Class Hex


  • public class Hex
    extends Object

    Overview

    Converts hexadecimal Strings. The Charset used for certain operation can be set, the default is set in StandardCharsets.UTF_8 This class is thread-safe.

    Usage

     String roundtrip = "roundtrip";
     assertEquals(roundtrip, new String(Hex.decodeHex(Hex.encodeHex(roundtrip.getBytes()))));
     
    Author:
    https://github.com/apache/commons-codec/blob/master/src/main/java/org/apache/commons/codec/binary/Hex.java
    • Constructor Summary

      Constructors 
      Constructor Description
      Hex()
      Creates a new codec with the default charset name DEFAULT_CHARSET
      Hex​(String charsetName)
      Creates a new codec with the given charset name.
      Hex​(Charset charset)
      Creates a new codec with the given Charset.
    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      byte[] decode​(byte[] array)
      Converts an array of character bytes representing hexadecimal values into an array of bytes of those same values.
      Object decode​(Object object)
      Converts a String or an array of character bytes representing hexadecimal values into an array of bytes of those same values.
      byte[] decode​(ByteBuffer buffer)
      Converts a buffer of character bytes representing hexadecimal values into an array of bytes of those same values.
      static byte[] decodeHex​(char[] data)
      Converts an array of characters representing hexadecimal values into an array of bytes of those same values.
      static byte[] decodeHex​(String data)
      Converts a String representing hexadecimal values into an array of bytes of those same values.
      byte[] encode​(byte[] array)
      Converts an array of bytes into an array of bytes for the characters representing the hexadecimal values of each byte in order.
      Object encode​(Object object)
      Converts a String or an array of bytes into an array of characters representing the hexadecimal values of each byte in order.
      byte[] encode​(ByteBuffer array)
      Converts byte buffer into an array of bytes for the characters representing the hexadecimal values of each byte in order.
      static char[] encodeHex​(byte[] data)
      Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.
      static char[] encodeHex​(byte[] data, boolean toLowerCase)
      Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.
      protected static char[] encodeHex​(byte[] data, char[] toDigits)
      Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.
      static char[] encodeHex​(ByteBuffer data)
      Converts a byte buffer into an array of characters representing the hexadecimal values of each byte in order.
      static char[] encodeHex​(ByteBuffer data, boolean toLowerCase)
      Converts a byte buffer into an array of characters representing the hexadecimal values of each byte in order.
      protected static char[] encodeHex​(ByteBuffer byteBuffer, char[] toDigits)
      Converts a byte buffer into an array of characters representing the hexadecimal values of each byte in order.
      static String encodeHexString​(byte[] data)
      Converts an array of bytes into a String representing the hexadecimal values of each byte in order.
      static String encodeHexString​(byte[] data, boolean toLowerCase)
      Converts an array of bytes into a String representing the hexadecimal values of each byte in order.
      static String encodeHexString​(ByteBuffer data)
      Converts a byte buffer into a String representing the hexadecimal values of each byte in order.
      static String encodeHexString​(ByteBuffer data, boolean toLowerCase)
      Converts a byte buffer into a String representing the hexadecimal values of each byte in order.
      Charset getCharset()  
      protected static int toDigit​(char ch, int index)
      Converts a hexadecimal character to an integer.
      String toString()  
    • Constructor Detail

      • Hex

        public Hex​(Charset charset)
        Creates a new codec with the given Charset.
        Parameters:
        charset - the charset.
      • Hex

        public Hex​(String charsetName)
        Creates a new codec with the given charset name.
        Parameters:
        charsetName - the charset name.
        Throws:
        UnsupportedCharsetException - If the named charset is unavailable throws UnsupportedCharsetException if the named charset is unavailable
    • Method Detail

      • decodeHex

        public static byte[] decodeHex​(String data)
                                throws DecoderException
        Converts a String representing hexadecimal values into an array of bytes of those same values. The returned array will be half the length of the passed String, as it takes two characters to represent any given byte. An exception is thrown if the passed String has an odd number of elements.
        Parameters:
        data - A String containing hexadecimal digits
        Returns:
        A byte array containing binary data decoded from the supplied char array.
        Throws:
        DecoderException - Thrown if an odd number or illegal of characters is supplied
      • decodeHex

