: This method changed in Lang version 2.0. It no longer trims the String. That functionality is available in isBlank().

Parameters: str the String to check, may be null

Returns: true if the String is empty or null

isNotBlank

public static boolean isNotBlank(String str)

Checks if a String is not empty (""), not null and not whitespace only.

 StringUtils.isNotBlank(null)      = false
 StringUtils.isNotBlank("")        = false
 StringUtils.isNotBlank(" ")       = false
 StringUtils.isNotBlank("bob")     = true
 StringUtils.isNotBlank("  bob  ") = true
 

Parameters: str the String to check, may be null

Returns: true if the String is not empty and not null and not whitespace

Since: 2.0

isNotEmpty

public static boolean isNotEmpty(String str)

Checks if a String is not empty ("") and not null.

 StringUtils.isNotEmpty(null)      = false
 StringUtils.isNotEmpty("")        = false
 StringUtils.isNotEmpty(" ")       = true
 StringUtils.isNotEmpty("bob")     = true
 StringUtils.isNotEmpty("  bob  ") = true
 

Parameters: str the String to check, may be null

Returns: true if the String is not empty and not null

isNumeric

public static boolean isNumeric(String str)

Checks if the String contains only unicode digits. A decimal point is not a unicode digit and returns false.

null will return false. An empty String ("") will return true.

 StringUtils.isNumeric(null)   = false
 StringUtils.isNumeric("")     = true
 StringUtils.isNumeric("  ")   = false
 StringUtils.isNumeric("123")  = true
 StringUtils.isNumeric("12 3") = false
 StringUtils.isNumeric("ab2c") = false
 StringUtils.isNumeric("12-3") = false
 StringUtils.isNumeric("12.3") = false
 

Parameters: str the String to check, may be null

Returns: true if only contains digits, and is non-null

isNumericSpace

public static boolean isNumericSpace(String str)

Checks if the String contains only unicode digits or space (' '). A decimal point is not a unicode digit and returns false.

null will return false. An empty String ("") will return true.

 StringUtils.isNumeric(null)   = false
 StringUtils.isNumeric("")     = true
 StringUtils.isNumeric("  ")   = true
 StringUtils.isNumeric("123")  = true
 StringUtils.isNumeric("12 3") = true
 StringUtils.isNumeric("ab2c") = false
 StringUtils.isNumeric("12-3") = false
 StringUtils.isNumeric("12.3") = false
 

Parameters: str the String to check, may be null

Returns: true if only contains digits or space, and is non-null

isWhitespace

public static boolean isWhitespace(String str)

Checks if the String contains only whitespace.

null will return false. An empty String ("") will return true.

 StringUtils.isWhitespace(null)   = false
 StringUtils.isWhitespace("")     = true
 StringUtils.isWhitespace("  ")   = true
 StringUtils.isWhitespace("abc")  = false
 StringUtils.isWhitespace("ab2c") = false
 StringUtils.isWhitespace("ab-c") = false
 

Parameters: str the String to check, may be null

Returns: true if only contains whitespace, and is non-null

Since: 2.0

join

public static String join(Object[] array)

Joins the elements of the provided array into a single String containing the provided list of elements.

No separator is added to the joined String. Null objects or empty strings within the array are represented by empty strings.

 StringUtils.join(null)            = null
 StringUtils.join([])              = ""
 StringUtils.join([null])          = ""
 StringUtils.join(["a", "b", "c"]) = "abc"
 StringUtils.join([null, "", "a"]) = "a"
 

Parameters: array the array of values to join together, may be null

Returns: the joined String, null if null array input

Since: 2.0

join

public static String join(Object[] array, char separator)

Joins the elements of the provided array into a single String containing the provided list of elements.

No delimiter is added before or after the list. Null objects or empty strings within the array are represented by empty strings.

 StringUtils.join(null, *)               = null
 StringUtils.join([], *)                 = ""
 StringUtils.join([null], *)             = ""
 StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
 StringUtils.join(["a", "b", "c"], null) = "abc"
 StringUtils.join([null, "", "a"], ';')  = ";;a"
 

Parameters: array the array of values to join together, may be null separator the separator character to use

Returns: the joined String, null if null array input

Since: 2.0

join

public static String join(Object[] array, String separator)

Joins the elements of the provided array into a single String containing the provided list of elements.

No delimiter is added before or after the list. A null separator is the same as an empty String (""). Null objects or empty strings within the array are represented by empty strings.

 StringUtils.join(null, *)                = null
 StringUtils.join([], *)                  = ""
 StringUtils.join([null], *)              = ""
 StringUtils.join(["a", "b", "c"], "--")  = "a--b--c"
 StringUtils.join(["a", "b", "c"], null)  = "abc"
 StringUtils.join(["a", "b", "c"], "")    = "abc"
 StringUtils.join([null, "", "a"], ',')   = ",,a"
 

Parameters: array the array of values to join together, may be null separator the separator character to use, null treated as ""

Returns: the joined String, null if null array input

join

public static String join(Iterator iterator, char separator)

Joins the elements of the provided Iterator into a single String containing the provided elements.

No delimiter is added before or after the list. Null objects or empty strings within the iteration are represented by empty strings.

See the examples here: {@link #join(Object[],char)}.

Parameters: iterator the Iterator of values to join together, may be null separator the separator character to use

Returns: the joined String, null if null iterator input

Since: 2.0

join

public static String join(Iterator iterator, String separator)

Joins the elements of the provided Iterator into a single String containing the provided elements.

No delimiter is added before or after the list. A null separator is the same as an empty String ("").

See the examples here: {@link #join(Object[],String)}.

Parameters: iterator the Iterator of values to join together, may be null separator the separator character to use, null treated as ""

Returns: the joined String, null if null iterator input

lastIndexOf

public static int lastIndexOf(String str, char searchChar)

Finds the last index within a String, handling null. This method uses {@link String#lastIndexOf(int)}.

A null or empty ("") String will return -1.

 StringUtils.lastIndexOf(null, *)         = -1
 StringUtils.lastIndexOf("", *)           = -1
 StringUtils.lastIndexOf("aabaabaa", 'a') = 7
 StringUtils.lastIndexOf("aabaabaa", 'b') = 5
 

Parameters: str the String to check, may be null searchChar the character to find

Returns: the last index of the search character, -1 if no match or null string input

Since: 2.0

lastIndexOf

public static int lastIndexOf(String str, char searchChar, int startPos)

Finds the last index within a String from a start position, handling null. This method uses {@link String#lastIndexOf(int, int)}.

A null or empty ("") String will return -1. A negative start position returns -1. A start position greater than the string length searches the whole string.

 StringUtils.lastIndexOf(null, *, *)          = -1
 StringUtils.lastIndexOf("", *,  *)           = -1
 StringUtils.lastIndexOf("aabaabaa", 'b', 8)  = 5
 StringUtils.lastIndexOf("aabaabaa", 'b', 4)  = 2
 StringUtils.lastIndexOf("aabaabaa", 'b', 0)  = -1
 StringUtils.lastIndexOf("aabaabaa", 'b', 9)  = 5
 StringUtils.lastIndexOf("aabaabaa", 'b', -1) = -1
 StringUtils.lastIndexOf("aabaabaa", 'a', 0)  = 0
 

Parameters: str the String to check, may be null searchChar the character to find startPos the start position

Returns: the last index of the search character, -1 if no match or null string input

Since: 2.0

lastIndexOf

public static int lastIndexOf(String str, String searchStr)

Finds the last index within a String, handling null. This method uses {@link String#lastIndexOf(String)}.

A null String will return -1.

