字节数组转化为16进制字符串

 public static String bytesToHexString(byte[] bytes) {        String result = "";        for (int i = 0; i < bytes.length; i++) {            String hexString = Integer.toHexString(bytes[i] & 0xFF);            if (hexString.length() == 1) {                hexString = '0' + hexString;            }            result += hexString.toUpperCase();        }        return result;    }