public final class HexFormat extends Object
HexFormat
converts between bytes and chars and hex-encoded strings which may include additional formatting markup such as prefixes, suffixes, and delimiters. There are two factories of HexFormat
with preset parameters of()
and ofDelimiter(delimiter)
. For other parameter combinations the withXXX
methods return copies of HexFormat
modified withPrefix(String)
, withSuffix(String)
, withDelimiter(String)
or choice of withUpperCase()
or withLowerCase()
parameters.
For primitive to hexadecimal string conversions the toHexDigits
methods include toHexDigits(byte)
, toHexDigits(int)
, and toHexDigits(long)
, etc. The default is to use lowercase characters "0-9","a-f"
. For conversions producing uppercase hexadecimal the characters are "0-9","A-F"
. Only the HexFormat.isUpperCase()
parameter is considered; the delimiter, prefix and suffix are not used.
For hexadecimal string to primitive conversions the fromHexDigits
methods include fromHexDigits(string)
, fromHexDigitsToLong(string)
, and fromHexDigit(int)
converts a single character or codepoint. For conversions from hexadecimal characters the digits and uppercase and lowercase characters in "0-9", "a-f", and "A-F"
are converted to corresponding values 0-15
. The delimiter, prefix, suffix, and uppercase parameters are not used.
For byte array to formatted hexadecimal string conversions the formatHex
methods include formatHex(byte[])
and formatHex(Appendable, byte[])
. The formatted output is a string or is appended to an Appendable
such as StringBuilder
or PrintStream
. Each byte value is formatted as the prefix, two hexadecimal characters from the uppercase or lowercase digits, and the suffix. A delimiter follows each formatted value, except the last. For conversions producing uppercase hexadecimal strings use withUpperCase()
.
For formatted hexadecimal string to byte array conversions the parseHex
methods include parseHex(CharSequence)
and parseHex(char[], offset, length)
. Each byte value is parsed from the prefix, two case insensitive hexadecimal characters, and the suffix. A delimiter follows each formatted value, except the last.
toHexDigits(int)
and converted from a string to a primitive value using fromHexDigits(string)
.
HexFormat hex = HexFormat.of();
byte b = 127;
String byteStr = hex.toHexDigits(b);
byte byteVal = (byte)hex.fromHexDigits(byteStr);
assert(byteStr.equals("7f"));
assert(b == byteVal);
// The hexadecimal digits are: "7f"
For a comma (", "
) separated format with a prefix ("#"
) using lowercase hex digits the HexFormat
is:
HexFormat commaFormat = HexFormat.ofDelimiter(", ").withPrefix("#");
byte[] bytes = {0, 1, 2, 3, 124, 125, 126, 127};
String str = commaFormat.formatHex(bytes);
byte[] parsed = commaFormat.parseHex(str);
assert(Arrays.equals(bytes, parsed));
// The formatted string is: "#00, #01, #02, #03, #7c, #7d, #7e, #7f"
For a fingerprint of byte values that uses the delimiter colon (":"
) and uppercase characters the HexFormat
is:
HexFormat formatFingerprint = HexFormat.ofDelimiter(":").withUpperCase();
byte[] bytes = {0, 1, 2, 3, 124, 125, 126, 127};
String str = formatFingerprint.formatHex(bytes);
byte[] parsed = formatFingerprint.parseHex(str);
assert(Arrays.equals(bytes, parsed));
// The formatted string is: "00:01:02:03:7C:7D:7E:7F"
This is a value-based class; use of identity-sensitive operations (including reference equality (==
), identity hash code, or synchronization) on instances of HexFormat
may have unpredictable results and should be avoided. The equals
method should be used for comparisons.
This class is immutable and thread-safe.
Unless otherwise noted, passing a null argument to any method will cause a NullPointerException
to be thrown.
