java md5 函数

    private static final String md5(final String s) {

        final String MD5 = "MD5";

        try {

            // Create MD5 Hash

            MessageDigest digest = java.security.MessageDigest

                    .getInstance(MD5);

            digest.update(s.getBytes());

            byte messageDigest[] = digest.digest();

            // Create Hex String

            StringBuilder hexString = new StringBuilder();

            for (byte aMessageDigest : messageDigest) {

                String h = Integer.toHexString(0xFF & aMessageDigest);

                while (h.length() < 2)

                    h = "0" + h;

                hexString.append(h);

            }

            return hexString.toString();

        } catch (NoSuchAlgorithmException e) {

            e.printStackTrace();

        }

        return "";

    }