StringUtils (Core Language Utilities (Version 2.0))

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org.apache.commons.lang
Class StringUtils

java.lang.Object
  org.apache.commons.lang.StringUtils

public class StringUtils
extends Object

Operations on String that are null safe.

IsEmpty/IsBlank - checks if a String contains text
Trim/Strip - removes leading and trailing whitespace
Equals - compares two strings null-safe
IndexOf/LastIndexOf/Contains - null-safe index-of checks
IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut - index-of any of a set of Strings
ContainsOnly/ContainsNone - does String contains only/none of these characters
Substring/Left/Right/Mid - null-safe substring extractions
SubstringBefore/SubstringAfter/SubstringBetween - substring extraction relative to other strings
Split/Join - splits a String into an array of substrings and vice versa
Replace/Delete/Overlay - Searches a String and replaces one String with another
Chomp/Chop - removes the last part of a String
LeftPad/RightPad/Center/Repeat - pads a String
UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize - changes the case of a String
CountMatches - counts the number of occurrances of one String in another
IsAlpha/IsNumeric/IsWhitespace - checks the characters in a String
DefaultString - protects against a null input String
Reverse/ReverseDelimited - reverses a String
Abbreviate - abbreviates a string using ellipsis
Difference - compares two Strings and reports on their differences
LevensteinDistance - the number of changes needed to change one String into another

The StringUtils class defines certain words related to String handling.

null - null
empty - a zero-length string ("")
space - the space character (' ', char 32)
whitespace - the characters defined by Character.isWhitespace(char)
trim - the characters <= 32 as in String.trim()

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,v 1.107 2003/08/23 10:39:20 scolebourne Exp $
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
See Also:: String

Field Summary
`static String`	`EMPTY` The empty String `""`.

Constructor Summary
`StringUtils()` `StringUtils` instances should NOT be constructed in standard programming.

