- java.lang.Object
-
- org.jooq.tools.StringUtils
-
public final class StringUtils extends Object
Operations on
String
that arenull
safe.- IsEmpty/IsBlank - checks if a String contains text
- Trim/Strip - removes leading and trailing whitespace
- Equals - compares two strings null-safe
- startsWith - check if a String starts with a prefix null-safe
- endsWith - check if a String ends with a suffix null-safe
- IndexOf/LastIndexOf/Contains - null-safe index-of checks
- IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut - index-of any of a set of Strings
- ContainsOnly/ContainsNone/ContainsAny - does String contains only/none/any 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
- Remove/Delete - removes part of a String
- Replace/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 occurrences of one String in another
- IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable - 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 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
handlesnull
input Strings quietly. That is to say that anull
input will returnnull
. Where aboolean
orint
is being returned details vary by method.A side effect of the
null
handling is that aNullPointerException
should be considered a bug inStringUtils
(except for deprecated methods).Methods in this class give sample code to explain their operation. The symbol
*
is used to indicate any input includingnull
.- Since:
- 1.0
- Version:
- $Id: StringUtils.java 911986 2010-02-19 21:19:05Z niallp $
- Author:
- Apache Software Foundation, Apache Jakarta Turbine, Jon S. Stevens, Daniel L. Rall, Greg Coladonato, Ed Korthof, Rand McNeely, Fredrik Westermarck, Holger Krauth, Alexander Day Chaffee, Henning P. Schmiedehausen, Arun Mammen Thomas, Gary Gregory, Phil Steitz, Al Chou, Michael Davey, Reuben Sivan, Chris Hyzer, Scott Johnson
- See Also:
String
-
-
Field Summary
Fields Modifier and Type Field Description static String
EMPTY
The empty String""
.static int
INDEX_NOT_FOUND
Represents a failed index search.
-
Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description 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 boolean
containsAny(String str, char... searchChars)
Checks if the String contains any character in the given set of characters.static int
countMatches(String str, String sub)
Counts how many times the substring appears in the larger String.static String
defaultIfBlank(String str, String defaultStr)
Returns either the passed in CharSequence, or if the CharSequence is whitespace, empty ("") ornull
, the value ofdefaultStr
.static String
defaultIfEmpty(String str, String defaultStr)
Returns either the passed in String, or if the String is empty ornull
, the value ofdefaultStr
.static <T> T
defaultIfNull(T object, T defaultValue)
Returns a default value if the object passed isnull
.static String
defaultString(String str)
Returns either the passed in String, or if the String isnull
, an empty String ("").static String
defaultString(String str, String defaultStr)
Returns either the passed in String, or if the String isnull
, the value ofdefaultStr
.static boolean
equals(Object o1, Object o2)
Compares two objects for deep equality, where either one or both objects may benull
.static boolean
equals(String o1, String o2)
Compares two strings for equality, where either one or both objects may benull
.static <T> T
firstNonNull(T... objects)
Returns the first non-null
argument.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 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, char separator, int startIndex, int endIndex)
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 String
join(Object[] array, String separator, int startIndex, int endIndex)
Joins the elements of the provided array into a single String containing the provided list of elements.static <T> String
join(T... elements)
Joins the elements of the provided array into a single String containing the provided list of elements.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
replace(String text, String searchString, String replacement)
Replaces all occurrences of a String within another String.static String
replace(String text, String searchString, String replacement, int max)
Replaces a String with another String inside a larger String, for the firstmax
values of the search String.static String
replaceEach(String text, String[] searchList, String[] replacementList)
Replaces all occurrences of Strings within another 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 regex, CharSequence input)
A custom adaptation ofPattern.split(CharSequence, int)
.static String
toCamelCase(String string)
Convert a string to camel casestatic String
toCamelCaseLC(String string)
Convert a string to camel case starting with a lower case letterstatic String
toLC(String string)
Change a string's first letter to lower casestatic String
toUC(String string)
Change a string's first letter to upper case
-
-
-
Field Detail
-
EMPTY
public static final String EMPTY
The empty String""
.- Since:
- 2.0
- See Also:
- Constant Field Values
-
INDEX_NOT_FOUND