 StringUtils.lastIndexOf(null, *)          = -1
 StringUtils.lastIndexOf(*, null)          = -1
 StringUtils.lastIndexOf("", "")           = 0
 StringUtils.lastIndexOf("aabaabaa", "a")  = 0
 StringUtils.lastIndexOf("aabaabaa", "b")  = 2
 StringUtils.lastIndexOf("aabaabaa", "ab") = 1
 StringUtils.lastIndexOf("aabaabaa", "")   = 8
 

Parameters: str the String to check, may be null searchStr the String to find, may be null

Returns: the last index of the search String, -1 if no match or null string input

Since: 2.0

lastIndexOf

public static int lastIndexOf(String str, String searchStr, int startPos)

Finds the first index within a String, handling null. This method uses {@link String#lastIndexOf(String, int)}.

A null String will return -1. A negative start position returns -1. An empty ("") search String always matches unless the start position is negative. A start position greater than the string length searches the whole string.

 StringUtils.lastIndexOf(null, *, *)          = -1
 StringUtils.lastIndexOf(*, null, *)          = -1
 StringUtils.lastIndexOf("aabaabaa", "a", 8)  = 7
 StringUtils.lastIndexOf("aabaabaa", "b", 8)  = 5
 StringUtils.lastIndexOf("aabaabaa", "ab", 8) = 4
 StringUtils.lastIndexOf("aabaabaa", "b", 9)  = 5
 StringUtils.lastIndexOf("aabaabaa", "b", -1) = -1
 StringUtils.lastIndexOf("aabaabaa", "a", 0)  = 0
 StringUtils.lastIndexOf("aabaabaa", "b", 0)  = -1
 

Parameters: str the String to check, may be null searchStr the String to find, may be null startPos the start position, negative treated as zero

Returns: the first index of the search String, -1 if no match or null string input

Since: 2.0

lastIndexOfAny

public static int lastIndexOfAny(String str, String[] searchStrs)

Find the latest index of any of a set of potential substrings.

A null String will return -1. A null search array will return -1. A null or zero length search array entry will be ignored, but a search array containing "" will return the length of str if str is not null. This method uses {@link String#indexOf(String)}

 StringUtils.lastIndexOfAny(null, *)                   = -1
 StringUtils.lastIndexOfAny(*, null)                   = -1
 StringUtils.lastIndexOfAny(*, [])                     = -1
 StringUtils.lastIndexOfAny(*, [null])                 = -1
 StringUtils.lastIndexOfAny("zzabyycdxx", ["ab","cd"]) = 6
 StringUtils.lastIndexOfAny("zzabyycdxx", ["cd","ab"]) = 6
 StringUtils.lastIndexOfAny("zzabyycdxx", ["mn","op"]) = -1
 StringUtils.lastIndexOfAny("zzabyycdxx", ["mn","op"]) = -1
 StringUtils.lastIndexOfAny("zzabyycdxx", ["mn",""])   = 10
 

Parameters: str the String to check, may be null searchStrs the Strings to search for, may be null

Returns: the last index of any of the Strings, -1 if no match

left

public static String left(String str, int len)

Gets the leftmost len characters of a String.

If len characters are not available, or the String is null, the String will be returned without an exception. An exception is thrown if len is negative.

 StringUtils.left(null, *)    = null
 StringUtils.left(*, -ve)     = ""
 StringUtils.left("", *)      = ""
 StringUtils.left("abc", 0)   = ""
 StringUtils.left("abc", 2)   = "ab"
 StringUtils.left("abc", 4)   = "abc"
 

Parameters: str the String to get the leftmost characters from, may be null len the length of the required String, must be zero or positive

Returns: the leftmost characters, null if null String input

leftPad

public static String leftPad(String str, int size)

Left pad a String with spaces (' ').

The String is padded to the size of size.

 StringUtils.leftPad(null, *)   = null
 StringUtils.leftPad("", 3)     = "   "
 StringUtils.leftPad("bat", 3)  = "bat"
 StringUtils.leftPad("bat", 5)  = "  bat"
 StringUtils.leftPad("bat", 1)  = "bat"
 StringUtils.leftPad("bat", -1) = "bat"
 

Parameters: str the String to pad out, may be null size the size to pad to

Returns: left padded String or original String if no padding is necessary, null if null String input

leftPad

public static String leftPad(String str, int size, char padChar)

Left pad a String with a specified character.

Pad to a size of size.

 StringUtils.leftPad(null, *, *)     = null
 StringUtils.leftPad("", 3, 'z')     = "zzz"
 StringUtils.leftPad("bat", 3, 'z')  = "bat"
 StringUtils.leftPad("bat", 5, 'z')  = "zzbat"
 StringUtils.leftPad("bat", 1, 'z')  = "bat"
 StringUtils.leftPad("bat", -1, 'z') = "bat"
 

Parameters: str the String to pad out, may be null size the size to pad to padChar the character to pad with

Returns: left padded String or original String if no padding is necessary, null if null String input

Since: 2.0

leftPad

public static String leftPad(String str, int size, String padStr)

Left pad a String with a specified String.

Pad to a size of size.

 StringUtils.leftPad(null, *, *)      = null
 StringUtils.leftPad("", 3, "z")      = "zzz"
 StringUtils.leftPad("bat", 3, "yz")  = "bat"
 StringUtils.leftPad("bat", 5, "yz")  = "yzbat"
 StringUtils.leftPad("bat", 8, "yz")  = "yzyzybat"
 StringUtils.leftPad("bat", 1, "yz")  = "bat"
 StringUtils.leftPad("bat", -1, "yz") = "bat"
 StringUtils.leftPad("bat", 5, null)  = "  bat"
 StringUtils.leftPad("bat", 5, "")    = "  bat"
 

Parameters: str the String to pad out, may be null size the size to pad to padStr the String to pad with, null or empty treated as single space

Returns: left padded String or original String if no padding is necessary, null if null String input

lowerCase

public static String lowerCase(String str)

Converts a String to lower case as per {@link String#toLowerCase()}.

A null input String returns null.

 StringUtils.lowerCase(null)  = null
 StringUtils.lowerCase("")    = ""
 StringUtils.lowerCase("aBc") = "abc"
 

Parameters: str the String to lower case, may be null

Returns: the lower cased String, null if null String input

mid

public static String mid(String str, int pos, int len)

Gets len characters from the middle of a String.

If len characters are not available, the remainder of the String will be returned without an exception. If the String is null, null will be returned. An exception is thrown if len is negative.

 StringUtils.mid(null, *, *)    = null
 StringUtils.mid(*, *, -ve)     = ""
 StringUtils.mid("", 0, *)      = ""
 StringUtils.mid("abc", 0, 2)   = "ab"
 StringUtils.mid("abc", 0, 4)   = "abc"
 StringUtils.mid("abc", 2, 4)   = "c"
 StringUtils.mid("abc", 4, 2)   = ""
 StringUtils.mid("abc", -2, 2)  = "ab"
 

Parameters: str the String to get the characters from, may be null pos the position to start from, negative treated as zero len the length of the required String, must be zero or positive

Returns: the middle characters, null if null String input

ordinalIndexOf

public static int ordinalIndexOf(String str, String searchStr, int ordinal)

Finds the n-th index within a String, handling null. This method uses {@link String#indexOf(String)}.

A null String will return -1.

