Java MD5

    Java 的MessageDigest 提供了生产MD5的算法，但是它返回的是byte[]，以下方法实现了MD5值为16进制字符串的返回值。
    由于没有找到现成的转换方法，采用的是对每个字节比较来实现的.

    public class MD5Security {
        private final static char[] hexDigits = { '0', '1', '2', '3', '4', '5',
                '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

        private static String bytesToHex(byte[] bytes) {
            StringBuffer sb = new StringBuffer();
            int t;
            for (int i = 0; i < 16; i++) {// 16 == bytes.length;

                t = bytes[i];
                if (t < 0)
                    t +=256;
                sb.append(hexDigits[(t >>> 4)]);
                sb.append(hexDigits[(t % 16)]);
            }
            return sb.toString();
        }

        public static String code(String input) throws Exception {
            try {
                MessageDigest md = MessageDigest.getInstance(System.getProperty(
                        "MD5.algorithm", "MD5"));
                return bytesToHex(md.digest(input.getBytes("utf-8")));

            } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
                throw new Exception("Could not found MD5 algorithm.", e);
            }
        }
    }

【责编:Ken】