public static final int INDEX_NOT_FOUND
Represents a failed index search.- Since:
- 2.1
- See Also:
- Constant Field Values
-
-
Method Detail
-
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:
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 ofdefaultStr
.StringUtils.defaultString(null, "NULL") = "NULL" StringUtils.defaultString("", "NULL") = "" StringUtils.defaultString("bat", "NULL") = "bat"
- Parameters:
str
- the String to check, may be nulldefaultStr
- the default String to return if the input isnull
, may be null- Returns:
- the passed in String, or the default if it was
null
- See Also:
String.valueOf(Object)
-
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 ofdefaultStr
.StringUtils.defaultIfEmpty(null, "NULL") = "NULL" StringUtils.defaultIfEmpty("", "NULL") = "NULL" StringUtils.defaultIfEmpty("bat", "NULL") = "bat"
- Parameters:
str
- the String to check, may be nulldefaultStr
- the default String to return if the input is empty ("") ornull
, may be null- Returns:
- the passed in String, or the default
- See Also:
defaultString(String, String)
-
defaultIfBlank
public static String defaultIfBlank(String str, String defaultStr)
Returns either the passed in CharSequence, or if the CharSequence is whitespace, empty ("") or
null
, the value ofdefaultStr
.StringUtils.defaultIfBlank(null, "NULL") = "NULL" StringUtils.defaultIfBlank("", "NULL") = "NULL" StringUtils.defaultIfBlank(" ", "NULL") = "NULL" StringUtils.defaultIfBlank("bat", "NULL") = "bat" StringUtils.defaultIfBlank("", null) = null
- Parameters:
str
- the CharSequence to check, may be nulldefaultStr
- the default CharSequence to return if the input is whitespace, empty ("") ornull
, may be null- Returns:
- the passed in CharSequence, or the default
- See Also:
defaultString(String, String)
-
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
-
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
-
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 returns0
.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 nullsub
- the substring to count, may be null- Returns:
- the number of occurrences, 0 if either String is
null
-
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 nullsize
- 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 nullsize
- the size to pad topadChar
- 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 nullsize
- the size to pad topadStr
- 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
-
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 nullsize
- 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 nullsize
- the size to pad topadChar
- 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 nullsize
- the size to pad topadStr
- 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
-
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:
- If
str
is less thanmaxWidth
characters long, return it. - Else abbreviate it to
(substring(str, 0, max-3) + "...")
. - If
maxWidth
is less than4
, throw anIllegalArgumentException
. - In no case will it return a String of length greater than
maxWidth
.
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 nullmaxWidth
- 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
- If
-
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 nulloffset
- left edge of source StringmaxWidth
- 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
-
containsAny
public static boolean containsAny(String str, char... searchChars)
Checks if the String contains any character in the given set of characters.
A
null
String will returnfalse
. Anull
or zero length search array will returnfalse
.StringUtils.containsAny(null, *) = false StringUtils.containsAny("", *) = false StringUtils.containsAny(*, null) = false StringUtils.containsAny(*, []) = false StringUtils.containsAny("zzabyycdxx",['z','a']) = true StringUtils.containsAny("zzabyycdxx",['b','y']) = true StringUtils.containsAny("aba", ['z']) = false
- Parameters:
str
- the String to check, may be nullsearchChars
- the chars to search for, may be null- Returns:
- the
true
if any of the chars are found,false
if no match or null input - Since:
- 2.4
-
replace
public static String replace(String text, String searchString, String replacement)
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 nullsearchString
- the String to search for, may be nullreplacement
- the String to replace it with, may be null- Returns:
- the text with any replacements processed,
null
if null String input - See Also:
replace(String text, String searchString, String replacement, int max)
-
replace
public static String replace(String text, String searchString, String replacement, 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 nullsearchString
- the String to search for, may be nullreplacement
- the String to replace it with, may be nullmax
- maximum number of values to replace, or-1
if no maximum- Returns:
- the text with any replacements processed,
null
if null String input
-
replaceEach
public static String replaceEach(String text, String[] searchList, String[] replacementList)
Replaces all occurrences of Strings within another String.