 StringUtils.ordinalIndexOf(null, *, *)          = -1
 StringUtils.ordinalIndexOf(*, null, *)          = -1
 StringUtils.ordinalIndexOf("", "", *)           = 0
 StringUtils.ordinalIndexOf("aabaabaa", "a", 1)  = 0
 StringUtils.ordinalIndexOf("aabaabaa", "a", 2)  = 1
 StringUtils.ordinalIndexOf("aabaabaa", "b", 1)  = 2
 StringUtils.ordinalIndexOf("aabaabaa", "b", 2)  = 5
 StringUtils.ordinalIndexOf("aabaabaa", "ab", 1) = 1
 StringUtils.ordinalIndexOf("aabaabaa", "ab", 2) = 4
 StringUtils.ordinalIndexOf("aabaabaa", "", 1)   = 0
 StringUtils.ordinalIndexOf("aabaabaa", "", 2)   = 0
 

Parameters: str the String to check, may be null searchStr the String to find, may be null ordinal the n-th searchStr to find

Returns: the n-th index of the search String, -1 (INDEX_NOT_FOUND) if no match or null string input

Since: 2.1

overlay

public static String overlay(String str, String overlay, int start, int end)

Overlays part of a String with another String.

A null string input returns null. A negative index is treated as zero. An index greater than the string length is treated as the string length. The start index is always the smaller of the two indices.

 StringUtils.overlay(null, *, *, *)            = null
 StringUtils.overlay("", "abc", 0, 0)          = "abc"
 StringUtils.overlay("abcdef", null, 2, 4)     = "abef"
 StringUtils.overlay("abcdef", "", 2, 4)       = "abef"
 StringUtils.overlay("abcdef", "", 4, 2)       = "abef"
 StringUtils.overlay("abcdef", "zzzz", 2, 4)   = "abzzzzef"
 StringUtils.overlay("abcdef", "zzzz", 4, 2)   = "abzzzzef"
 StringUtils.overlay("abcdef", "zzzz", -1, 4)  = "zzzzef"
 StringUtils.overlay("abcdef", "zzzz", 2, 8)   = "abzzzz"
 StringUtils.overlay("abcdef", "zzzz", -2, -3) = "zzzzabcdef"
 StringUtils.overlay("abcdef", "zzzz", 8, 10)  = "abcdefzzzz"
 

Parameters: str the String to do overlaying in, may be null overlay the String to overlay, may be null start the position to start overlaying at end the position to stop overlaying before

Returns: overlayed String, null if null String input

Since: 2.0

overlayString

public static String overlayString(String text, String overlay, int start, int end)

Deprecated: Use better named {@link #overlay(String, String, int, int)} instead. Method will be removed in Commons Lang 3.0.

Overlays part of a String with another String.

 StringUtils.overlayString(null, *, *, *)           = NullPointerException
 StringUtils.overlayString(*, null, *, *)           = NullPointerException
 StringUtils.overlayString("", "abc", 0, 0)         = "abc"
 StringUtils.overlayString("abcdef", null, 2, 4)    = "abef"
 StringUtils.overlayString("abcdef", "", 2, 4)      = "abef"
 StringUtils.overlayString("abcdef", "zzzz", 2, 4)  = "abzzzzef"
 StringUtils.overlayString("abcdef", "zzzz", 4, 2)  = "abcdzzzzcdef"
 StringUtils.overlayString("abcdef", "zzzz", -1, 4) = IndexOutOfBoundsException
 StringUtils.overlayString("abcdef", "zzzz", 2, 8)  = IndexOutOfBoundsException
 

Parameters: text the String to do overlaying in, may be null overlay the String to overlay, may be null start the position to start overlaying at, must be valid end the position to stop overlaying before, must be valid

Returns: overlayed String, null if null String input

Throws: NullPointerException if text or overlay is null IndexOutOfBoundsException if either position is invalid

prechomp

public static String prechomp(String str, String sep)

Deprecated: Use {@link #substringAfter(String,String)} instead. Method will be removed in Commons Lang 3.0.

Remove the first value of a supplied String, and everything before it from a String.

Parameters: str the String to chomp from, must not be null sep the String to chomp, must not be null

Returns: String without chomped beginning

Throws: NullPointerException if str or sep is null

remove

public static String remove(String str, String remove)

Removes all occurances of a substring from within the source string.

A null source string will return null. An empty ("") source string will return the empty string. A null remove string will return the source string. An empty ("") remove string will return the source string.

 StringUtils.remove(null, *)        = null
 StringUtils.remove("", *)          = ""
 StringUtils.remove(*, null)        = *
 StringUtils.remove(*, "")          = *
 StringUtils.remove("queued", "ue") = "qd"
 StringUtils.remove("queued", "zz") = "queued"
 

Parameters: str the source String to search, may be null remove the String to search for and remove, may be null

Returns: the substring with the string removed if found, null if null String input

Since: 2.1

remove

public static String remove(String str, char remove)

Removes all occurances of a character from within the source string.

A null source string will return null. An empty ("") source string will return the empty string.

 StringUtils.remove(null, *)       = null
 StringUtils.remove("", *)         = ""
 StringUtils.remove("queued", 'u') = "qeed"
 StringUtils.remove("queued", 'z') = "queued"
 

Parameters: str the source String to search, may be null remove the char to search for and remove, may be null

Returns: the substring with the char removed if found, null if null String input

Since: 2.1

removeEnd

public static String removeEnd(String str, String remove)

Removes a substring only if it is at the end of a source string, otherwise returns the source string.

A null source string will return null. An empty ("") source string will return the empty string. A null search string will return the source string.

 StringUtils.removeEnd(null, *)      = null
 StringUtils.removeEnd("", *)        = ""
 StringUtils.removeEnd(*, null)      = *
 StringUtils.removeEnd("www.domain.com", ".com.")  = "www,domain"
 StringUtils.removeEnd("www.domain.com", ".com")   = "www.domain"
 StringUtils.removeEnd("www.domain.com", "domain") = "www.domain.com"
 StringUtils.removeEnd("abc", "")    = "abc"
 

Parameters: str the source String to search, may be null remove the String to search for and remove, may be null

Returns: the substring with the string removed if found, null if null String input

Since: 2.1

removeStart

public static String removeStart(String str, String remove)

Removes a substring only if it is at the begining of a source string, otherwise returns the source string.

A null source string will return null. An empty ("") source string will return the empty string. A null search string will return the source string.

 StringUtils.removeStart(null, *)      = null
 StringUtils.removeStart("", *)        = ""
 StringUtils.removeStart(*, null)      = *
 StringUtils.removeStart("www.domain.com", "www.")   = "domain.com"
 StringUtils.removeStart("domain.com", "www.")       = "domain.com"
 StringUtils.removeStart("www.domain.com", "domain") = "www.domain.com"
 StringUtils.removeStart("abc", "")    = "abc"
 

Parameters: str the source String to search, may be null remove the String to search for and remove, may be null

Returns: the substring with the string removed if found, null if null String input

Since: 2.1

repeat

public static String repeat(String str, int repeat)

Repeat a String repeat times to form a new String.

 StringUtils.repeat(null, 2) = null
 StringUtils.repeat("", 0)   = ""
 StringUtils.repeat("", 2)   = ""
 StringUtils.repeat("a", 3)  = "aaa"
 StringUtils.repeat("ab", 2) = "abab"
 StringUtils.repeat("a", -2) = ""
 

Parameters: str the String to repeat, may be null repeat number of times to repeat str, negative treated as zero

Returns: a new String consisting of the original String repeated, null if null String input

replace

public static String replace(String text, String repl, String with)

Replaces all occurrences of a String within another String.

A null reference passed to this method is a no-op.

 StringUtils.replace(null, *, *)        = null
 StringUtils.replace("", *, *)          = ""
 StringUtils.replace("any", null, *)    = "any"
 StringUtils.replace("any", *, null)    = "any"
 StringUtils.replace("any", "", *)      = "any"
 StringUtils.replace("aba", "a", null)  = "aba"
 StringUtils.replace("aba", "a", "")    = "b"
 StringUtils.replace("aba", "a", "z")   = "zbz"
 

Parameters: text text to search and replace in, may be null repl the String to search for, may be null with the String to replace with, may be null

Returns: the text with any replacements processed, null if null String input

See Also: StringUtils

replace

public static String replace(String text, String repl, String with, int max)

Replaces a String with another String inside a larger String, for the first max values of the search String.

