public final class Strings extends Object
Modifier and Type | Field and Description |
---|---|
static String |
EMPTY
Empty String, equal to
"" . |
static Charset |
UTF_8
Convenience alias for
StandardCharsets.UTF_8 . |
Modifier and Type | Method and Description |
---|---|
static String[] |
addStringToArray(String[] array,
String str)
Append the given String to the given String array, returning a new array
consisting of the input array contents plus the given String.
|
static String |
applyRelativePath(String path,
String relativePath)
Apply the given relative path to the given path,
assuming standard Java folder separation (i.e.
|
static String |
arrayToCommaDelimitedString(Object[] arr)
Convenience method to return a String array as a CSV String.
|
static String |
arrayToDelimitedString(Object[] arr,
String delim)
Convenience method to return a String array as a delimited (e.g.
|
static String |
ascii(byte[] asciiBytes)
Returns
new String(asciiBytes, StandardCharsets.US_ASCII) . |
static byte[] |
ascii(CharSequence s)
Returns the
US_ASCII -encoded bytes of the specified CharSequence . |
static String |
capitalize(String str)
Capitalize a
String , changing the first letter to
upper case as per Character.toUpperCase(char) . |
static CharSequence |
clean(CharSequence str)
Returns the specified
CharSequence without leading or trailing whitespace, or null if there are
no remaining characters. |
static String |
clean(String str)
Returns the specified string without leading or trailing whitespace, or
null if there are no remaining
characters. |
static String |
cleanPath(String path)
Normalize the path by suppressing sequences like "path/.." and
inner simple dots.
|
static String |
collectionToCommaDelimitedString(Collection<?> coll)
Convenience method to return a Collection as a CSV String.
|
static String |
collectionToDelimitedString(Collection<?> coll,
String delim)
Convenience method to return a Collection as a delimited (e.g.
|
static String |
collectionToDelimitedString(Collection<?> coll,
String delim,
String prefix,
String suffix)
Convenience method to return a Collection as a delimited (e.g.
|
static Set<String> |
commaDelimitedListToSet(String str)
Convenience method to convert a CSV string list to a set.
|
static String[] |
commaDelimitedListToStringArray(String str)
Convert a CSV list into an array of Strings.
|
static String[] |
concatenateStringArrays(String[] array1,
String[] array2)
Concatenate the given String arrays into one,
with overlapping array elements included twice.
|
static boolean |
containsWhitespace(CharSequence str)
Check whether the given CharSequence contains any whitespace characters.
|
static boolean |
containsWhitespace(String str)
Check whether the given String contains any whitespace characters.
|
static int |
countOccurrencesOf(String str,
String sub)
Returns the number of occurrences the substring
sub appears in string str . |
static String |
delete(String inString,
String pattern)
Delete all occurrences of the given substring.
|
static String |
deleteAny(String inString,
String charsToDelete)
Delete any character in a given String.
|
static String[] |
delimitedListToStringArray(String str,
String delimiter)
Take a String which is a delimited list and convert it to a String array.
|
static String[] |
delimitedListToStringArray(String str,
String delimiter,
String charsToDelete)
Take a String which is a delimited list and convert it to a String array.
|
static boolean |
endsWithIgnoreCase(String str,
String suffix)
Returns
true if the given string ends with the specified case-insensitive suffix, false otherwise. |
static String |
getFilename(String path)
Extract the filename from the given path,
e.g.
|
static String |
getFilenameExtension(String path)
Extract the filename extension from the given path,
e.g.
|
static boolean |
hasLength(CharSequence str)
Check that the given CharSequence is neither
null nor of length 0. |
static boolean |
hasLength(String str)
Check that the given String is neither
null nor of length 0. |
static boolean |
hasText(CharSequence str)
Check whether the given CharSequence has actual text.
|
static boolean |
hasText(String str)
Check whether the given String has actual text.
|
static String[] |
mergeStringArrays(String[] array1,
String[] array2)
Merge the given String arrays into one, with overlapping
array elements only included once.
|
static StringBuilder |
nespace(StringBuilder sb)
Appends a space character (
' ' ) if the argument is not empty, otherwise does nothing. |
static Locale |
parseLocaleString(String localeString)
Parse the given
localeString value into a Locale . |
static boolean |
pathEquals(String path1,
String path2)
Compare two paths after normalization of them.
|
static String |
quote(String str)
Quote the given String with single quotes.