        public static byte[] decodeHex​(char[] data)
                                throws DecoderException
        Converts an array of characters representing hexadecimal values into an array of bytes of those same values. The returned array will be half the length of the passed array, as it takes two characters to represent any given byte. An exception is thrown if the passed char array has an odd number of elements.
        Parameters:
        data - An array of characters containing hexadecimal digits
        Returns:
        A byte array containing binary data decoded from the supplied char array.
        Throws:
        DecoderException - Thrown if an odd number or illegal of characters is supplied
      • encodeHex

        public static char[] encodeHex​(byte[] data)
        Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order. The returned array will be double the length of the passed array, as it takes two characters to represent any given byte.
        Parameters:
        data - a byte[] to convert to Hex characters
        Returns:
        A char[] containing lower-case hexadecimal characters
      • encodeHex

        public static char[] encodeHex​(ByteBuffer data)
        Converts a byte buffer into an array of characters representing the hexadecimal values of each byte in order. The returned array will be double the length of the passed array, as it takes two characters to represent any given byte.

        All bytes identified by Buffer.remaining() will be used; after this method the value remaining() will be zero.

        Parameters:
        data - a byte buffer to convert to Hex characters
        Returns:
        A char[] containing lower-case hexadecimal characters
      • encodeHex

        public static char[] encodeHex​(byte[] data,
                                       boolean toLowerCase)
        Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order. The returned array will be double the length of the passed array, as it takes two characters to represent any given byte.
        Parameters:
        data - a byte[] to convert to Hex characters
        toLowerCase - true converts to lowercase, false to uppercase
        Returns:
        A char[] containing hexadecimal characters in the selected case
      • encodeHex

        public static char[] encodeHex​(ByteBuffer data,
                                       boolean toLowerCase)
        Converts a byte buffer into an array of characters representing the hexadecimal values of each byte in order. The returned array will be double the length of the passed array, as it takes two characters to represent any given byte.

        All bytes identified by Buffer.remaining() will be used; after this method the value remaining() will be zero.

        Parameters:
        data - a byte buffer to convert to Hex characters
        toLowerCase - true converts to lowercase, false to uppercase
        Returns:
        A char[] containing hexadecimal characters in the selected case
      • encodeHex

        protected static char[] encodeHex​(byte[] data,
                                          char[] toDigits)
        Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order. The returned array will be double the length of the passed array, as it takes two characters to represent any given byte.
        Parameters:
        data - a byte[] to convert to Hex characters
        toDigits - the output alphabet (must contain at least 16 chars)
        Returns:
        A char[] containing the appropriate characters from the alphabet For best results, this should be either upper- or lower-case hex.
      • encodeHex

        protected static char[] encodeHex​(ByteBuffer byteBuffer,
                                          char[] toDigits)
        Converts a byte buffer into an array of characters representing the hexadecimal values of each byte in order. The returned array will be double the length of the passed array, as it takes two characters to represent any given byte.

        All bytes identified by Buffer.remaining() will be used; after this method the value remaining() will be zero.

        Parameters:
        byteBuffer - a byte buffer to convert to Hex characters
        toDigits - the output alphabet (must be at least 16 characters)
        Returns:
        A char[] containing the appropriate characters from the alphabet For best results, this should be either upper- or lower-case hex.
      • encodeHexString

        public static String encodeHexString​(byte[] data)
        Converts an array of bytes into a String representing the hexadecimal values of each byte in order. The returned String will be double the length of the passed array, as it takes two characters to represent any given byte.
        Parameters:
        data - a byte[] to convert to Hex characters
        Returns:
        A String containing lower-case hexadecimal characters
      • encodeHexString

        public static String encodeHexString​(byte[] data,
                                             boolean toLowerCase)
        Converts an array of bytes into a String representing the hexadecimal values of each byte in order. The returned String will be double the length of the passed array, as it takes two characters to represent any given byte.
        Parameters:
        data - a byte[] to convert to Hex characters
        toLowerCase - true converts to lowercase, false to uppercase
        Returns:
        A String containing lower-case hexadecimal characters
      • encodeHexString

        public static String encodeHexString​(ByteBuffer data)
        Converts a byte buffer into a String representing the hexadecimal values of each byte in order. The returned String will be double the length of the passed array, as it takes two characters to represent any given byte.

        All bytes identified by Buffer.remaining() will be used; after this method the value remaining() will be zero.

        Parameters:
        data - a byte buffer to convert to Hex characters
        Returns:
        A String containing lower-case hexadecimal characters
      • encodeHexString

        public static String encodeHexString​(ByteBuffer data,
                                             boolean toLowerCase)
        Converts a byte buffer into a String representing the hexadecimal values of each byte in order. The returned String will be double the length of the passed array, as it takes two characters to represent any given byte.

