Class CharUtils
- java.lang.Object
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- org.apache.commons.lang3.CharUtils
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public class CharUtils extends java.lang.Object
Operations on char primitives and Character objects.
This class tries to handle
null
input gracefully. An exception will not be thrown for anull
input. Each method documents its behavior in more detail.#ThreadSafe#
- Since:
- 2.1
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Constructor Summary
Constructors Constructor Description CharUtils()
CharUtils
instances should NOT be constructed in standard programming.
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Method Summary
All Methods Static Methods Concrete Methods Deprecated Methods Modifier and Type Method Description static int
compare(char x, char y)
Compares twochar
values numerically.static boolean
isAscii(char ch)
Checks whether the character is ASCII 7 bit.static boolean
isAsciiAlpha(char ch)
Checks whether the character is ASCII 7 bit alphabetic.static boolean
isAsciiAlphaLower(char ch)
Checks whether the character is ASCII 7 bit alphabetic lower case.static boolean
isAsciiAlphanumeric(char ch)
Checks whether the character is ASCII 7 bit numeric.static boolean
isAsciiAlphaUpper(char ch)
Checks whether the character is ASCII 7 bit alphabetic upper case.static boolean
isAsciiControl(char ch)
Checks whether the character is ASCII 7 bit control.static boolean
isAsciiNumeric(char ch)
Checks whether the character is ASCII 7 bit numeric.static boolean
isAsciiPrintable(char ch)
Checks whether the character is ASCII 7 bit printable.static char
toChar(java.lang.Character ch)
Converts the Character to a char throwing an exception fornull
.static char
toChar(java.lang.Character ch, char defaultValue)
Converts the Character to a char handlingnull
.static char
toChar(java.lang.String str)
Converts the String to a char using the first character, throwing an exception on empty Strings.static char
toChar(java.lang.String str, char defaultValue)
Converts the String to a char using the first character, defaulting the value on empty Strings.static java.lang.Character
toCharacterObject(char ch)
Deprecated.Java 5 introducedCharacter.valueOf(char)
which caches chars 0 through 127.static java.lang.Character
toCharacterObject(java.lang.String str)
Converts the String to a Character using the first character, returning null for empty Strings.static int
toIntValue(char ch)
Converts the character to the Integer it represents, throwing an exception if the character is not numeric.static int
toIntValue(char ch, int defaultValue)
Converts the character to the Integer it represents, throwing an exception if the character is not numeric.static int
toIntValue(java.lang.Character ch)
Converts the character to the Integer it represents, throwing an exception if the character is not numeric.static int
toIntValue(java.lang.Character ch, int defaultValue)
Converts the character to the Integer it represents, throwing an exception if the character is not numeric.static java.lang.String
toString(char ch)
Converts the character to a String that contains the one character.static java.lang.String
toString(java.lang.Character ch)
Converts the character to a String that contains the one character.static java.lang.String
unicodeEscaped(char ch)
Converts the string to the Unicode format ' '.static java.lang.String
unicodeEscaped(java.lang.Character ch)
Converts the string to the Unicode format ' '.
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Field Detail
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LF
public static final char LF
Linefeed character LF ('\n'
, Unicode 000a).- Since:
- 2.2
- See Also:
- JLF: Escape Sequences for Character and String Literals, Constant Field Values
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CR
public static final char CR
Carriage return characterf CR ('\r', Unicode 000d).- Since:
- 2.2
- See Also:
- JLF: Escape Sequences for Character and String Literals, Constant Field Values
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NUL
public static final char NUL
null control character ('\0'), abbreviated NUL.
- Since:
- 3.6
- See Also:
- Constant Field Values
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Method Detail
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toCharacterObject
@Deprecated public static java.lang.Character toCharacterObject(char ch)
Deprecated.Java 5 introducedCharacter.valueOf(char)
which caches chars 0 through 127.Converts the character to a Character.
For ASCII 7 bit characters, this uses a cache that will return the same Character object each time.
CharUtils.toCharacterObject(' ') = ' ' CharUtils.toCharacterObject('A') = 'A'
- Parameters:
ch
- the character to convert- Returns:
- a Character of the specified character
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toCharacterObject
public static java.lang.Character toCharacterObject(java.lang.String str)
Converts the String to a Character using the first character, returning null for empty Strings.
For ASCII 7 bit characters, this uses a cache that will return the same Character object each time.
