public abstract class StringUtils extends Object
String utility methods.
Mainly for internal use within the framework; consider
Apache's Commons Lang
for a more comprehensive suite of String utilities.
This class delivers some simple functionality that should really be
provided by the core Java String and StringBuilder
classes. It also provides easy-to-use methods to convert between
delimited strings, such as CSV strings, and collections and arrays.
| Constructor and Description |
|---|
StringUtils() |
| 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 Java resource path,
assuming standard Java folder separation (i.e.
|
static String |
arrayToCommaDelimitedString(Object[] arr)
Convert a
String array into a comma delimited String
(i.e., CSV). |
static String |
arrayToDelimitedString(Object[] arr,
String delim)
Convert a
String array into a delimited String (e.g. |
static String |
capitalize(String str)
Capitalize a
String, changing the first letter to
upper case as per Character.toUpperCase(char). |
static String |
cleanPath(String path)
Normalize the path by suppressing sequences like "path/.." and
inner simple dots.
|
static String |
collectionToCommaDelimitedString(Collection<?> coll)
Convert a
Collection into a delimited String (e.g., CSV). |
static String |
collectionToDelimitedString(Collection<?> coll,
String delim)
Convert a
Collection into a delimited String (e.g. |
static String |
collectionToDelimitedString(Collection<?> coll,
String delim,
String prefix,
String suffix)
Convert a
Collection to a delimited String (e.g. |
static Set<String> |
commaDelimitedListToSet(String str)
Convert a comma delimited list (e.g., a row from a CSV file) into a set.
|
static String[] |
commaDelimitedListToStringArray(String str)
Convert a comma delimited list (e.g., a row from a CSV file) 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)
Count the occurrences of the substring
sub 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 that is a delimited list and convert it into a
String array. |
static String[] |
delimitedListToStringArray(String str,
String delimiter,
String charsToDelete)
Take a
String that is a delimited list and convert it into
a String array. |
static boolean |
endsWithIgnoreCase(String str,
String suffix)
Test if the given
String ends with the specified suffix,
ignoring upper/lower case. |
static String |
getFilename(String path)
Extract the filename from the given Java resource path,
e.g.
|
static String |
getFilenameExtension(String path)
Extract the filename extension from the given Java resource 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 contains actual text. |
static boolean |
hasText(String str)
Check whether the given
String contains actual text. |
static boolean |
isEmpty(Object str)
Check whether the given
String is empty. |
static String[] |
mergeStringArrays(String[] array1,
String[] array2)
Merge the given
String arrays into one, with overlapping
array elements only included once. |
static Locale |
parseLocaleString(String localeString)
Parse the given
localeString value into a Locale. |
static TimeZone |
parseTimeZoneString(String timeZoneString)
Parse the given
timeZoneString value into a TimeZone. |
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 of strings and split each element based on the given delimiter.
|
static Properties |
splitArrayElementsIntoProperties(String[] array,
String delimiter,
String charsToDelete)
Take an array of strings and split each element based on the given delimiter.
|
static boolean |
startsWithIgnoreCase(String str,
String prefix)
Test if the given
String starts with the specified prefix,
ignoring upper/lower case. |
static String |
stripFilenameExtension(String path)
Strip the filename extension from the given Java resource path,
e.g.
|
static boolean |
substringMatch(CharSequence str,
int index,
CharSequence substring)
Test whether the given string matches the given substring
at the given index.
|
static String[] |
tokenizeToStringArray(String str,
String delimiters)
|
static String[] |
tokenizeToStringArray(String str,
String delimiters,
boolean trimTokens,
boolean ignoreEmptyTokens)
|
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 in between 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.
|
public static boolean isEmpty(Object str)
String is empty.
This method accepts any Object as an argument, comparing it to
null and the empty String. As a consequence, this method
will never return true for a non-null non-String object.
