java字符串和十六进制字符串互转

public class HexStringUtils {    private static final char[] DIGITS_HEX = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',            'E', 'F' };    protected static char[] encodeHex(byte[] data) {        int l = data.length;        char[] out = new char[l << 1];        for (int i = 0, j = 0; i < l; i++) {            out[j++] = DIGITS_HEX[(0xF0 & data[i]) >>> 4];            out[j++] = DIGITS_HEX[0x0F & data[i]];        }        return out;    }    protected static byte[] decodeHex(char[] data) {        int len = data.length;        if ((len & 0x01) != 0) {            throw new RuntimeException("字符个数应该为偶数");        }        byte[] out = new byte[len >> 1];        for (int i = 0, j = 0; j < len; i++) {            int f = toDigit(data[j], j) << 4;            j++;            f |= toDigit(data[j], j);            j++;            out[i] = (byte) (f & 0xFF);        }        return out;    }    protected static int toDigit(char ch, int index) {        int digit = Character.digit(ch, 16);        if (digit == -1) {            throw new RuntimeException("Illegal hexadecimal character " + ch + " at index " + index);        }        return digit;    }    public static String toHex(String str) {        return new String(encodeHex(str.getBytes()));    }    public static String fromHex(String hex) {        return new String(decodeHex(hex.toCharArray()));    }    public static void main(String[] args) {        String s = "abc你好";        String hex = toHex(s);        String decode = fromHex(hex);        System.out.println("原字符串:" + s);        System.out.println("十六进制字符串:" + hex);        System.out.println("还原:" + decode);    }}