A null reference passed to this method is a no-op.

 StringUtils.replace(null, *, *, *)         = null
 StringUtils.replace("", *, *, *)           = ""
 StringUtils.replace("any", null, *, *)     = "any"
 StringUtils.replace("any", *, null, *)     = "any"
 StringUtils.replace("any", "", *, *)       = "any"
 StringUtils.replace("any", *, *, 0)        = "any"
 StringUtils.replace("abaa", "a", null, -1) = "abaa"
 StringUtils.replace("abaa", "a", "", -1)   = "b"
 StringUtils.replace("abaa", "a", "z", 0)   = "abaa"
 StringUtils.replace("abaa", "a", "z", 1)   = "zbaa"
 StringUtils.replace("abaa", "a", "z", 2)   = "zbza"
 StringUtils.replace("abaa", "a", "z", -1)  = "zbzz"
 

Parameters: text text to search and replace in, may be null repl the String to search for, may be null with the String to replace with, may be null max maximum number of values to replace, or -1 if no maximum

Returns: the text with any replacements processed, null if null String input

replaceChars

public static String replaceChars(String str, char searchChar, char replaceChar)

Replaces all occurrences of a character in a String with another. This is a null-safe version of {@link String#replace(char, char)}.

A null string input returns null. An empty ("") string input returns an empty string.

 StringUtils.replaceChars(null, *, *)        = null
 StringUtils.replaceChars("", *, *)          = ""
 StringUtils.replaceChars("abcba", 'b', 'y') = "aycya"
 StringUtils.replaceChars("abcba", 'z', 'y') = "abcba"
 

Parameters: str String to replace characters in, may be null searchChar the character to search for, may be null replaceChar the character to replace, may be null

Returns: modified String, null if null string input

Since: 2.0

replaceChars

public static String replaceChars(String str, String searchChars, String replaceChars)

Replaces multiple characters in a String in one go. This method can also be used to delete characters.

For example:
replaceChars("hello", "ho", "jy") = jelly.

A null string input returns null. An empty ("") string input returns an empty string. A null or empty set of search characters returns the input string.

The length of the search characters should normally equal the length of the replace characters. If the search characters is longer, then the extra search characters are deleted. If the search characters is shorter, then the extra replace characters are ignored.

 StringUtils.replaceChars(null, *, *)           = null
 StringUtils.replaceChars("", *, *)             = ""
 StringUtils.replaceChars("abc", null, *)       = "abc"
 StringUtils.replaceChars("abc", "", *)         = "abc"
 StringUtils.replaceChars("abc", "b", null)     = "ac"
 StringUtils.replaceChars("abc", "b", "")       = "ac"
 StringUtils.replaceChars("abcba", "bc", "yz")  = "ayzya"
 StringUtils.replaceChars("abcba", "bc", "y")   = "ayya"
 StringUtils.replaceChars("abcba", "bc", "yzx") = "ayzya"
 

Parameters: str String to replace characters in, may be null searchChars a set of characters to search for, may be null replaceChars a set of characters to replace, may be null

Returns: modified String, null if null string input

Since: 2.0

replaceOnce

public static String replaceOnce(String text, String repl, String with)

Replaces a String with another String inside a larger String, once.

A null reference passed to this method is a no-op.

 StringUtils.replaceOnce(null, *, *)        = null
 StringUtils.replaceOnce("", *, *)          = ""
 StringUtils.replaceOnce("any", null, *)    = "any"
 StringUtils.replaceOnce("any", *, null)    = "any"
 StringUtils.replaceOnce("any", "", *)      = "any"
 StringUtils.replaceOnce("aba", "a", null)  = "aba"
 StringUtils.replaceOnce("aba", "a", "")    = "ba"
 StringUtils.replaceOnce("aba", "a", "z")   = "zba"
 

Parameters: text text to search and replace in, may be null repl the String to search for, may be null with the String to replace with, may be null

Returns: the text with any replacements processed, null if null String input

See Also: StringUtils

reverse

public static String reverse(String str)

Reverses a String as per {@link StringBuffer#reverse()}.

A null String returns null.

 StringUtils.reverse(null)  = null
 StringUtils.reverse("")    = ""
 StringUtils.reverse("bat") = "tab"
 

Parameters: str the String to reverse, may be null

Returns: the reversed String, null if null String input

reverseDelimited

public static String reverseDelimited(String str, char separatorChar)

Reverses a String that is delimited by a specific character.

The Strings between the delimiters are not reversed. Thus java.lang.String becomes String.lang.java (if the delimiter is '.').

 StringUtils.reverseDelimited(null, *)      = null
 StringUtils.reverseDelimited("", *)        = ""
 StringUtils.reverseDelimited("a.b.c", 'x') = "a.b.c"
 StringUtils.reverseDelimited("a.b.c", ".") = "c.b.a"
 

Parameters: str the String to reverse, may be null separatorChar the separator character to use

Returns: the reversed String, null if null String input

Since: 2.0

reverseDelimitedString

public static String reverseDelimitedString(String str, String separatorChars)

Deprecated: Use {@link #reverseDelimited(String, char)} instead. This method is broken as the join doesn't know which char to use. Method will be removed in Commons Lang 3.0.

Reverses a String that is delimited by a specific character.

The Strings between the delimiters are not reversed. Thus java.lang.String becomes String.lang.java (if the delimiter is ".").

 StringUtils.reverseDelimitedString(null, *)       = null
 StringUtils.reverseDelimitedString("",*)          = ""
 StringUtils.reverseDelimitedString("a.b.c", null) = "a.b.c"
 StringUtils.reverseDelimitedString("a.b.c", ".")  = "c.b.a"
 

Parameters: str the String to reverse, may be null separatorChars the separator characters to use, null treated as whitespace

Returns: the reversed String, null if null String input

right

public static String right(String str, int len)

Gets the rightmost len characters of a String.

If len characters are not available, or the String is null, the String will be returned without an an exception. An exception is thrown if len is negative.

 StringUtils.right(null, *)    = null
 StringUtils.right(*, -ve)     = ""
 StringUtils.right("", *)      = ""
 StringUtils.right("abc", 0)   = ""
 StringUtils.right("abc", 2)   = "bc"
 StringUtils.right("abc", 4)   = "abc"
 

Parameters: str the String to get the rightmost characters from, may be null len the length of the required String, must be zero or positive

Returns: the rightmost characters, null if null String input

rightPad

public static String rightPad(String str, int size)

Right pad a String with spaces (' ').

The String is padded to the size of size.

 StringUtils.rightPad(null, *)   = null
 StringUtils.rightPad("", 3)     = "   "
 StringUtils.rightPad("bat", 3)  = "bat"
 StringUtils.rightPad("bat", 5)  = "bat  "
 StringUtils.rightPad("bat", 1)  = "bat"
 StringUtils.rightPad("bat", -1) = "bat"
 

Parameters: str the String to pad out, may be null size the size to pad to

Returns: right padded String or original String if no padding is necessary, null if null String input

rightPad

public static String rightPad(String str, int size, char padChar)

Right pad a String with a specified character.

The String is padded to the size of size.