The Object signature is useful for general attribute handling code that commonly deals with Strings but generally has to iterate over Objects since attributes may e.g. be primitive value objects as well.
str - the candidate Stringpublic static boolean hasLength(CharSequence str)
CharSequence is neither null nor
of length 0.
Note: this method returns true for a CharSequence
that purely consists of whitespace.
StringUtils.hasLength(null) = false
StringUtils.hasLength("") = false
StringUtils.hasLength(" ") = true
StringUtils.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)
String is neither null nor of length 0.
Note: this method returns 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),
hasText(String)public static boolean hasText(CharSequence str)
CharSequence contains actual text.
More specifically, this method returns true if the
CharSequence is not null, its length is greater than
0, and it contains at least one non-whitespace character.
StringUtils.hasText(null) = false
StringUtils.hasText("") = false
StringUtils.hasText(" ") = false
StringUtils.hasText("12345") = true
StringUtils.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)
String contains actual text.
More specifically, this method returns true if the
String is 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)
CharSequence contains any whitespace characters.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)
String contains any whitespace characters.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)
String.str - the String to checkStringCharacter.isWhitespace(char)public static String trimAllWhitespace(String str)
String:
leading, trailing, and in between characters.str - the String to checkStringCharacter.isWhitespace(char)public static String trimLeadingWhitespace(String str)
String.str - the String to checkStringCharacter.isWhitespace(char)public static String trimTrailingWhitespace(String str)
String.str - the String to checkStringCharacter.isWhitespace(char)public static String trimLeadingCharacter(String str, char leadingCharacter)
String.str - the String to checkleadingCharacter - the leading character to be trimmedStringpublic static String trimTrailingCharacter(String str, char trailingCharacter)
String.str - the String to checktrailingCharacter - the trailing character to be trimmedStringpublic static boolean startsWithIgnoreCase(String str, String prefix)
String starts with the specified prefix,
ignoring upper/lower case.str - the String to checkprefix - the prefix to look forString.startsWith(java.lang.String, int)public static boolean endsWithIgnoreCase(String str, String suffix)
String ends with the specified suffix,
ignoring upper/lower case.str - the String to checksuffix - the suffix to look forString.endsWith(java.lang.String)public static boolean substringMatch(CharSequence str, int index, CharSequence substring)
str - the original string (or StringBuilder)index - the index in the original string to start matching againstsubstring - the substring to match at the given indexpublic static int countOccurrencesOf(String str, String sub)
sub in string str.str - string to search insub - string to search forpublic static String replace(String inString, String oldPattern, String newPattern)
inString - String to examineoldPattern - String to replacenewPattern - String to insertString with the replacementspublic static String delete(String inString, String pattern)
inString - the original Stringpattern - the pattern to delete all occurrences ofStringpublic static String deleteAny(String inString, String charsToDelete)
String.inString - the original StringcharsToDelete - a set of characters to delete.
E.g. "az\n" will delete 'a's, 'z's and new lines.Stringpublic static String quote(String str)
String with single quotes.str - the input String (e.g. "myString")String (e.g. "'myString'"),
or null if the input was nullpublic static Object quoteIfString(Object obj)
String with single quotes
if it is a String; keeping the Object as-is else.obj - the input Object (e.g. "myString")String (e.g. "'myString'"),
or the input object as-is if not a Stringpublic static String unqualify(String qualifiedName)
qualifiedName - the qualified namepublic static String unqualify(String qualifiedName, char separator)
qualifiedName - the qualified nameseparator - the separatorpublic 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 capitalizeStringpublic 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 uncapitalizeStringpublic static String getFilename(String path)
"mypath/myfile.txt" -> "myfile.txt".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 pathpublic 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 instance, or null if noneIllegalArgumentException - in case of an invalid locale specificationpublic static String toLanguageTag(Locale locale)
locale - the Locale to transform to a language tagStringpublic static TimeZone parseTimeZoneString(String timeZoneString)
timeZoneString value into a TimeZone.timeZoneString - the time zone String, following TimeZone.getTimeZone(String)
but throwing IllegalArgumentException in case of an invalid time zone specificationTimeZone instanceIllegalArgumentException - in case of an invalid time zone specificationpublic static String[] addStringToArray(String[] array, String str)
String to the given String array,
returning a new array consisting of the input array contents plus
the given String.array - the array to append to (can be null)str - the String to appendnull)public static String[] concatenateStringArrays(String[] array1, String[] array2)
String arrays into one,
with overlapping array elements included twice.