|
static Object |
quoteIfString(Object obj)
Turn the given Object into a String with single quotes
if it is a String; keeping the Object as-is else.
|
static String[] |
removeDuplicateStrings(String[] array)
Remove duplicate Strings from the given array.
|
static String |
replace(String inString,
String oldPattern,
String newPattern)
Replace all occurrences of a substring within a string with
another string.
|
static String[] |
sortStringArray(String[] array)
Turn given source String array into sorted array.
|
static String[] |
split(String toSplit,
String delimiter)
Split a String at the first occurrence of the delimiter.
|
static Properties |
splitArrayElementsIntoProperties(String[] array,
String delimiter)
Take an array Strings and split each element based on the given delimiter.
|
static Properties |
splitArrayElementsIntoProperties(String[] array,
String delimiter,
String charsToDelete)
Take an array Strings and split each element based on the given delimiter.
|
static boolean |
startsWithIgnoreCase(String str,
String prefix)
Returns
true if the given string starts with the specified case-insensitive prefix, false otherwise. |
static String |
stripFilenameExtension(String path)
Strip the filename extension from the given path,
e.g.
|
static boolean |
substringMatch(CharSequence str,
int index,
CharSequence substring)
Returns
true if the given string matches the given substring at the given index, false otherwise. |
static String |
toBinary(byte b)
Returns a String representation (1s and 0s) of the specified byte.
|
static String |
toBinary(byte[] bytes)
Returns a String representation (1s and 0s) of the specified byte array.
|
static String |
toHex(byte[] bytes)
Returns a hexadecimal String representation of the specified byte array.
|
static String[] |
tokenizeToStringArray(String str,
String delimiters)
Tokenize the given String into a String array via a StringTokenizer.
|
static String[] |
tokenizeToStringArray(String str,
String delimiters,
boolean trimTokens,
boolean ignoreEmptyTokens)
Tokenize the given String into a String array via a StringTokenizer.
|
static String |
toLanguageTag(Locale locale)
Determine the RFC 3066 compliant language tag,
as used for the HTTP "Accept-Language" header.
|
static String[] |
toStringArray(Collection<String> collection)
Copy the given Collection into a String array.
|
static String[] |
toStringArray(Enumeration<String> enumeration)
Copy the given Enumeration into a String array.
|
static String |
trimAllWhitespace(String str)
Trim all whitespace from the given String:
leading, trailing, and intermediate characters.
|
static String[] |
trimArrayElements(String[] array)
Trim the elements of the given String array,
calling
String.trim() on each of them. |
static String |
trimLeadingCharacter(String str,
char leadingCharacter)
Trim all occurrences of the supplied leading character from the given String.
|
static String |
trimLeadingWhitespace(String str)
Trim leading whitespace from the given String.
|
static String |
trimTrailingCharacter(String str,
char trailingCharacter)
Trim all occurrences of the supplied trailing character from the given String.
|
static String |
trimTrailingWhitespace(String str)
Trim trailing whitespace from the given String.
|
static String |
trimWhitespace(String str)
Trim leading and trailing whitespace from the given String.
|
static String |
uncapitalize(String str)
Uncapitalize a
String , changing the first letter to
lower case as per Character.toLowerCase(char) . |
static String |
unqualify(String qualifiedName)
Unqualify a string qualified by a '.' dot character.
|
static String |
unqualify(String qualifiedName,
char separator)
Unqualify a string qualified by a separator character.
|
static String |
utf8(byte[] utf8Bytes)
Returns
new String(utf8Bytes, StandardCharsets.UTF_8) . |
static byte[] |
utf8(CharSequence s)
Returns the specified string's UTF-8 bytes, or
null if the string is null . |
static CharBuffer |
wrap(CharSequence seq)
Returns a
CharBuffer that wraps seq , or an empty buffer if seq is null. |
public static final String EMPTY
""
.public static final Charset UTF_8
StandardCharsets.UTF_8
.public static boolean hasLength(CharSequence str)
null
nor of length 0.
Note: Will return true
for a CharSequence that purely consists of whitespace.
Strings.hasLength(null) = false Strings.hasLength("") = false Strings.hasLength(" ") = true Strings.hasLength("Hello") = true
str
- the CharSequence to check (may be null
)true
if the CharSequence is not null and has lengthhasText(String)
public static boolean hasLength(String str)
null
nor of length 0.