        All bytes identified by Buffer.remaining() will be used; after this method the value remaining() will be zero.

        Parameters:
        data - a byte buffer to convert to Hex characters
        toLowerCase - true converts to lowercase, false to uppercase
        Returns:
        A String containing lower-case hexadecimal characters
      • toDigit

        protected static int toDigit​(char ch,
                                     int index)
                              throws DecoderException
        Converts a hexadecimal character to an integer.
        Parameters:
        ch - A character to convert to an integer digit
        index - The index of the character in the source
        Returns:
        An integer
        Throws:
        DecoderException - Thrown if ch is an illegal hex character
      • decode

        public byte[] decode​(byte[] array)
                      throws DecoderException
        Converts an array of character bytes representing hexadecimal values into an array of bytes of those same values. The returned array will be half the length of the passed array, as it takes two characters to represent any given byte. An exception is thrown if the passed char array has an odd number of elements.
        Parameters:
        array - An array of character bytes containing hexadecimal digits
        Returns:
        A byte array containing binary data decoded from the supplied byte array (representing characters).
        Throws:
        DecoderException - Thrown if an odd number of characters is supplied to this function
        See Also:
        decodeHex(char[])
      • decode

        public byte[] decode​(ByteBuffer buffer)
                      throws DecoderException
        Converts a buffer of character bytes representing hexadecimal values into an array of bytes of those same values. The returned array will be half the length of the passed array, as it takes two characters to represent any given byte. An exception is thrown if the passed char array has an odd number of elements.

        All bytes identified by Buffer.remaining() will be used; after this method the value remaining() will be zero.

        Parameters:
        buffer - An array of character bytes containing hexadecimal digits
        Returns:
        A byte array containing binary data decoded from the supplied byte array (representing characters).
        Throws:
        DecoderException - Thrown if an odd number of characters is supplied to this function
        See Also:
        decodeHex(char[])
      • decode

        public Object decode​(Object object)
                      throws DecoderException
        Converts a String or an array of character bytes representing hexadecimal values into an array of bytes of those same values. The returned array will be half the length of the passed String or array, as it takes two characters to represent any given byte. An exception is thrown if the passed char array has an odd number of elements.
        Parameters:
        object - A String, ByteBuffer, byte[], or an array of character bytes containing hexadecimal digits
        Returns:
        A byte array containing binary data decoded from the supplied byte array (representing characters).
        Throws:
        DecoderException - Thrown if an odd number of characters is supplied to this function or the object is not a String or char[]
        See Also:
        decodeHex(char[])
      • encode

        public byte[] encode​(byte[] array)
        Converts an array of bytes into an array of bytes for the characters representing the hexadecimal values of each byte in order. The returned array will be double the length of the passed array, as it takes two characters to represent any given byte.

        The conversion from hexadecimal characters to the returned bytes is performed with the charset named by getCharset().

        Parameters:
        array - a byte[] to convert to Hex characters
        Returns:
        A byte[] containing the bytes of the lower-case hexadecimal characters No longer throws IllegalStateException if the charsetName is invalid.
        See Also:
        encodeHex(byte[])
      • encode

        public byte[] encode​(ByteBuffer array)
        Converts byte buffer into an array of bytes for the characters representing the hexadecimal values of each byte in order. The returned array will be double the length of the passed array, as it takes two characters to represent any given byte.

        The conversion from hexadecimal characters to the returned bytes is performed with the charset named by getCharset().

        All bytes identified by Buffer.remaining() will be used; after this method the value remaining() will be zero.

        Parameters:
        array - a byte buffer to convert to Hex characters
        Returns:
        A byte[] containing the bytes of the lower-case hexadecimal characters
        See Also:
        encodeHex(byte[])
      • encode

        public Object encode​(Object object)
                      throws EncoderException
        Converts a String or an array of bytes into an array of characters representing the hexadecimal values of each byte in order. The returned array will be double the length of the passed String or array, as it takes two characters to represent any given byte.

        The conversion from hexadecimal characters to bytes to be encoded to performed with the charset named by getCharset().

        Parameters:
        object - a String, ByteBuffer, or byte[] to convert to Hex characters
        Returns:
        A char[] containing lower-case hexadecimal characters
        Throws:
        EncoderException - Thrown if the given object is not a String or byte[]
        See Also:
        encodeHex(byte[])