android hmacSha256 加密

public class HMACSHA256 {
    public static String hmacSha256(String KEY, String VALUE) {
        return hmacSha(KEY, VALUE, "HmacSHA256");
    }

    private static String hmacSha(String KEY, String VALUE, String SHA_TYPE) {
        try {
            SecretKeySpec signingKey = new SecretKeySpec(KEY.getBytes("UTF-8"), SHA_TYPE);
            Mac mac = Mac.getInstance(SHA_TYPE);
            mac.init(signingKey);
            byte[] rawHmac = mac.doFinal(VALUE.getBytes("UTF-8"));

            byte[] hexArray = {
                    (byte)'0', (byte)'1', (byte)'2', (byte)'3',
                    (byte)'4', (byte)'5', (byte)'6', (byte)'7',
                    (byte)'8', (byte)'9', (byte)'a', (byte)'b',
                    (byte)'c', (byte)'d', (byte)'e', (byte)'f'
            };
            byte[] hexChars = new byte[rawHmac.length * 2];
            for ( int j = 0; j < rawHmac.length; j++ ) {
                int v = rawHmac[j] & 0xFF;
                hexChars[j * 2] = hexArray[v >>> 4];
                hexChars[j * 2 + 1] = hexArray[v & 0x0F];
            }
            return new String(hexChars);
        }
        catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }
}