 StringUtils.rightPad(null, *, *)     = null
 StringUtils.rightPad("", 3, 'z')     = "zzz"
 StringUtils.rightPad("bat", 3, 'z')  = "bat"
 StringUtils.rightPad("bat", 5, 'z')  = "batzz"
 StringUtils.rightPad("bat", 1, 'z')  = "bat"
 StringUtils.rightPad("bat", -1, 'z') = "bat"
 

Parameters: str the String to pad out, may be null size the size to pad to padChar the character to pad with

Returns: right padded String or original String if no padding is necessary, null if null String input

Since: 2.0

rightPad

public static String rightPad(String str, int size, String padStr)

Right pad a String with a specified String.

The String is padded to the size of size.

 StringUtils.rightPad(null, *, *)      = null
 StringUtils.rightPad("", 3, "z")      = "zzz"
 StringUtils.rightPad("bat", 3, "yz")  = "bat"
 StringUtils.rightPad("bat", 5, "yz")  = "batyz"
 StringUtils.rightPad("bat", 8, "yz")  = "batyzyzy"
 StringUtils.rightPad("bat", 1, "yz")  = "bat"
 StringUtils.rightPad("bat", -1, "yz") = "bat"
 StringUtils.rightPad("bat", 5, null)  = "bat  "
 StringUtils.rightPad("bat", 5, "")    = "bat  "
 

Parameters: str the String to pad out, may be null size the size to pad to padStr the String to pad with, null or empty treated as single space

Returns: right padded String or original String if no padding is necessary, null if null String input

split

public static String[] split(String str)

Splits the provided text into an array, using whitespace as the separator. Whitespace is defined by {@link Character#isWhitespace(char)}.

The separator is not included in the returned String array. Adjacent separators are treated as one separator. For more control over the split use the StrTokenizer class.

A null input String returns null.

 StringUtils.split(null)       = null
 StringUtils.split("")         = []
 StringUtils.split("abc def")  = ["abc", "def"]
 StringUtils.split("abc  def") = ["abc", "def"]
 StringUtils.split(" abc ")    = ["abc"]
 

Parameters: str the String to parse, may be null

Returns: an array of parsed Strings, null if null String input

split

public static String[] split(String str, char separatorChar)

Splits the provided text into an array, separator specified. This is an alternative to using StringTokenizer.

The separator is not included in the returned String array. Adjacent separators are treated as one separator. For more control over the split use the StrTokenizer class.

A null input String returns null.

 StringUtils.split(null, *)         = null
 StringUtils.split("", *)           = []
 StringUtils.split("a.b.c", '.')    = ["a", "b", "c"]
 StringUtils.split("a..b.c", '.')   = ["a", "b", "c"]
 StringUtils.split("a:b:c", '.')    = ["a:b:c"]
 StringUtils.split("a\tb\nc", null) = ["a", "b", "c"]
 StringUtils.split("a b c", ' ')    = ["a", "b", "c"]
 

Parameters: str the String to parse, may be null separatorChar the character used as the delimiter, null splits on whitespace

Returns: an array of parsed Strings, null if null String input

Since: 2.0

split

public static String[] split(String str, String separatorChars)

Splits the provided text into an array, separators specified. This is an alternative to using StringTokenizer.

The separator is not included in the returned String array. Adjacent separators are treated as one separator. For more control over the split use the StrTokenizer class.

A null input String returns null. A null separatorChars splits on whitespace.

 StringUtils.split(null, *)         = null
 StringUtils.split("", *)           = []
 StringUtils.split("abc def", null) = ["abc", "def"]
 StringUtils.split("abc def", " ")  = ["abc", "def"]
 StringUtils.split("abc  def", " ") = ["abc", "def"]
 StringUtils.split("ab:cd:ef", ":") = ["ab", "cd", "ef"]
 

Parameters: str the String to parse, may be null separatorChars the characters used as the delimiters, null splits on whitespace

Returns: an array of parsed Strings, null if null String input

split

public static String[] split(String str, String separatorChars, int max)

Splits the provided text into an array with a maximum length, separators specified.

The separator is not included in the returned String array. Adjacent separators are treated as one separator.

A null input String returns null. A null separatorChars splits on whitespace.

If more than max delimited substrings are found, the last returned string includes all characters after the first max - 1 returned strings (including separator characters).

 StringUtils.split(null, *, *)            = null
 StringUtils.split("", *, *)              = []
 StringUtils.split("ab de fg", null, 0)   = ["ab", "cd", "ef"]
 StringUtils.split("ab   de fg", null, 0) = ["ab", "cd", "ef"]
 StringUtils.split("ab:cd:ef", ":", 0)    = ["ab", "cd", "ef"]
 StringUtils.split("ab:cd:ef", ":", 2)    = ["ab", "cd:ef"]
 

Parameters: str the String to parse, may be null separatorChars the characters used as the delimiters, null splits on whitespace max the maximum number of elements to include in the array. A zero or negative value implies no limit

Returns: an array of parsed Strings, null if null String input

splitByWholeSeparator

public static String[] splitByWholeSeparator(String str, String separator)

Splits the provided text into an array, separator string specified.

The separator(s) will not be included in the returned String array. Adjacent separators are treated as one separator.

A null input String returns null. A null separator splits on whitespace.

 StringUtils.split(null, *)            = null
 StringUtils.split("", *)              = []
 StringUtils.split("ab de fg", null)   = ["ab", "de", "fg"]
 StringUtils.split("ab   de fg", null) = ["ab", "de", "fg"]
 StringUtils.split("ab:cd:ef", ":")    = ["ab", "cd", "ef"]
 StringUtils.split("abstemiouslyaeiouyabstemiously", "aeiouy")  = ["bst", "m", "sl", "bst", "m", "sl"]
 StringUtils.split("abstemiouslyaeiouyabstemiously", "aeiouy")  = ["abstemiously", "abstemiously"]
 

Parameters: str the String to parse, may be null separator String containing the String to be used as a delimiter, null splits on whitespace

Returns: an array of parsed Strings, null if null String was input

splitByWholeSeparator

public static String[] splitByWholeSeparator(String str, String separator, int max)

Splits the provided text into an array, separator string specified. Returns a maximum of max substrings.

The separator(s) will not be included in the returned String array. Adjacent separators are treated as one separator.

A null input String returns null. A null separator splits on whitespace.

 StringUtils.splitByWholeSeparator(null, *, *)               = null
 StringUtils.splitByWholeSeparator("", *, *)                 = []
 StringUtils.splitByWholeSeparator("ab de fg", null, 0)      = ["ab", "de", "fg"]
 StringUtils.splitByWholeSeparator("ab   de fg", null, 0)    = ["ab", "de", "fg"]
 StringUtils.splitByWholeSeparator("ab:cd:ef", ":", 2)       = ["ab", "cd"]
 StringUtils.splitByWholeSeparator("abstemiouslyaeiouyabstemiously", "aeiouy", 2) = ["bst", "m"]
 StringUtils.splitByWholeSeparator("abstemiouslyaeiouyabstemiously", "aeiouy", 2)  = ["abstemiously", "abstemiously"]
 

Parameters: str the String to parse, may be null separator String containing the String to be used as a delimiter, null splits on whitespace max the maximum number of elements to include in the returned array. A zero or negative value implies no limit.

Returns: an array of parsed Strings, null if null String was input

splitPreserveAllTokens

public static String[] splitPreserveAllTokens(String str)

Splits the provided text into an array, using whitespace as the separator, preserving all tokens, including empty tokens created by adjacent separators. This is an alternative to using StringTokenizer. Whitespace is defined by {@link Character#isWhitespace(char)}.

The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. For more control over the split use the StrTokenizer class.

A null input String returns null.