CharUtils.toCharacterObject(null) = null CharUtils.toCharacterObject("") = null CharUtils.toCharacterObject("A") = 'A' CharUtils.toCharacterObject("BA") = 'B'
- Parameters:
str
- the character to convert- Returns:
- the Character value of the first letter of the String
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toChar
public static char toChar(java.lang.Character ch)
Converts the Character to a char throwing an exception for
null
.CharUtils.toChar(' ') = ' ' CharUtils.toChar('A') = 'A' CharUtils.toChar(null) throws IllegalArgumentException
- Parameters:
ch
- the character to convert- Returns:
- the char value of the Character
- Throws:
java.lang.NullPointerException
- if the Character is null
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toChar
public static char toChar(java.lang.Character ch, char defaultValue)
Converts the Character to a char handling
null
.CharUtils.toChar(null, 'X') = 'X' CharUtils.toChar(' ', 'X') = ' ' CharUtils.toChar('A', 'X') = 'A'
- Parameters:
ch
- the character to convertdefaultValue
- the value to use if the Character is null- Returns:
- the char value of the Character or the default if null
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toChar
public static char toChar(java.lang.String str)
Converts the String to a char using the first character, throwing an exception on empty Strings.
CharUtils.toChar("A") = 'A' CharUtils.toChar("BA") = 'B' CharUtils.toChar(null) throws IllegalArgumentException CharUtils.toChar("") throws IllegalArgumentException
- Parameters:
str
- the character to convert- Returns:
- the char value of the first letter of the String
- Throws:
java.lang.NullPointerException
- if the string is nulljava.lang.IllegalArgumentException
- if the String is empty
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toChar
public static char toChar(java.lang.String str, char defaultValue)
Converts the String to a char using the first character, defaulting the value on empty Strings.
CharUtils.toChar(null, 'X') = 'X' CharUtils.toChar("", 'X') = 'X' CharUtils.toChar("A", 'X') = 'A' CharUtils.toChar("BA", 'X') = 'B'
- Parameters:
str
- the character to convertdefaultValue
- the value to use if the Character is null- Returns:
- the char value of the first letter of the String or the default if null
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toIntValue
public static int toIntValue(char ch)
Converts the character to the Integer it represents, throwing an exception if the character is not numeric.
This method converts the char '1' to the int 1 and so on.
CharUtils.toIntValue('3') = 3 CharUtils.toIntValue('A') throws IllegalArgumentException
- Parameters:
ch
- the character to convert- Returns:
- the int value of the character
- Throws:
java.lang.IllegalArgumentException
- if the character is not ASCII numeric
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toIntValue
public static int toIntValue(char ch, int defaultValue)
Converts the character to the Integer it represents, throwing an exception if the character is not numeric.
This method converts the char '1' to the int 1 and so on.
CharUtils.toIntValue('3', -1) = 3 CharUtils.toIntValue('A', -1) = -1
- Parameters:
ch
- the character to convertdefaultValue
- the default value to use if the character is not numeric- Returns:
- the int value of the character
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toIntValue
public static int toIntValue(java.lang.Character ch)
Converts the character to the Integer it represents, throwing an exception if the character is not numeric.
This method converts the char '1' to the int 1 and so on.
CharUtils.toIntValue('3') = 3 CharUtils.toIntValue(null) throws IllegalArgumentException CharUtils.toIntValue('A') throws IllegalArgumentException
- Parameters:
ch
- the character to convert, not null- Returns:
- the int value of the character
- Throws:
java.lang.NullPointerException
- if the Character is nulljava.lang.IllegalArgumentException
- if the Character is not ASCII numeric
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toIntValue
public static int toIntValue(java.lang.Character ch, int defaultValue)
Converts the character to the Integer it represents, throwing an exception if the character is not numeric.
This method converts the char '1' to the int 1 and so on.
CharUtils.toIntValue(null, -1) = -1 CharUtils.toIntValue('3', -1) = 3 CharUtils.toIntValue('A', -1) = -1
- Parameters:
ch
- the character to convertdefaultValue
- the default value to use if the character is not numeric- Returns:
- the int value of the character
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toString
public static java.lang.String toString(char ch)
Converts the character to a String that contains the one character.
For ASCII 7 bit characters, this uses a cache that will return the same String object each time.
CharUtils.toString(' ') = " " CharUtils.toString('A') = "A"
- Parameters:
ch
- the character to convert- Returns:
- a String containing the one specified character
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toString
public static java.lang.String toString(java.lang.Character ch)
Converts the character to a String that contains the one character.
For ASCII 7 bit characters, this uses a cache that will return the same String object each time.
If
null
is passed in,null
will be returned.CharUtils.toString(null) = null CharUtils.toString(' ') = " " CharUtils.toString('A') = "A"
- Parameters:
ch
- the character to convert- Returns:
- a String containing the one specified character
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unicodeEscaped
public static java.lang.String unicodeEscaped(char ch)
Converts the string to the Unicode format ' '.
This format is the Java source code format.
CharUtils.unicodeEscaped(' ') = " " CharUtils.unicodeEscaped('A') = "A"
- Parameters:
ch
- the character to convert- Returns:
- the escaped Unicode string
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unicodeEscaped
public static java.lang.String unicodeEscaped(java.lang.Character ch)
Converts the string to the Unicode format ' '.
This format is the Java source code format.
