code: public static String toHexString(byte[] value) {
      String newString = "";
      for (int i = 0; i < value.length; i++) {
        byte b = value[i];
        String str = Integer.toHexString(b);
        if (str.length() > 2) {
          str = str.substring(str.length() - 2);
        }
        if (str.length() < 2) {
          str = "0" + str;
        }
        newString += str;
      }
      return newString.toUpperCase();
    }
docs: 16进制显示数据
  
  @param value
  字节数组