Note: Will return true
for a String that purely consists of whitespace.str
- the String to check (may be null
)true
if the String is not null and has lengthhasLength(CharSequence)
public static boolean hasText(CharSequence str)
true
if the string not null
,
its length is greater than 0, and it contains at least one non-whitespace character.
Strings.hasText(null) = false Strings.hasText("") = false Strings.hasText(" ") = false Strings.hasText("12345") = true Strings.hasText(" 12345 ") = true
str
- the CharSequence to check (may be null
)true
if the CharSequence is not null
,
its length is greater than 0, and it does not contain whitespace onlyCharacter.isWhitespace(char)
public static boolean hasText(String str)
true
if the string not null
,
its length is greater than 0, and it contains at least one non-whitespace character.str
- the String to check (may be null
)true
if the String is not null
, its length is
greater than 0, and it does not contain whitespace onlyhasText(CharSequence)
public static boolean containsWhitespace(CharSequence str)
str
- the CharSequence to check (may be null
)true
if the CharSequence is not empty and
contains at least 1 whitespace characterCharacter.isWhitespace(char)
public static boolean containsWhitespace(String str)
str
- the String to check (may be null
)true
if the String is not empty and
contains at least 1 whitespace charactercontainsWhitespace(CharSequence)
public static String trimWhitespace(String str)
str
- the String to checkCharacter.isWhitespace(char)
public static String clean(String str)
null
if there are no remaining
characters.str
- the string to cleannull
if there are no remaining
characters.public static CharSequence clean(CharSequence str)
CharSequence
without leading or trailing whitespace, or null
if there are
no remaining characters.str
- the CharSequence
to cleannull
if there are no remaining
characters.public static byte[] utf8(CharSequence s)
null
if the string is null
.s
- the string to obtain UTF-8 bytesnull
if the string is null
.public static String utf8(byte[] utf8Bytes)
new String(utf8Bytes, StandardCharsets.UTF_8)
.utf8Bytes
- UTF-8 bytes to use with the String
constructor.new String(utf8Bytes, StandardCharsets.UTF_8)
.public static String ascii(byte[] asciiBytes)
new String(asciiBytes, StandardCharsets.US_ASCII)
.asciiBytes
- US_ASCII bytes to use with the String
constructor.new String(asciiBytes, StandardCharsets.US_ASCII)
.public static byte[] ascii(CharSequence s)
US_ASCII
-encoded bytes of the specified CharSequence
.s
- the CharSequence
to encode to US_ASCII
.US_ASCII
-encoded bytes of the specified CharSequence
.public static CharBuffer wrap(CharSequence seq)
CharBuffer
that wraps seq
, or an empty buffer if seq
is null. If
seq
is already a CharBuffer
, it is returned unmodified.seq
- the CharSequence
to wrap.CharBuffer
that wraps seq
, or an empty buffer if seq
is null.public static String toBinary(byte b)
b
- the byte to represent as 1s and 0s.public static String toBinary(byte[] bytes)
bytes
- the bytes to represent as 1s and 0s.public static String toHex(byte[] bytes)
bytes
- the bytes to represent as a hexidecimal string.public static String trimAllWhitespace(String str)
str
- the String to checkCharacter.isWhitespace(char)
public static String trimLeadingWhitespace(String str)
str
- the String to checkCharacter.isWhitespace(char)
public static String trimTrailingWhitespace(String str)
str
- the String to checkCharacter.isWhitespace(char)
public static String trimLeadingCharacter(String str, char leadingCharacter)
str
- the String to checkleadingCharacter
- the leading character to be trimmedpublic static String trimTrailingCharacter(String str, char trailingCharacter)
str
- the String to checktrailingCharacter
- the trailing character to be trimmedpublic static boolean startsWithIgnoreCase(String str, String prefix)
true
if the given string starts with the specified case-insensitive prefix, false
otherwise.str
- the String to checkprefix
- the prefix to look fortrue
if the given string starts with the specified case-insensitive prefix, false
otherwise.String.startsWith(java.lang.String, int)
public static boolean endsWithIgnoreCase(String str, String suffix)
true
if the given string ends with the specified case-insensitive suffix, false
otherwise.str
- the String to checksuffix
- the suffix to look fortrue
if the given string ends with the specified case-insensitive suffix, false
otherwise.String.endsWith(java.lang.String)
public static boolean substringMatch(CharSequence str, int index, CharSequence substring)
true
if the given string matches the given substring at the given index, false
otherwise.str
- the original string (or StringBuilder)index
- the index in the original string to start matching againstsubstring
- the substring to match at the given indextrue
if the given string matches the given substring at the given index, false
otherwise.public static int countOccurrencesOf(String str, String sub)
sub
appears in string str
.str
- string to search in. Return 0 if this is null.sub
- string to search for. Return 0 if this is null.sub
appears in string str
.public static String replace(String inString, String oldPattern, String newPattern)
inString
- String to examineoldPattern
- String to replacenewPattern
- String to insertpublic static String delete(String inString, String pattern)
inString
- the original Stringpattern
- the pattern to delete all occurrences ofpublic static String deleteAny(String inString, String charsToDelete)
inString
- the original StringcharsToDelete
- a set of characters to delete.