If
null
is passed in,null
will be returned.CharUtils.unicodeEscaped(null) = null CharUtils.unicodeEscaped(' ') = " " CharUtils.unicodeEscaped('A') = "A"
- Parameters:
ch
- the character to convert, may be null- Returns:
- the escaped Unicode string, null if null input
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isAscii
public static boolean isAscii(char ch)
Checks whether the character is ASCII 7 bit.
CharUtils.isAscii('a') = true CharUtils.isAscii('A') = true CharUtils.isAscii('3') = true CharUtils.isAscii('-') = true CharUtils.isAscii('\n') = true CharUtils.isAscii('©') = false
- Parameters:
ch
- the character to check- Returns:
- true if less than 128
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isAsciiPrintable
public static boolean isAsciiPrintable(char ch)
Checks whether the character is ASCII 7 bit printable.
CharUtils.isAsciiPrintable('a') = true CharUtils.isAsciiPrintable('A') = true CharUtils.isAsciiPrintable('3') = true CharUtils.isAsciiPrintable('-') = true CharUtils.isAsciiPrintable('\n') = false CharUtils.isAsciiPrintable('©') = false
- Parameters:
ch
- the character to check- Returns:
- true if between 32 and 126 inclusive
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isAsciiControl
public static boolean isAsciiControl(char ch)
Checks whether the character is ASCII 7 bit control.
CharUtils.isAsciiControl('a') = false CharUtils.isAsciiControl('A') = false CharUtils.isAsciiControl('3') = false CharUtils.isAsciiControl('-') = false CharUtils.isAsciiControl('\n') = true CharUtils.isAsciiControl('©') = false
- Parameters:
ch
- the character to check- Returns:
- true if less than 32 or equals 127
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isAsciiAlpha
public static boolean isAsciiAlpha(char ch)
Checks whether the character is ASCII 7 bit alphabetic.
CharUtils.isAsciiAlpha('a') = true CharUtils.isAsciiAlpha('A') = true CharUtils.isAsciiAlpha('3') = false CharUtils.isAsciiAlpha('-') = false CharUtils.isAsciiAlpha('\n') = false CharUtils.isAsciiAlpha('©') = false
- Parameters:
ch
- the character to check- Returns:
- true if between 65 and 90 or 97 and 122 inclusive
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isAsciiAlphaUpper
public static boolean isAsciiAlphaUpper(char ch)
Checks whether the character is ASCII 7 bit alphabetic upper case.
CharUtils.isAsciiAlphaUpper('a') = false CharUtils.isAsciiAlphaUpper('A') = true CharUtils.isAsciiAlphaUpper('3') = false CharUtils.isAsciiAlphaUpper('-') = false CharUtils.isAsciiAlphaUpper('\n') = false CharUtils.isAsciiAlphaUpper('©') = false
- Parameters:
ch
- the character to check- Returns:
- true if between 65 and 90 inclusive
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isAsciiAlphaLower
public static boolean isAsciiAlphaLower(char ch)
Checks whether the character is ASCII 7 bit alphabetic lower case.
CharUtils.isAsciiAlphaLower('a') = true CharUtils.isAsciiAlphaLower('A') = false CharUtils.isAsciiAlphaLower('3') = false CharUtils.isAsciiAlphaLower('-') = false CharUtils.isAsciiAlphaLower('\n') = false CharUtils.isAsciiAlphaLower('©') = false
- Parameters:
ch
- the character to check- Returns:
- true if between 97 and 122 inclusive
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isAsciiNumeric
public static boolean isAsciiNumeric(char ch)
Checks whether the character is ASCII 7 bit numeric.
CharUtils.isAsciiNumeric('a') = false CharUtils.isAsciiNumeric('A') = false CharUtils.isAsciiNumeric('3') = true CharUtils.isAsciiNumeric('-') = false CharUtils.isAsciiNumeric('\n') = false CharUtils.isAsciiNumeric('©') = false
- Parameters:
ch
- the character to check- Returns:
- true if between 48 and 57 inclusive
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isAsciiAlphanumeric
public static boolean isAsciiAlphanumeric(char ch)
Checks whether the character is ASCII 7 bit numeric.
CharUtils.isAsciiAlphanumeric('a') = true CharUtils.isAsciiAlphanumeric('A') = true CharUtils.isAsciiAlphanumeric('3') = true CharUtils.isAsciiAlphanumeric('-') = false CharUtils.isAsciiAlphanumeric('\n') = false CharUtils.isAsciiAlphanumeric('©') = false
- Parameters:
ch
- the character to check- Returns:
- true if between 48 and 57 or 65 and 90 or 97 and 122 inclusive
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compare
public static int compare(char x, char y)
Compares two
char
values numerically. This is the same functionality as provided in Java 7.- Parameters:
x
- the firstchar
to comparey
- the secondchar
to compare- Returns:
- the value
0
ifx == y
; a value less than0
ifx < y
; and a value greater than0
ifx > y
- Since:
- 3.4
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