Method Summary
`static String`	`abbreviate(String str, int maxWidth)` Abbreviates a String using ellipses.
`static String`	`abbreviate(String str, int offset, int maxWidth)` Abbreviates a String using ellipses.
`static String`	`capitalise(String str)` Deprecated. Use the standardly named `capitalize(String)`. Method will be removed in Commons Lang 3.0.
`static String`	`capitaliseAllWords(String str)` Deprecated. Use the relocated `WordUtils.capitalize(String)`. Method will be removed in Commons Lang 3.0.
`static String`	`capitalize(String str)` Capitalizes a String changing the first letter to title case as per `Character.toTitleCase(char)`.
`static String`	`center(String str, int size)` Centers a String in a larger String of size `size` using the space character (' ').
`static String`	`center(String str, int size, char padChar)` Centers a String in a larger String of size `size`.
`static String`	`center(String str, int size, String padStr)` Centers a String in a larger String of size `size`.
`static String`	`chomp(String str)` Removes one newline from end of a String if it's there, otherwise leave it alone.
`static String`	`chomp(String str, String separator)` Removes `separator` from the end of `str` if it's there, otherwise leave it alone.
`static String`	`chompLast(String str)` Deprecated. Use `chomp(String)` instead. Method will be removed in Commons Lang 3.0.
`static String`	`chompLast(String str, String sep)` Deprecated. Use `chomp(String,String)` instead. Method will be removed in Commons Lang 3.0.
`static String`	`chop(String str)` Remove the last character from a String.
`static String`	`chopNewline(String str)` Deprecated. Use `chomp(String)` instead. Method will be removed in Commons Lang 3.0.
`static String`	`clean(String str)` Deprecated. Use the clearer named `trimToEmpty(String)`. Method will be removed in Commons Lang 3.0.
`static String`	`concatenate(Object[] array)` Deprecated. Use the better named `join(Object[])` instead. Method will be removed in Commons Lang 3.0.
`static boolean`	`contains(String str, char searchChar)` Checks if String contains a search character, handling `null`.
`static boolean`	`contains(String str, String searchStr)` Find the first index within a String, handling `null`.
`static boolean`	`containsNone(String str, char[] invalidChars)` Checks that the String does not contain certain characters.
`static boolean`	`containsNone(String str, String invalidChars)` Checks that the String does not contain certain characters.
`static boolean`	`containsOnly(String str, char[] valid)` Checks if the String contains only certain characters.
`static boolean`	`containsOnly(String str, String validChars)` Checks if the String contains only certain characters.
`static int`	`countMatches(String str, String sub)` Counts how many times the substring appears in the larger String.
`static String`	`defaultString(String str)` Returns either the passed in String, or if the String is `null`, an empty String ("").
`static String`	`defaultString(String str, String defaultStr)` Returns either the passed in String, or if the String is `null`, an empty String ("").
`static String`	`deleteSpaces(String str)` Deprecated. Use the better localized `deleteWhitespace(String)`. Method will be removed in Commons Lang 3.0.
`static String`	`deleteWhitespace(String str)` Deletes all whitespaces from a String as defined by `Character.isWhitespace(char)`.
`static String`	`difference(String str1, String str2)` Compares two Strings, and returns the portion where they differ.
`static boolean`	`equals(String str1, String str2)` Compares two Strings, returning `true` if they are equal.
`static boolean`	`equalsIgnoreCase(String str1, String str2)` Compares two Strings, returning `true` if they are equal ignoring the case.
`static String`	`escape(String str)` Deprecated. Use `StringEscapeUtils.escapeJava(String)` This method will be removed in Commons Lang 3.0
`static String`	`getChomp(String str, String sep)` Deprecated. Use `substringAfterLast(String, String)` instead (although this doesn't include the separator) Method will be removed in Commons Lang 3.0.
`static int`	`getLevenshteinDistance(String s, String t)` Find the Levenshtein distance between two Strings.
`static String`	`getNestedString(String str, String tag)` Deprecated. Use the better named `substringBetween(String, String)`. Method will be removed in Commons Lang 3.0.
`static String`	`getNestedString(String str, String open, String close)` Deprecated. Use the better named `substringBetween(String, String, String)`. Method will be removed in Commons Lang 3.0.
`static String`	`getPrechomp(String str, String sep)` Deprecated. Use `substringBefore(String,String)` instead (although this doesn't include the separator). Method will be removed in Commons Lang 3.0.
`static int`	`indexOf(String str, char searchChar)` Finds the first index within a String, handling `null`.
`static int`	`indexOf(String str, char searchChar, int startPos)` Finds the first index within a String from a start position, handling `null`.
`static int`	`indexOf(String str, String searchStr)` Finds the first index within a String, handling `null`.
`static int`	`indexOf(String str, String searchStr, int startPos)` Finds the first index within a String, handling `null`.
`static int`	`indexOfAny(String str, char[] searchChars)` Search a String to find the first index of any character in the given set of characters.
`static int`	`indexOfAny(String str, String searchChars)` Search a String to find the first index of any character in the given set of characters.
`static int`	`indexOfAny(String str, String[] searchStrs)` Find the first index of any of a set of potential substrings.
`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.
`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.
`static int`	`indexOfDifference(String str1, String str2)` Compares two Strings, and returns the index at which the Strings begin to differ.
`static boolean`	`isAlpha(String str)` Checks if the String contains only unicode letters.
`static boolean`	`isAlphanumeric(String str)` Checks if the String contains only unicode letters or digits.
`static boolean`	`isAlphanumericSpace(String str)` Checks if the String contains only unicode letters, digits or space (`' '`).
`static boolean`	`isAlphaSpace(String str)` Checks if the String contains only unicode letters and space (' ').
`static boolean`	`isBlank(String str)` Checks if a String is whitespace, empty ("") or null.
`static boolean`	`isEmpty(String str)` Checks if a String is empty ("") or null.
`static boolean`	`isNotBlank(String str)` Checks if a String is not empty (""), not null and not whitespace only.
`static boolean`	`isNotEmpty(String str)` Checks if a String is not empty ("") and not null.
`static boolean`	`isNumeric(String str)` Checks if the String contains only unicode digits.
`static boolean`	`isNumericSpace(String str)` Checks if the String contains only unicode digits or space (`' '`).
`static boolean`	`isWhitespace(String str)` Checks if the String contains only whitespace.
`static String`	`join(Iterator iterator, char separator)` Joins the elements of the provided `Iterator` into a single String containing the provided elements.
`static String`	`join(Iterator iterator, String separator)` Joins the elements of the provided `Iterator` into a single String containing the provided elements.
`static String`	`join(Object[] array)` Joins the elements of the provided array into a single String containing the provided list of elements.
`static String`	`join(Object[] array, char separator)` Joins the elements of the provided array into a single String containing the provided list of elements.
`static String`	`join(Object[] array, String separator)` Joins the elements of the provided array into a single String containing the provided list of elements.
`static int`	`lastIndexOf(String str, char searchChar)` Finds the last index within a String, handling `null`.
`static int`	`lastIndexOf(String str, char searchChar, int startPos)` Finds the last index within a String from a start position, handling `null`.
`static int`	`lastIndexOf(String str, String searchStr)` Finds the last index within a String, handling `null`.
`static int`	`lastIndexOf(String str, String searchStr, int startPos)` Finds the first index within a String, handling `null`.
`static int`	`lastIndexOfAny(String str, String[] searchStrs)` Find the latest index of any of a set of potential substrings.
`static String`	`left(String str, int len)` Gets the leftmost `len` characters of a String.
`static String`	`leftPad(String str, int size)` Left pad a String with spaces (' ').
`static String`	`leftPad(String str, int size, char padChar)` Left pad a String with a specified character.
`static String`	`leftPad(String str, int size, String padStr)` Left pad a String with a specified String.
`static String`	`lowerCase(String str)` Converts a String to lower case as per `String.toLowerCase()`.
`static String`	`mid(String str, int pos, int len)` Gets `len` characters from the middle of a String.
`static String`	`overlay(String str, String overlay, int start, int end)` Overlays part of a String with another String.
`static String`	`overlayString(String text, String overlay, int start, int end)` Deprecated. Use better named `overlay(String, String, int, int)` instead. Method will be removed in Commons Lang 3.0.
`static String`	`prechomp(String str, String sep)` Deprecated. Use `substringAfter(String,String)` instead. Method will be removed in Commons Lang 3.0.
`static String`	`repeat(String str, int repeat)` Repeat a String `repeat` times to form a new String.
`static String`	`replace(String text, String repl, String with)` Replaces all occurances of a String within another String.
`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.
`static String`	`replaceChars(String str, char searchChar, char replaceChar)` Replaces all occurrances of a character in a String with another.
`static String`	`replaceChars(String str, String searchChars, String replaceChars)` Replaces multiple characters in a String in one go.
`static String`	`replaceOnce(String text, String repl, String with)` Replaces a String with another String inside a larger String, once.
`static String`	`reverse(String str)` Reverses a String as per `StringBuffer.reverse()`.
`static String`	`reverseDelimited(String str, char separatorChar)` Reverses a String that is delimited by a specific character.
`static String`	`reverseDelimitedString(String str, String separatorChars)` Deprecated. Use `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.
`static String`	`right(String str, int len)` Gets the rightmost `len` characters of a String.
`static String`	`rightPad(String str, int size)` Right pad a String with spaces (' ').
`static String`	`rightPad(String str, int size, char padChar)` Right pad a String with a specified character.
`static String`	`rightPad(String str, int size, String padStr)` Right pad a String with a specified String.
`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, separators specified.
`static String`	`strip(String str)` Strips whitespace from the start and end of a String.
`static String`	`strip(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.
`static String`	`stripEnd(String str, String stripChars)` Strips any of a set of characters from the end of a String.
`static String`	`stripStart(String str, String stripChars)` Strips any of a set of characters from the start of a String.
`static String`	`stripToEmpty(String str)` Strips whitespace from the start and end of a String returning an empty String if `null` input.
`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.
`static String`	`substring(String str, int start)` Gets a substring from the specified String avoiding exceptions.
`static String`	`substring(String str, int start, int end)` Gets a substring from the specified String avoiding exceptions.
`static String`	`substringAfter(String str, String separator)` Gets the substring after the first occurance of a separator.
`static String`	`substringAfterLast(String str, String separator)` Gets the substring after the last occurance of a separator.
`static String`	`substringBefore(String str, String separator)` Gets the substring before the first occurance of a separator.
`static String`	`substringBeforeLast(String str, String separator)` Gets the substring before the last occurance of a separator.
`static String`	`substringBetween(String str, String tag)` Gets the String that is nested in between two instances of the same String.
`static String`	`substringBetween(String str, String open, String close)` Gets the String that is nested in between two Strings.
`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.
`static String`	`trim(String str)` Removes control characters (char <= 32) from both ends of this String, handling `null` by returning `null`.
`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`.
`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`.
`static String`	`uncapitalise(String str)` Deprecated. Use the standardly named `uncapitalize(String)`. Method will be removed in Commons Lang 3.0.
`static String`	`uncapitalize(String str)` Uncapitalizes a String changing the first letter to title case as per `Character.toLowerCase(char)`.
`static String`	`upperCase(String str)` Converts a String to upper case as per `String.toUpperCase()`.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EMPTY

