code: private static String bytes2Hex(byte[] bts) {
  		String des = "";
  		String tmp = null;
  
  		for (byte bt : bts) {
  			tmp = (Integer.toHexString(bt & 0xFF));
  			if (tmp.length() == 1) {
  				des += "0";
  			}
  			des += tmp;
  		}
  		return des;
  	}
docs: 将字节数组转换成16进制的字符串