E.g. "az\n" will delete 'a's, 'z's and new lines.public static String quote(String str)
str
- the input String (e.g. "myString")null
if the input was null
public static Object quoteIfString(Object obj)
obj
- the input Object (e.g. "myString")public static String unqualify(String qualifiedName)
qualifiedName
- the qualified namepublic static String unqualify(String qualifiedName, char separator)
qualifiedName
- the qualified nameseparator
- the separatorseparator
character.public static String capitalize(String str)
String
, changing the first letter to
upper case as per Character.toUpperCase(char)
.
No other letters are changed.str
- the String to capitalize, may be null
null
if nullpublic static String uncapitalize(String str)
String
, changing the first letter to
lower case as per Character.toLowerCase(char)
.
No other letters are changed.str
- the String to uncapitalize, may be null
null
if nullpublic static String getFilename(String path)
path
- the file path (may be null
)null
if nonepublic static String getFilenameExtension(String path)
path
- the file path (may be null
)null
if nonepublic static String stripFilenameExtension(String path)
path
- the file path (may be null
)null
if nonepublic static String applyRelativePath(String path, String relativePath)
path
- the path to start from (usually a full file path)relativePath
- the relative path to apply
(relative to the full file path above)public static String cleanPath(String path)
The result is convenient for path comparison. For other uses, notice that Windows separators ("\") are replaced by simple slashes.
path
- the original pathpublic static boolean pathEquals(String path1, String path2)
path1
- first path for comparisonpath2
- second path for comparisonpublic static Locale parseLocaleString(String localeString)
localeString
value into a Locale
.
This is the inverse operation of Locale's toString
.
localeString
- the locale string, following Locale's
toString()
format ("en", "en_UK", etc);
also accepts spaces as separators, as an alternative to underscoresLocale
instancepublic static String toLanguageTag(Locale locale)
locale
- the Locale to transform to a language tagpublic static String[] addStringToArray(String[] array, String str)
array
- the array to append to (can be null
)str
- the String to appendnull
)public static String[] concatenateStringArrays(String[] array1, String[] array2)
The order of elements in the original arrays is preserved.
array1
- the first array (can be null
)array2
- the second array (can be null
)null
if both given arrays were null
)public static String[] mergeStringArrays(String[] array1, String[] array2)
The order of elements in the original arrays is preserved (with the exception of overlapping elements, which are only included on their first occurrence).
array1
- the first array (can be null
)array2
- the second array (can be null
)null
if both given arrays were null
)public static String[] sortStringArray(String[] array)
array
- the source arraynull
)public static String[] toStringArray(Collection<String> collection)
collection
- the Collection to copynull
if the passed-in
Collection was null
)public static String[] toStringArray(Enumeration<String> enumeration)
enumeration
- the Enumeration to copynull
if the passed-in
Enumeration was null
)public static String[] trimArrayElements(String[] array)
String.trim()
on each of them.array
- the original String arraypublic static String[] removeDuplicateStrings(String[] array)
array
- the String arraypublic static String[] split(String toSplit, String delimiter)
toSplit
- the string to splitdelimiter
- to split the string up withnull
if the delimiter wasn't found in the given input Stringpublic static Properties splitArrayElementsIntoProperties(String[] array, String delimiter)
Properties
instance is then generated, with the left of the
delimiter providing the key, and the right of the delimiter providing the value.