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)
String arrays into one, with overlapping
array elements only included once.
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)
String array into sorted array.array - the source arraynull)public static String[] toStringArray(Collection<String> collection)
Collection into a String array.
The Collection must contain String elements only.
collection - the Collection to copyString arraypublic static String[] toStringArray(Enumeration<String> enumeration)
String array.
The Enumeration must contain String elements only.enumeration - the Enumeration to copyString arraypublic static String[] trimArrayElements(String[] array)
String array,
calling String.trim() on each of them.array - the original String arraypublic static String[] removeDuplicateStrings(String[] array)
As of 4.2, it preserves the original order, as it uses a LinkedHashSet.
array - the String arraypublic static String[] split(String toSplit, String delimiter)
String at the first occurrence of the delimiter.
Does not include the delimiter in the result.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)
String into a String array via a
StringTokenizer.
Trims tokens and omits empty tokens.
The given delimiters string can 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(java.lang.String, java.lang.String).
str - the String to tokenizedelimiters - the delimiter characters, assembled as a String
(each of the characters is individually considered as a delimiter)StringTokenizer,
String.trim(),
delimitedListToStringArray(java.lang.String, java.lang.String)public static String[] tokenizeToStringArray(String str, String delimiters, boolean trimTokens, boolean ignoreEmptyTokens)
String into a String array via a
StringTokenizer.
The given delimiters string can 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(java.lang.String, java.lang.String).
str - the String to tokenizedelimiters - the delimiter characters, assembled as a String
(each of the characters is individually considered as a delimiter)trimTokens - trim the tokens via String.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).StringTokenizer,
String.trim(),
delimitedListToStringArray(java.lang.String, java.lang.String)public static String[] delimitedListToStringArray(String str, String delimiter)
String that is a delimited list and convert it into a
String array.
A single delimiter may consist of more than one character,
but it will still be considered as a single delimiter string, rather
than as bunch of potential delimiter characters, in contrast to
tokenizeToStringArray(java.lang.String, java.lang.String).
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)
String that is a delimited list and convert it into
a String array.
A single delimiter may consist of more than one character,
but it will still be considered as a single delimiter string, rather
than as bunch of potential delimiter characters, in contrast to
tokenizeToStringArray(java.lang.String, java.lang.String).
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 StringtokenizeToStringArray(java.lang.String, java.lang.String)public static String[] commaDelimitedListToStringArray(String str)
str - the input Stringpublic static Set<String> commaDelimitedListToSet(String str)
Note that this will suppress duplicates, and as of 4.2, the elements in
the returned set will preserve the original order in a LinkedHashSet.
str - the input StringString entries in the listremoveDuplicateStrings(String[])public static String collectionToDelimitedString(Collection<?> coll, String delim, String prefix, String suffix)
coll - the Collection to convertdelim - the delimiter to use (typically a ",")prefix - the String to start each element withsuffix - the String to end each element withStringpublic static String collectionToDelimitedString(Collection<?> coll, String delim)
Collection into a delimited String (e.g. CSV).
Useful for toString() implementations.
coll - the Collection to convertdelim - the delimiter to use (typically a ",")Stringpublic static String collectionToCommaDelimitedString(Collection<?> coll)
Collection into a delimited String (e.g., CSV).
Useful for toString() implementations.
coll - the Collection to convertStringpublic static String arrayToDelimitedString(Object[] arr, String delim)
String array into a delimited String (e.g. CSV).
Useful for toString() implementations.
arr - the array to displaydelim - the delimiter to use (typically a ",")String