分享一个 常用的 hex 转 characters或integer

这个如果不熟的话还是要查找许多资料和时间来解决这个问题的，下面分享这样一个类。

这样方便大家节省许多功夫去查找资料。

代码：

package org.apache.commons.codec.binary;import org.apache.commons.codec.BinaryDecoder;import org.apache.commons.codec.BinaryEncoder;import org.apache.commons.codec.DecoderException;import org.apache.commons.codec.EncoderException;/** * Hex encoder and decoder. *  */public class Hex implements BinaryEncoder, BinaryDecoder {    /**      * Used building output as Hex      */    private static final char[] DIGITS = {        '0', '1', '2', '3', '4', '5', '6', '7',           '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'    };    /**     * Converts an array of characters representing hexidecimal 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 hexidecimal 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(char[] data) throws DecoderException {        int len = data.length;        if ((len & 0x01) != 0) {            throw new DecoderException("Odd number of characters.");        }        byte[] out = new byte[len >> 1];        // two characters form the hex value.        for (int i = 0, j = 0; j < len; i++) {            int f = toDigit(data[j], j) << 4;            j++;            f = f | toDigit(data[j], j);            j++;            out[i] = (byte) (f & 0xFF);        }        return out;    }    /**     * Converts a hexadecimal character to an integer.     *       * @param ch A character to convert to an integer digit     * @param index The index of the character in the source     * @return An integer     * @throws DecoderException Thrown if ch is an illegal hex character     */    protected static int toDigit(char ch, int index) throws DecoderException {        int digit = Character.digit(ch, 16);        if (digit == -1) {            throw new DecoderException("Illegal hexadecimal charcter " + ch + " at index " + index);        }        return digit;    }    /**     * Converts an array of bytes into an array of characters representing the hexidecimal 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.     *      * @param data     *                  a byte[] to convert to Hex characters     * @return A char[] containing hexidecimal characters     */    public static char[] encodeHex(byte[] data) {        int l = data.length;           char[] out = new char[l << 1];           // two characters form the hex value.           for (int i = 0, j = 0; i < l; i++) {               out[j++] = DIGITS[(0xF0 & data[i]) >>> 4 ];               out[j++] = DIGITS[ 0x0F & data[i] ];           }           return out;    }        /**     * Converts an array of character bytes representing hexidecimal 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 array An array of character bytes containing hexidecimal digits     * @return 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 #decodeHex(char[])     */    public byte[] decode(byte[] array) throws DecoderException {        return decodeHex(new String(array).toCharArray());    }        /**     * Converts a String or an array of character bytes representing hexidecimal 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.     *      * @param object A String or, an array of character bytes containing hexidecimal digits     * @return 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 #decodeHex(char[])     */    public Object decode(Object object) throws DecoderException {        try {            char[] charArray = object instanceof String ? ((String) object).toCharArray() : (char[]) object;            return decodeHex(charArray);        } catch (ClassCastException e) {            throw new DecoderException(e.getMessage());        }    }        /**     * Converts an array of bytes into an array of bytes for the characters representing the     * hexidecimal 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.     *     * @param array a byte[] to convert to Hex characters     * @return A byte[] containing the bytes of the hexidecimal characters     * @see #encodeHex(byte[])     */    public byte[] encode(byte[] array) {        return new String(encodeHex(array)).getBytes();    }    /**     * Converts a String or an array of bytes into an array of characters representing the     * hexidecimal 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.     *     * @param object a String, or byte[] to convert to Hex characters     * @return A char[] containing hexidecimal characters     * @throws EncoderException Thrown if the given object is not a String or byte[]     * @see #encodeHex(byte[])     */    public Object encode(Object object) throws EncoderException {            try {            byte[] byteArray = object instanceof String ? ((String) object).getBytes() : (byte[]) object;            return encodeHex(byteArray);        } catch (ClassCastException e) {            throw new EncoderException(e.getMessage());        }    }}

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资料：

http://www.yidin.net/?p=8280

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