Will trim both the key and value before adding them to the
Properties
instance.
array
- the array to processdelimiter
- to split each element using (typically the equals symbol)Properties
instance representing the array contents,
or null
if the array to process was null or emptypublic static Properties splitArrayElementsIntoProperties(String[] array, String delimiter, String charsToDelete)
Properties
instance is then generated, with the left of the
delimiter providing the key, and the right of the delimiter providing the value.
Will trim both the key and value before adding them to the
Properties
instance.
array
- the array to processdelimiter
- to split each element using (typically the equals symbol)charsToDelete
- one or more characters to remove from each element
prior to attempting the split operation (typically the quotation mark
symbol), or null
if no removal should occurProperties
instance representing the array contents,
or null
if the array to process was null
or emptypublic static String[] tokenizeToStringArray(String str, String delimiters)
The given delimiters string is supposed to consist of any number of
delimiter characters. Each of those characters can be used to separate
tokens. A delimiter is always a single character; for multi-character
delimiters, consider using delimitedListToStringArray
str
- the String to tokenizedelimiters
- the delimiter characters, assembled as String
(each of those characters is individually considered as delimiter).StringTokenizer
,
String.trim()
,
delimitedListToStringArray(java.lang.String, java.lang.String)
public static String[] tokenizeToStringArray(String str, String delimiters, boolean trimTokens, boolean ignoreEmptyTokens)
The given delimiters string is supposed to consist of any number of
delimiter characters. Each of those characters can be used to separate
tokens. A delimiter is always a single character; for multi-character
delimiters, consider using delimitedListToStringArray
str
- the String to tokenizedelimiters
- the delimiter characters, assembled as String
(each of those characters is individually considered as delimiter)trimTokens
- trim the tokens via String's trim
ignoreEmptyTokens
- omit empty tokens from the result array
(only applies to tokens that are empty after trimming; StringTokenizer
will not consider subsequent delimiters as token in the first place).null
if the input String
was null
)StringTokenizer
,
String.trim()
,
delimitedListToStringArray(java.lang.String, java.lang.String)
public static String[] delimitedListToStringArray(String str, String delimiter)
A single delimiter can consists of more than one character: It will still
be considered as single delimiter string, rather than as bunch of potential
delimiter characters - in contrast to tokenizeToStringArray
.
str
- the input Stringdelimiter
- the delimiter between elements (this is a single delimiter,
rather than a bunch individual delimiter characters)tokenizeToStringArray(java.lang.String, java.lang.String)
public static String[] delimitedListToStringArray(String str, String delimiter, String charsToDelete)
A single delimiter can consists of more than one character: It will still
be considered as single delimiter string, rather than as bunch of potential
delimiter characters - in contrast to tokenizeToStringArray
.
str
- the input Stringdelimiter
- the delimiter between elements (this is a single delimiter,
rather than a bunch individual delimiter characters)charsToDelete
- a set of characters to delete. Useful for deleting unwanted
line breaks: e.g. "\r\n\f" will delete all new lines and line feeds in a String.tokenizeToStringArray(java.lang.String, java.lang.String)
public static String[] commaDelimitedListToStringArray(String str)
str
- the input Stringpublic static Set<String> commaDelimitedListToSet(String str)
str
- the input Stringpublic static String collectionToDelimitedString(Collection<?> coll, String delim, String prefix, String suffix)
toString()
implementations.coll
- the Collection to displaydelim
- the delimiter to use (probably a ",")prefix
- the String to start each element withsuffix
- the String to end each element withpublic static String collectionToDelimitedString(Collection<?> coll, String delim)
toString()
implementations.coll
- the Collection to displaydelim
- the delimiter to use (probably a ",")public static String collectionToCommaDelimitedString(Collection<?> coll)
toString()
implementations.coll
- the Collection to displaypublic static String arrayToDelimitedString(Object[] arr, String delim)
toString()
implementations.arr
- the array to displaydelim
- the delimiter to use (probably a ",")public static String arrayToCommaDelimitedString(Object[] arr)
toString()
implementations.arr
- the array to displaypublic static StringBuilder nespace(StringBuilder sb)
' '
) if the argument is not empty, otherwise does nothing. This method
can be thought of as "non-empty space". Using this method allows reduction of this:
if (sb.length != 0) { sb.append(' '); } sb.append(nextWord);
To this:
nespace(sb).append(nextWord);
sb
- the string builder to append a space to if non-emptyCopyright © 2014–2025 jsonwebtoken.io. All rights reserved.