public static final String EMPTY

The empty String "".

Since:: 2.0
See Also:: Constant Field Values

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

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

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

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

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

clean

public static String clean(String str)

Deprecated. Use the clearer named 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:: String.trim()

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 String.trim(). Trim removes start and end characters <= 32. To strip whitespace use strip(String).

To trim your choice of characters, use the 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

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 String.trim(). Trim removes start and end characters <= 32. To strip whitespace use 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

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 String.trim(). Trim removes start and end characters <= 32. To strip whitespace use 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

strip

public static String strip(String str)

Strips whitespace from the start and end of a String.

This is similar to trim(String) but removes whitespace. Whitespace is defined by 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

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 trimToNull(String) but removes whitespace. Whitespace is defined by 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

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 trimToEmpty(String) but removes whitespace. Whitespace is defined by 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

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 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 Character.isWhitespace(char). Alternatively use 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

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 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

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 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

stripAll

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

Strips whitespace from the start and end of every String in an array. Whitespace is defined by 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 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 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

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:: 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:: String.equalsIgnoreCase(String)

indexOf

public static int indexOf(String str,
                          char searchChar)

Finds the first index within a String, handling null. This method uses 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

org.apache.commons.lang Class StringUtils

EMPTY

StringUtils

isEmpty

isNotEmpty

isBlank

isNotBlank

clean

trim

trimToNull

trimToEmpty

strip

stripToNull

stripToEmpty

strip

stripStart

stripEnd

stripAll

stripAll

equals

equalsIgnoreCase

indexOf

org.apache.commons.lang
Class StringUtils