A
null
reference passed to this method is a no-op, or if any "search string" or "string to replace" is null, that replace will be ignored. This will not repeat. For repeating replaces, call the overloaded method.StringUtils.replaceEach(null, *, *) = null StringUtils.replaceEach("", *, *) = "" StringUtils.replaceEach("aba", null, null) = "aba" StringUtils.replaceEach("aba", new String[0], null) = "aba" StringUtils.replaceEach("aba", null, new String[0]) = "aba" StringUtils.replaceEach("aba", new String[]{"a"}, null) = "aba" StringUtils.replaceEach("aba", new String[]{"a"}, new String[]{""}) = "b" StringUtils.replaceEach("aba", new String[]{null}, new String[]{"a"}) = "aba" StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"}) = "wcte" (example of how it does not repeat) StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}) = "dcte"
- Parameters:
text
- text to search and replace in, no-op if nullsearchList
- the Strings to search for, no-op if nullreplacementList
- the Strings to replace them with, no-op if null- Returns:
- the text with any replacements processed,
null
if null String input - Throws:
IndexOutOfBoundsException
- if the lengths of the arrays are not the same (null is ok, and/or size 0)- Since:
- 2.4
-
join
@SafeVarargs public static <T> String join(T... elements)
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"
- Type Parameters:
T
- the specific type of values to join together- Parameters:
elements
- the values to join together, may be null- Returns:
- the joined String,
null
if null array input - Since:
- 2.0, 3.0 Changed signature to use varargs
-
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 nullseparator
- the separator character to use- Returns:
- the joined String,
null
if null array input - Since:
- 2.0
-
join
public static String join(Object[] array, char separator, int startIndex, int endIndex)
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 nullseparator
- the separator character to usestartIndex
- the first index to start joining from. It is an error to pass in an end index past the end of the arrayendIndex
- the index to stop joining from (exclusive). It is an error to pass in an end index past the end of the array- 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 nullseparator
- the separator character to use, null treated as ""- Returns:
- the joined String,
null
if null array input
-
join
public static String join(Object[] array, String separator, int startIndex, int endIndex)
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 nullseparator
- the separator character to use, null treated as ""startIndex
- the first index to start joining from. It is an error to pass in an end index past the end of the arrayendIndex
- the index to stop joining from (exclusive). It is an error to pass in an end index past the end of the array- Returns:
- the joined String,
null
if null array input
-
equals
public static boolean equals(String o1, String o2)
Compares two strings for equality, where either one or both objects may be
null
.ObjectUtils.equals(null, null) = true ObjectUtils.equals(null, "") = false ObjectUtils.equals("", null) = false ObjectUtils.equals("", "") = true
- Parameters:
o1
- the first object, may benull
o2
- the second object, may benull
- Returns:
true
if the values of both objects are the same
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equals
public static boolean equals(Object o1, Object o2)
Compares two objects for deep equality, where either one or both objects may be
null
.ObjectUtils.equals(null, null) = true ObjectUtils.equals(null, "") = false ObjectUtils.equals("", null) = false ObjectUtils.equals("", "") = true ObjectUtils.equals(Boolean.TRUE, null) = false ObjectUtils.equals(Boolean.TRUE, "true") = false ObjectUtils.equals(Boolean.TRUE, Boolean.TRUE) = true ObjectUtils.equals(Boolean.TRUE, Boolean.FALSE) = false
- Parameters:
o1
- the first object, may benull
o2
- the second object, may benull
- Returns:
true
if the values of both objects are the same
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defaultIfNull
public static <T> T defaultIfNull(T object, T defaultValue)
Returns a default value if the object passed is
null
.ObjectUtils.defaultIfNull(null, null) = null ObjectUtils.defaultIfNull(null, "") = "" ObjectUtils.defaultIfNull(null, "zz") = "zz" ObjectUtils.defaultIfNull("abc", *) = "abc" ObjectUtils.defaultIfNull(Boolean.TRUE, *) = Boolean.TRUE
- Type Parameters:
T
- the type of the object- Parameters:
object
- theObject
to test, may benull
defaultValue
- the default value to return, may benull
- Returns:
object
if it is notnull
, defaultValue otherwise
-
firstNonNull
@SafeVarargs public static <T> T firstNonNull(T... objects)
Returns the first non-
null
argument.- Type Parameters:
T
- the type of the objects- Parameters:
objects
- the elements to test, may not benull
but empty- Returns:
- first non-
null
element inobjects
, otherwisenull
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toCamelCaseLC
public static String toCamelCaseLC(String string)
Convert a string to camel case starting with a lower case letter
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split
public static String[] split(String regex, CharSequence input)
A custom adaptation ofPattern.split(CharSequence, int)
.This is useful if the matched split-tokens should be returned as well. For example:
split("e", "hello world") // ["h", "e", "llo world"] split("o", "hello world") // ["hell", "o", " w", "o", "rld"] split("[eo]", "hello world") // ["h", "e", "ll", "o", " w", "o", "rld"]
The result will always be an odd-length array.
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