Modifier and Type | Method | Description |
---|---|---|
String |
delimiter() |
Returns the delimiter between hexadecimal values in formatted hexadecimal strings. |
boolean |
equals |
Returns true if the other object is a HexFormat with the same parameters. |
String |
formatHex |
Returns a hexadecimal string formatted from a byte array. |
String |
formatHex |
Returns a hexadecimal string formatted from a byte array range. |
<A extends Appendable> |
formatHex |
Appends formatted hexadecimal strings from a byte array to the Appendable . |
<A extends Appendable> |
formatHex |
Appends formatted hexadecimal strings from a byte array range to the Appendable . |
static int |
fromHexDigit |
Returns the value for the hexadecimal character or codepoint. |
static int |
fromHexDigits |
Returns the int value parsed from a string of up to eight hexadecimal characters. |
static int |
fromHexDigits |
Returns the int value parsed from a string range of up to eight hexadecimal characters. |
static long |
fromHexDigitsToLong |
Returns the long value parsed from a string of up to sixteen hexadecimal characters. |
static long |
fromHexDigitsToLong |
Returns the long value parsed from a string range of up to sixteen hexadecimal characters. |
int |
hashCode() |
Returns a hashcode for this HexFormat . |
static boolean |
isHexDigit |
Returns true if the character is a valid hexadecimal character or codepoint. |
boolean |
isUpperCase() |
Returns true if the hexadecimal digits are uppercase, otherwise false . |
static HexFormat |
of() |
Returns a hexadecimal formatter with no delimiter and lowercase characters. |
static HexFormat |
ofDelimiter |
Returns a hexadecimal formatter with the delimiter and lowercase characters. |
byte[] |
parseHex |
Returns a byte array containing hexadecimal values parsed from a range of the character array. |
byte[] |
parseHex |
Returns a byte array containing hexadecimal values parsed from the string. |
byte[] |
parseHex |
Returns a byte array containing hexadecimal values parsed from a range of the string. |
String |
prefix() |
Returns the prefix used for each hexadecimal value in formatted hexadecimal strings. |
String |
suffix() |
Returns the suffix used for each hexadecimal value in formatted hexadecimal strings. |
String |
toHexDigits |
Returns the two hexadecimal characters for the byte value. |
String |
toHexDigits |
Returns the four hexadecimal characters for the char value. |
String |
toHexDigits |
Returns the eight hexadecimal characters for the int value. |
String |
toHexDigits |
Returns the sixteen hexadecimal characters for the long value. |
String |
toHexDigits |
Returns up to sixteen hexadecimal characters for the long value. |
String |
toHexDigits |
Returns the four hexadecimal characters for the short value. |
<A extends Appendable> |
toHexDigits |
Appends two hexadecimal characters for the byte value to the Appendable . |
char |
toHighHexDigit |
Returns the hexadecimal character for the high 4 bits of the value considering it to be a byte. |
char |
toLowHexDigit |
Returns the hexadecimal character for the low 4 bits of the value considering it to be a byte. |
String |
toString() |
Returns a description of the formatter parameters for uppercase, delimiter, prefix, and suffix. |
HexFormat |
withDelimiter |
Returns a copy of this HexFormat with the delimiter. |
HexFormat |
withLowerCase() |
Returns a copy of this HexFormat to use lowercase hexadecimal characters. |
HexFormat |
withPrefix |
Returns a copy of this HexFormat with the prefix. |
HexFormat |
withSuffix |
Returns a copy of this HexFormat with the suffix. |
HexFormat |
withUpperCase() |
Returns a copy of this HexFormat to use uppercase hexadecimal characters. |
public static HexFormat of()
withDelimiter
, withUpperCase
, withLowerCase
, withPrefix
, and withSuffix
return copies of formatters with new parameters.public static HexFormat ofDelimiter(String delimiter)
withDelimiter
, withUpperCase
, withLowerCase
, withPrefix
, and withSuffix
return copies of formatters with new parameters.delimiter
- a delimiter, non-null, may be emptyHexFormat
with the delimiter and lowercase characterspublic HexFormat withDelimiter(String delimiter)
HexFormat
with the delimiter.delimiter
- the delimiter, non-null, may be emptyHexFormat
with the delimiterpublic HexFormat withPrefix(String prefix)
HexFormat
with the prefix.prefix
- a prefix, non-null, may be emptyHexFormat
with the prefixpublic HexFormat withSuffix(String suffix)
HexFormat
with the suffix.suffix
- a suffix, non-null, may be emptyHexFormat
with the suffixpublic HexFormat withUpperCase()
HexFormat
to use uppercase hexadecimal characters. The uppercase hexadecimal characters are "0-9", "A-F"
.HexFormat
with uppercase hexadecimal characterspublic HexFormat withLowerCase()
HexFormat
to use lowercase hexadecimal characters. The lowercase hexadecimal characters are "0-9", "a-f"
.HexFormat
with lowercase hexadecimal characterspublic String delimiter()
""