 StringUtils.splitPreserveAllTokens(null)       = null
 StringUtils.splitPreserveAllTokens("")         = []
 StringUtils.splitPreserveAllTokens("abc def")  = ["abc", "def"]
 StringUtils.splitPreserveAllTokens("abc  def") = ["abc", "", "def"]
 StringUtils.splitPreserveAllTokens(" abc ")    = ["", "abc", ""]
 

Parameters: str the String to parse, may be null

Returns: an array of parsed Strings, null if null String input

Since: 2.1

splitPreserveAllTokens

public static String[] splitPreserveAllTokens(String str, char separatorChar)

Splits the provided text into an array, separator specified, preserving all tokens, including empty tokens created by adjacent separators. This is an alternative to using StringTokenizer.

The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. For more control over the split use the StrTokenizer class.

A null input String returns null.

 StringUtils.splitPreserveAllTokens(null, *)         = null
 StringUtils.splitPreserveAllTokens("", *)           = []
 StringUtils.splitPreserveAllTokens("a.b.c", '.')    = ["a", "b", "c"]
 StringUtils.splitPreserveAllTokens("a..b.c", '.')   = ["a", "b", "c"]
 StringUtils.splitPreserveAllTokens("a:b:c", '.')    = ["a:b:c"]
 StringUtils.splitPreserveAllTokens("a\tb\nc", null) = ["a", "b", "c"]
 StringUtils.splitPreserveAllTokens("a b c", ' ')    = ["a", "b", "c"]
 StringUtils.splitPreserveAllTokens("a b c ", ' ')   = ["a", "b", "c", ""]
 StringUtils.splitPreserveAllTokens("a b c ", ' ')   = ["a", "b", "c", "", ""]
 StringUtils.splitPreserveAllTokens(" a b c", ' ')   = ["", a", "b", "c"]
 StringUtils.splitPreserveAllTokens("  a b c", ' ')  = ["", "", a", "b", "c"]
 StringUtils.splitPreserveAllTokens(" a b c ", ' ')  = ["", a", "b", "c", ""]
 

Parameters: str the String to parse, may be null separatorChar the character used as the delimiter, null splits on whitespace

Returns: an array of parsed Strings, null if null String input

Since: 2.1

splitPreserveAllTokens

public static String[] splitPreserveAllTokens(String str, String separatorChars)

Splits the provided text into an array, separators specified, preserving all tokens, including empty tokens created by adjacent separators. This is an alternative to using StringTokenizer.

The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. For more control over the split use the StrTokenizer class.

A null input String returns null. A null separatorChars splits on whitespace.

 StringUtils.splitPreserveAllTokens(null, *)           = null
 StringUtils.splitPreserveAllTokens("", *)             = []
 StringUtils.splitPreserveAllTokens("abc def", null)   = ["abc", "def"]
 StringUtils.splitPreserveAllTokens("abc def", " ")    = ["abc", "def"]
 StringUtils.splitPreserveAllTokens("abc  def", " ")   = ["abc", "", def"]
 StringUtils.splitPreserveAllTokens("ab:cd:ef", ":")   = ["ab", "cd", "ef"]
 StringUtils.splitPreserveAllTokens("ab:cd:ef:", ":")  = ["ab", "cd", "ef", ""]
 StringUtils.splitPreserveAllTokens("ab:cd:ef::", ":") = ["ab", "cd", "ef", "", ""]
 StringUtils.splitPreserveAllTokens("ab::cd:ef", ":")  = ["ab", "", cd", "ef"]
 StringUtils.splitPreserveAllTokens(":cd:ef", ":")     = ["", cd", "ef"]
 StringUtils.splitPreserveAllTokens("::cd:ef", ":")    = ["", "", cd", "ef"]
 StringUtils.splitPreserveAllTokens(":cd:ef:", ":")    = ["", cd", "ef", ""]
 

Parameters: str the String to parse, may be null separatorChars the characters used as the delimiters, null splits on whitespace

Returns: an array of parsed Strings, null if null String input

Since: 2.1

splitPreserveAllTokens

public static String[] splitPreserveAllTokens(String str, String separatorChars, int max)

Splits the provided text into an array with a maximum length, separators specified, preserving all tokens, including empty tokens created by adjacent separators.

The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. Adjacent separators are treated as one separator.

A null input String returns null. A null separatorChars splits on whitespace.

If more than max delimited substrings are found, the last returned string includes all characters after the first max - 1 returned strings (including separator characters).

 StringUtils.splitPreserveAllTokens(null, *, *)            = null
 StringUtils.splitPreserveAllTokens("", *, *)              = []
 StringUtils.splitPreserveAllTokens("ab de fg", null, 0)   = ["ab", "cd", "ef"]
 StringUtils.splitPreserveAllTokens("ab   de fg", null, 0) = ["ab", "cd", "ef"]
 StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 0)    = ["ab", "cd", "ef"]
 StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 2)    = ["ab", "cd:ef"]
 StringUtils.splitPreserveAllTokens("ab   de fg", null, 2) = ["ab", "  de fg"]
 StringUtils.splitPreserveAllTokens("ab   de fg", null, 3) = ["ab", "", " de fg"]
 StringUtils.splitPreserveAllTokens("ab   de fg", null, 4) = ["ab", "", "", "de fg"]
 

Parameters: str the String to parse, may be null separatorChars the characters used as the delimiters, null splits on whitespace max the maximum number of elements to include in the array. A zero or negative value implies no limit

Returns: an array of parsed Strings, null if null String input

Since: 2.1

strip

public static String strip(String str)

Strips whitespace from the start and end of a String.

This is similar to {@link #trim(String)} but removes whitespace. Whitespace is defined by {@link Character#isWhitespace(char)}.

A null input String returns null.

 StringUtils.strip(null)     = null
 StringUtils.strip("")       = ""
 StringUtils.strip("   ")    = ""
 StringUtils.strip("abc")    = "abc"
 StringUtils.strip("  abc")  = "abc"
 StringUtils.strip("abc  ")  = "abc"
 StringUtils.strip(" abc ")  = "abc"
 StringUtils.strip(" ab c ") = "ab c"
 

Parameters: str the String to remove whitespace from, may be null

Returns: the stripped String, null if null String input

strip

public static String strip(String str, String stripChars)

Strips any of a set of characters from the start and end of a String. This is similar to {@link String#trim()} but allows the characters to be stripped to be controlled.

A null input String returns null. An empty string ("") input returns the empty string.

If the stripChars String is null, whitespace is stripped as defined by {@link Character#isWhitespace(char)}. Alternatively use {@link #strip(String)}.

 StringUtils.strip(null, *)          = null
 StringUtils.strip("", *)            = ""
 StringUtils.strip("abc", null)      = "abc"
 StringUtils.strip("  abc", null)    = "abc"
 StringUtils.strip("abc  ", null)    = "abc"
 StringUtils.strip(" abc ", null)    = "abc"
 StringUtils.strip("  abcyx", "xyz") = "  abc"
 

Parameters: str the String to remove characters from, may be null stripChars the characters to remove, null treated as whitespace

Returns: the stripped String, null if null String input

stripAll

public static String[] stripAll(String[] strs)

Strips whitespace from the start and end of every String in an array. Whitespace is defined by {@link Character#isWhitespace(char)}.

A new array is returned each time, except for length zero. A null array will return null. An empty array will return itself. A null array entry will be ignored.

 StringUtils.stripAll(null)             = null
 StringUtils.stripAll([])               = []
 StringUtils.stripAll(["abc", "  abc"]) = ["abc", "abc"]
 StringUtils.stripAll(["abc  ", null])  = ["abc", null]
 

Parameters: strs the array to remove whitespace from, may be null

Returns: the stripped Strings, null if null array input

stripAll

public static String[] stripAll(String[] strs, String stripChars)

Strips any of a set of characters from the start and end of every String in an array.

