code: @SuppressWarnings("unchecked")
      protected JsonObject sysError(String msg) {
          JsonObject json = JsonObject.create();
          json.setStatus(GlobalResponseStatusMsg.SYSTEM_ERROR.getMessage().getCode());
          Map<String, Object> errors = new HashMap<String, Object>();
          errors.put(WebResponseConstant.MESSAGE_GLOBAL, msg);
          json.setStatusInfo(errors);
          return json;
      }
docs: 构造带有消息的系统错误
  
  @param msg
  错误消息
  @return JsonObject