public String prefix()
""
public String suffix()
""
public boolean isUpperCase()
true
if the hexadecimal digits are uppercase, otherwise false
.true
if the hexadecimal digits are uppercase, otherwise false
public String formatHex(byte[] bytes)
formatHex(bytes, 0, bytes.length))
.bytes
- a non-null array of bytespublic String formatHex(byte[] bytes, int fromIndex, int toIndex)
bytes
- a non-null array of bytesfromIndex
- the initial index of the range, inclusivetoIndex
- the final index of the range, exclusiveIndexOutOfBoundsException
- if the array range is out of boundspublic <A extends Appendable> A formatHex(A out, byte[] bytes)
Appendable
. Each byte value is formatted as the prefix, two hexadecimal characters selected from uppercase or lowercase digits, and the suffix. A delimiter follows each formatted value, except the last. The formatted hexadecimal strings are appended in zero or more calls to the Appendable
methods.A
- The type of Appendable
out
- an Appendable
, non-nullbytes
- a byte arrayAppendable
UncheckedIOException
- if an I/O exception occurs appending to the outputpublic <A extends Appendable> A formatHex(A out, byte[] bytes, int fromIndex, int toIndex)
Appendable
. Each byte value is formatted as the prefix, two hexadecimal characters selected from uppercase or lowercase digits, and the suffix. A delimiter follows each formatted value, except the last. The formatted hexadecimal strings are appended in zero or more calls to the Appendable
methods.A
- The type of Appendable
out
- an Appendable
, non-nullbytes
- a byte array, non-nullfromIndex
- the initial index of the range, inclusivetoIndex
- the final index of the range, exclusive.Appendable
IndexOutOfBoundsException
- if the array range is out of boundsUncheckedIOException
- if an I/O exception occurs appending to the outputpublic byte[] parseHex(CharSequence string)
string
- a string containing the byte values with prefix, hexadecimal digits, suffix, and delimitersIllegalArgumentException
- if the prefix or suffix is not present for each byte value, the byte values are not hexadecimal characters, or if the delimiter is not present after all but the last byte valuepublic byte[] parseHex(CharSequence string, int fromIndex, int toIndex)
string
- a string range containing hexadecimal digits, delimiters, prefix, and suffix.fromIndex
- the initial index of the range, inclusivetoIndex
- the final index of the range, exclusive.IllegalArgumentException
- if the prefix or suffix is not present for each byte value, the byte values are not hexadecimal characters, or if the delimiter is not present after all but the last byte valueIndexOutOfBoundsException
- if the string range is out of boundspublic byte[] parseHex(char[] chars, int fromIndex, int toIndex)
chars
- a character array range containing an even number of hexadecimal digits, delimiters, prefix, and suffix.fromIndex
- the initial index of the range, inclusivetoIndex
- the final index of the range, exclusive.IllegalArgumentException
- if the prefix or suffix is not present for each byte value, the byte values are not hexadecimal characters, or if the delimiter is not present after all but the last byte valueIndexOutOfBoundsException
- if the character array range is out of boundspublic char toLowHexDigit(int value)
isUpperCase()
is true
the character returned for values 10-15
is uppercase "A-F"
, otherwise the character returned is lowercase "a-f"
. The values in the range 0-9
are returned as "0-9"
.value
- a value, only the low 4 bits 0-3
of the value are used0-3
of the valuepublic char toHighHexDigit(int value)
isUpperCase()
is true
the character returned for values 10-15
is uppercase "A-F"
, otherwise the character returned is lowercase "a-f"
. The values in the range 0-9
are returned as "0-9"
.value
- a value, only bits 4-7
of the value are used4-7
of the valuepublic <A extends Appendable> A toHexDigits(A out, byte value)
Appendable
. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble)
. The hexadecimal characters are appended in one or more calls to the Appendable
methods. The delimiter, prefix and suffix are not used.A
- The type of Appendable
out
- an Appendable
, non-nullvalue
- a byte valueAppendable
UncheckedIOException
- if an I/O exception occurs appending to the outputpublic String toHexDigits(byte value)
byte
value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble)
. The delimiter, prefix and suffix are not used.value
- a byte valuepublic String toHexDigits(char value)
char
value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble)
. The delimiter, prefix and suffix are not used.value
- a char
valuechar
valuepublic String toHexDigits(short value)
short
value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble)
. The delimiter, prefix and suffix are not used.value
- a short
valueshort
valuepublic String toHexDigits(int value)
int
value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble)
. The delimiter, prefix and suffix are not used.value
