java hash_hmac

 public static String getSignature(String data, String key) throws Exception {        byte[] keyBytes = key.getBytes();        SecretKeySpec signingKey = new SecretKeySpec(keyBytes, MAC_NAME);        Mac mac = Mac.getInstance(MAC_NAME);        mac.init(signingKey);        byte[] rawHmac = mac.doFinal(data.getBytes());        StringBuilder sb = new StringBuilder();        for (byte b : rawHmac) {            sb.append(byteToHexString(b));        }        return sb.toString();    }    private static String byteToHexString(byte ib) {        char[] Digit = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};        char[] ob = new char[2];        ob[0] = Digit[(ib >>> 4) & 0X0f];        ob[1] = Digit[ib & 0X0F];        return new String(ob);    }