Whitespace is defined by {@link Character#isWhitespace(char)}.

A new array is returned each time, except for length zero. A null array will return null. An empty array will return itself. A null array entry will be ignored. A null stripChars will strip whitespace as defined by {@link Character#isWhitespace(char)}.

 StringUtils.stripAll(null, *)                = null
 StringUtils.stripAll([], *)                  = []
 StringUtils.stripAll(["abc", "  abc"], null) = ["abc", "abc"]
 StringUtils.stripAll(["abc  ", null], null)  = ["abc", null]
 StringUtils.stripAll(["abc  ", null], "yz")  = ["abc  ", null]
 StringUtils.stripAll(["yabcz", null], "yz")  = ["abc", null]
 

Parameters: strs the array to remove characters from, may be null stripChars the characters to remove, null treated as whitespace

Returns: the stripped Strings, null if null array input

stripEnd

public static String stripEnd(String str, String stripChars)

Strips any of a set of characters from the end of a String.

A null input String returns null. An empty string ("") input returns the empty string.

If the stripChars String is null, whitespace is stripped as defined by {@link Character#isWhitespace(char)}.

 StringUtils.stripEnd(null, *)          = null
 StringUtils.stripEnd("", *)            = ""
 StringUtils.stripEnd("abc", "")        = "abc"
 StringUtils.stripEnd("abc", null)      = "abc"
 StringUtils.stripEnd("  abc", null)    = "  abc"
 StringUtils.stripEnd("abc  ", null)    = "abc"
 StringUtils.stripEnd(" abc ", null)    = " abc"
 StringUtils.stripEnd("  abcyx", "xyz") = "  abc"
 

Parameters: str the String to remove characters from, may be null stripChars the characters to remove, null treated as whitespace

Returns: the stripped String, null if null String input

stripStart

public static String stripStart(String str, String stripChars)

Strips any of a set of characters from the start of a String.

A null input String returns null. An empty string ("") input returns the empty string.

If the stripChars String is null, whitespace is stripped as defined by {@link Character#isWhitespace(char)}.

 StringUtils.stripStart(null, *)          = null
 StringUtils.stripStart("", *)            = ""
 StringUtils.stripStart("abc", "")        = "abc"
 StringUtils.stripStart("abc", null)      = "abc"
 StringUtils.stripStart("  abc", null)    = "abc"
 StringUtils.stripStart("abc  ", null)    = "abc  "
 StringUtils.stripStart(" abc ", null)    = "abc "
 StringUtils.stripStart("yxabc  ", "xyz") = "abc  "
 

Parameters: str the String to remove characters from, may be null stripChars the characters to remove, null treated as whitespace

Returns: the stripped String, null if null String input

stripToEmpty

public static String stripToEmpty(String str)

Strips whitespace from the start and end of a String returning an empty String if null input.

This is similar to {@link #trimToEmpty(String)} but removes whitespace. Whitespace is defined by {@link Character#isWhitespace(char)}.

 StringUtils.strip(null)     = ""
 StringUtils.strip("")       = ""
 StringUtils.strip("   ")    = ""
 StringUtils.strip("abc")    = "abc"
 StringUtils.strip("  abc")  = "abc"
 StringUtils.strip("abc  ")  = "abc"
 StringUtils.strip(" abc ")  = "abc"
 StringUtils.strip(" ab c ") = "ab c"
 

Parameters: str the String to be stripped, may be null

Returns: the trimmed String, or an empty String if null input

Since: 2.0

stripToNull

public static String stripToNull(String str)

Strips whitespace from the start and end of a String returning null if the String is empty ("") after the strip.

This is similar to {@link #trimToNull(String)} but removes whitespace. Whitespace is defined by {@link Character#isWhitespace(char)}.

 StringUtils.strip(null)     = null
 StringUtils.strip("")       = null
 StringUtils.strip("   ")    = null
 StringUtils.strip("abc")    = "abc"
 StringUtils.strip("  abc")  = "abc"
 StringUtils.strip("abc  ")  = "abc"
 StringUtils.strip(" abc ")  = "abc"
 StringUtils.strip(" ab c ") = "ab c"
 

Parameters: str the String to be stripped, may be null

Returns: the stripped String, null if whitespace, empty or null String input

Since: 2.0

substring

public static String substring(String str, int start)

Gets a substring from the specified String avoiding exceptions.

A negative start position can be used to start n characters from the end of the String.

A null String will return null. An empty ("") String will return "".

 StringUtils.substring(null, *)   = null
 StringUtils.substring("", *)     = ""
 StringUtils.substring("abc", 0)  = "abc"
 StringUtils.substring("abc", 2)  = "c"
 StringUtils.substring("abc", 4)  = ""
 StringUtils.substring("abc", -2) = "bc"
 StringUtils.substring("abc", -4) = "abc"
 

Parameters: str the String to get the substring from, may be null start the position to start from, negative means count back from the end of the String by this many characters

Returns: substring from start position, null if null String input

substring

public static String substring(String str, int start, int end)

Gets a substring from the specified String avoiding exceptions.

A negative start position can be used to start/end n characters from the end of the String.

The returned substring starts with the character in the start position and ends before the end position. All position counting is zero-based -- i.e., to start at the beginning of the string use start = 0. Negative start and end positions can be used to specify offsets relative to the end of the String.

If start is not strictly to the left of end, "" is returned.

 StringUtils.substring(null, *, *)    = null
 StringUtils.substring("", * ,  *)    = "";
 StringUtils.substring("abc", 0, 2)   = "ab"
 StringUtils.substring("abc", 2, 0)   = ""
 StringUtils.substring("abc", 2, 4)   = "c"
 StringUtils.substring("abc", 4, 6)   = ""
 StringUtils.substring("abc", 2, 2)   = ""
 StringUtils.substring("abc", -2, -1) = "b"
 StringUtils.substring("abc", -4, 2)  = "ab"
 

Parameters: str the String to get the substring from, may be null start the position to start from, negative means count back from the end of the String by this many characters end the position to end at (exclusive), negative means count back from the end of the String by this many characters

Returns: substring from start position to end positon, null if null String input

substringAfter

public static String substringAfter(String str, String separator)

Gets the substring after the first occurrence of a separator. The separator is not returned.

A null string input will return null. An empty ("") string input will return the empty string. A null separator will return the empty string if the input string is not null.

 StringUtils.substringAfter(null, *)      = null
 StringUtils.substringAfter("", *)        = ""
 StringUtils.substringAfter(*, null)      = ""
 StringUtils.substringAfter("abc", "a")   = "bc"
 StringUtils.substringAfter("abcba", "b") = "cba"
 StringUtils.substringAfter("abc", "c")   = ""
 StringUtils.substringAfter("abc", "d")   = ""
 StringUtils.substringAfter("abc", "")    = "abc"
 

Parameters: str the String to get a substring from, may be null separator the String to search for, may be null

Returns: the substring after the first occurrence of the separator, null if null String input

Since: 2.0

substringAfterLast

public static String substringAfterLast(String str, String separator)

Gets the substring after the last occurrence of a separator. The separator is not returned.

A null string input will return null. An empty ("") string input will return the empty string. An empty or null separator will return the empty string if the input string is not null.

 StringUtils.substringAfterLast(null, *)      = null
 StringUtils.substringAfterLast("", *)        = ""
 StringUtils.substringAfterLast(*, "")        = ""
 StringUtils.substringAfterLast(*, null)      = ""
 StringUtils.substringAfterLast("abc", "a")   = "bc"
 StringUtils.substringAfterLast("abcba", "b") = "a"
 StringUtils.substringAfterLast("abc", "c")   = ""
 StringUtils.substringAfterLast("a", "a")     = ""
 StringUtils.substringAfterLast("a", "z")     = ""
 

Parameters: str the String to get a substring from, may be null separator the String to search for, may be null

Returns: the substring after the last occurrence of the separator, null if null String input

Since: 2.0

substringBefore

public static String substringBefore(String str, String separator)

Gets the substring before the first occurrence of a separator. The separator is not returned.