- an int
valueint
valuepublic String toHexDigits(long value)
long
value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble)
. The delimiter, prefix and suffix are not used.value
- a long
valuelong
valuepublic String toHexDigits(long value, int digits)
long
value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble)
. The delimiter, prefix and suffix are not used.value
- a long
valuedigits
- the number of hexadecimal digits to return, 0 to 16long
valueIllegalArgumentException
- if digits
is negative or greater than 16public static boolean isHexDigit(int ch)
true
if the character is a valid hexadecimal character or codepoint. The valid hexadecimal characters are: '0' ('\u0030')
through '9' ('\u0039')
inclusive, 'A' ('\u0041')
through 'F' ('\u0046')
inclusive, and 'a' ('\u0061')
through 'f' ('\u0066')
inclusive. ch
- a codepointtrue
if the character is valid a hexadecimal character, otherwise false
public static int fromHexDigit(int ch)
(ch - '0')
for '0'
through '9'
inclusive, (ch - 'A' + 10)
for 'A'
through 'F'
inclusive, and (ch - 'a' + 10)
for 'a'
through 'f'
inclusive. ch
- a character or codepoint0-15
NumberFormatException
- if the codepoint is not a hexadecimal characterpublic static int fromHexDigits(CharSequence string)
int
value parsed from a string of up to eight hexadecimal characters. The hexadecimal characters are parsed from most significant to least significant using fromHexDigit(int)
to form an unsigned value. The value is zero extended to 32 bits and is returned as an int
.Integer.parseInt(s, 16)
and Integer.parseUnsignedInt(s, 16)
are similar but allow all Unicode hexadecimal digits defined by Character.digit(ch, 16)
. HexFormat
uses only hexadecimal characters "0-9"
, "A-F"
and "a-f"
. Signed hexadecimal strings can be parsed with Integer.parseInt(String, int)
.string
- a CharSequence containing up to eight hexadecimal charactersIllegalArgumentException
- if the string length is greater than eight (8) or if any of the characters is not a hexadecimal characterpublic static int fromHexDigits(CharSequence string, int fromIndex, int toIndex)
int
value parsed from a string range of up to eight hexadecimal characters. The characters in the range fromIndex
to toIndex
, exclusive, are parsed from most significant to least significant using fromHexDigit(int)
to form an unsigned value. The value is zero extended to 32 bits and is returned as an int
.Integer.parseInt(s, 16)
and Integer.parseUnsignedInt(s, 16)
are similar but allow all Unicode hexadecimal digits defined by Character.digit(ch, 16)
. HexFormat
uses only hexadecimal characters "0-9"
, "A-F"
and "a-f"
. Signed hexadecimal strings can be parsed with Integer.parseInt(String, int)
.string
- a CharSequence containing the charactersfromIndex
- the initial index of the range, inclusivetoIndex
- the final index of the range, exclusive.IndexOutOfBoundsException
- if the range is out of bounds for the CharSequence
IllegalArgumentException
- if length of the range is greater than eight (8) or if any of the characters is not a hexadecimal characterpublic static long fromHexDigitsToLong(CharSequence string)
fromHexDigit(int)
to form an unsigned value. The value is zero extended to 64 bits and is returned as a long
.Long.parseLong(s, 16)
and Long.parseUnsignedLong(s, 16)
are similar but allow all Unicode hexadecimal digits defined by Character.digit(ch, 16)
. HexFormat
uses only hexadecimal characters "0-9"
, "A-F"
and "a-f"
. Signed hexadecimal strings can be parsed with Long.parseLong(String, int)
.string
- a CharSequence containing up to sixteen hexadecimal charactersIllegalArgumentException
- if the string length is greater than sixteen (16) or if any of the characters is not a hexadecimal characterpublic static long fromHexDigitsToLong(CharSequence string, int fromIndex, int toIndex)
fromIndex
to toIndex
, exclusive, are parsed from most significant to least significant using fromHexDigit(int)
to form an unsigned value. The value is zero extended to 64 bits and is returned as a long
.Long.parseLong(s, 16)
and Long.parseUnsignedLong(s, 16)
are similar but allow all Unicode hexadecimal digits defined by Character.digit(ch, 16)
. HexFormat
uses only hexadecimal characters "0-9"
, "A-F"
and "a-f"
. Signed hexadecimal strings can be parsed with Long.parseLong(String, int)
.string
- a CharSequence containing the charactersfromIndex
- the initial index of the range, inclusivetoIndex
- the final index of the range, exclusive.IndexOutOfBoundsException
- if the range is out of bounds for the CharSequence
IllegalArgumentException
- if the length of the range is greater than sixteen (16) or if any of the characters is not a hexadecimal characterpublic boolean equals(Object o)
true
if the other object is a HexFormat
with the same parameters.public int hashCode()
HexFormat
.public String toString()
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Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/HexFormat.html