Class Hex

src/main/java/org/apache/commons/codec/binary/Hex.java:39–498

Converts hexadecimal Strings. The Charset used for certain operation can be set, the default is set in #DEFAULT_CHARSET_NAME This class is thread-safe. @since 1.1

 * @since 1.1
 */
public class Hex implements BinaryEncoder, BinaryDecoder {

    /**
     * Default charset is {@link StandardCharsets#UTF_8}
     *
     * @since 1.7
     */
    public static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;

    /**
     * Default charset name is {@link CharEncoding#UTF_8}
     *
     * @since 1.4
     */
    public static final String DEFAULT_CHARSET_NAME = CharEncoding.UTF_8;

    /**
     * Used to build output as Hex
     */
    private static final char[] DIGITS_LOWER = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd',
            'e', 'f' };

    /**
     * Used to build output as Hex
     */
    private static final char[] DIGITS_UPPER = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
            'E', 'F' };

    /**
     * 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.
     *
     * @param data A String containing hexadecimal digits
     * @return 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
     * @since 1.11
     */
    public static byte[] decodeHex(final String data) throws DecoderException {
        return decodeHex(data.toCharArray());
    }

    /**
     * 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.
     *
     * @param data An array of characters containing hexadecimal digits
     * @return 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
     */
    public static byte[] decodeHex(final char[] data) throws DecoderException {

        final int len = data.length;

        if ((len & 0x01) != 0) {
            throw new DecoderException("Odd number of characters.");
        }