A null string input will return null. An empty ("") string input will return the empty string. A null separator will return the input string.

 StringUtils.substringBefore(null, *)      = null
 StringUtils.substringBefore("", *)        = ""
 StringUtils.substringBefore("abc", "a")   = ""
 StringUtils.substringBefore("abcba", "b") = "a"
 StringUtils.substringBefore("abc", "c")   = "ab"
 StringUtils.substringBefore("abc", "d")   = "abc"
 StringUtils.substringBefore("abc", "")    = ""
 StringUtils.substringBefore("abc", null)  = "abc"
 

Parameters: str the String to get a substring from, may be null separator the String to search for, may be null

Returns: the substring before the first occurrence of the separator, null if null String input

Since: 2.0

substringBeforeLast

public static String substringBeforeLast(String str, String separator)

Gets the substring before the last occurrence of a separator. The separator is not returned.

A null string input will return null. An empty ("") string input will return the empty string. An empty or null separator will return the input string.

 StringUtils.substringBeforeLast(null, *)      = null
 StringUtils.substringBeforeLast("", *)        = ""
 StringUtils.substringBeforeLast("abcba", "b") = "abc"
 StringUtils.substringBeforeLast("abc", "c")   = "ab"
 StringUtils.substringBeforeLast("a", "a")     = ""
 StringUtils.substringBeforeLast("a", "z")     = "a"
 StringUtils.substringBeforeLast("a", null)    = "a"
 StringUtils.substringBeforeLast("a", "")      = "a"
 

Parameters: str the String to get a substring from, may be null separator the String to search for, may be null

Returns: the substring before the last occurrence of the separator, null if null String input

Since: 2.0

substringBetween

public static String substringBetween(String str, String tag)

Gets the String that is nested in between two instances of the same String.

A null input String returns null. A null tag returns null.

 StringUtils.substringBetween(null, *)            = null
 StringUtils.substringBetween("", "")             = ""
 StringUtils.substringBetween("", "tag")          = null
 StringUtils.substringBetween("tagabctag", null)  = null
 StringUtils.substringBetween("tagabctag", "")    = ""
 StringUtils.substringBetween("tagabctag", "tag") = "abc"
 

Parameters: str the String containing the substring, may be null tag the String before and after the substring, may be null

Returns: the substring, null if no match

Since: 2.0

substringBetween

public static String substringBetween(String str, String open, String close)

Gets the String that is nested in between two Strings. Only the first match is returned.

A null input String returns null. A null open/close returns null (no match). An empty ("") open/close returns an empty string.

 StringUtils.substringBetween(null, *, *)          = null
 StringUtils.substringBetween("", "", "")          = ""
 StringUtils.substringBetween("", "", "tag")       = null
 StringUtils.substringBetween("", "tag", "tag")    = null
 StringUtils.substringBetween("yabcz", null, null) = null
 StringUtils.substringBetween("yabcz", "", "")     = ""
 StringUtils.substringBetween("yabcz", "y", "z")   = "abc"
 StringUtils.substringBetween("yabczyabcz", "y", "z")   = "abc"
 

Parameters: str the String containing the substring, may be null open the String before the substring, may be null close the String after the substring, may be null

Returns: the substring, null if no match

Since: 2.0

swapCase

public static String swapCase(String str)

Swaps the case of a String changing upper and title case to lower case, and lower case to upper case.

  • Upper case character converts to Lower case
  • Title case character converts to Lower case
  • Lower case character converts to Upper case

For a word based algorithm, see {@link WordUtils#swapCase(String)}. A null input String returns null.

 StringUtils.swapCase(null)                 = null
 StringUtils.swapCase("")                   = ""
 StringUtils.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"
 

NOTE: This method changed in Lang version 2.0. It no longer performs a word based algorithm. If you only use ASCII, you will notice no change. That functionality is available in WordUtils.

Parameters: str the String to swap case, may be null

Returns: the changed String, null if null String input

trim

public static String trim(String str)

Removes control characters (char <= 32) from both ends of this String, handling null by returning null.

The String is trimmed using {@link String#trim()}. Trim removes start and end characters <= 32. To strip whitespace use {@link #strip(String)}.

To trim your choice of characters, use the {@link #strip(String, String)} methods.

 StringUtils.trim(null)          = null
 StringUtils.trim("")            = ""
 StringUtils.trim("     ")       = ""
 StringUtils.trim("abc")         = "abc"
 StringUtils.trim("    abc    ") = "abc"
 

Parameters: str the String to be trimmed, may be null

Returns: the trimmed string, null if null String input

trimToEmpty

public static String trimToEmpty(String str)

Removes control characters (char <= 32) from both ends of this String returning an empty String ("") if the String is empty ("") after the trim or if it is null.

The String is trimmed using {@link String#trim()}. Trim removes start and end characters <= 32. To strip whitespace use {@link #stripToEmpty(String)}.

 StringUtils.trimToEmpty(null)          = ""
 StringUtils.trimToEmpty("")            = ""
 StringUtils.trimToEmpty("     ")       = ""
 StringUtils.trimToEmpty("abc")         = "abc"
 StringUtils.trimToEmpty("    abc    ") = "abc"
 

Parameters: str the String to be trimmed, may be null

Returns: the trimmed String, or an empty String if null input

Since: 2.0

trimToNull

public static String trimToNull(String str)

Removes control characters (char <= 32) from both ends of this String returning null if the String is empty ("") after the trim or if it is null.

The String is trimmed using {@link String#trim()}. Trim removes start and end characters <= 32. To strip whitespace use {@link #stripToNull(String)}.

 StringUtils.trimToNull(null)          = null
 StringUtils.trimToNull("")            = null
 StringUtils.trimToNull("     ")       = null
 StringUtils.trimToNull("abc")         = "abc"
 StringUtils.trimToNull("    abc    ") = "abc"
 

Parameters: str the String to be trimmed, may be null

Returns: the trimmed String, null if only chars <= 32, empty or null String input

Since: 2.0

uncapitalise

public static String uncapitalise(String str)

Deprecated: Use the standardly named {@link #uncapitalize(String)}. Method will be removed in Commons Lang 3.0.

Uncapitalizes a String changing the first letter to title case as per {@link Character#toLowerCase(char)}. No other letters are changed.

Parameters: str the String to uncapitalize, may be null

Returns: the uncapitalized String, null if null String input

uncapitalize

public static String uncapitalize(String str)

Uncapitalizes a String changing the first letter to title case as per {@link Character#toLowerCase(char)}. No other letters are changed.

For a word based algorithm, see {@link WordUtils#uncapitalize(String)}. A null input String returns null.

 StringUtils.uncapitalize(null)  = null
 StringUtils.uncapitalize("")    = ""
 StringUtils.uncapitalize("Cat") = "cat"
 StringUtils.uncapitalize("CAT") = "cAT"
 

Parameters: str the String to uncapitalize, may be null

Returns: the uncapitalized String, null if null String input

Since: 2.0

See Also: uncapitalize capitalize

upperCase

public static String upperCase(String str)

Converts a String to upper case as per {@link String#toUpperCase()}.

A null input String returns null.

 StringUtils.upperCase(null)  = null
 StringUtils.upperCase("")    = ""
 StringUtils.upperCase("aBc") = "ABC"
 

Parameters: str the String to upper case, may be null

Returns: the upper cased String, null if null String input

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