docs: @NoAuth
      @RequestMapping(value = "/file", method = RequestMethod.GET)
      @ResponseBody
      public HttpEntity<byte[]> getFile(ConfForm confForm) {
  
          boolean hasError = false;
  
          //
          // 校验
          //
          ConfigFullModel configModel = null;
          try {
              configModel = configValidator4Fetch.verifyConfForm(confForm, false);
          } catch (Exception e) {
              LOG.error(e.toString());
              hasError = true;
          }
  
          if (hasError == false) {
              try {
                  //
                  Config config = configFetchMgr
                          .getConfByParameter(configModel.getApp().getId(), configModel.getEnv().getId(),
                                  configModel.getVersion(), configModel.getKey(),
                                  DisConfigTypeEnum.FILE);
                  if (config == null) {
                      hasError = true;
                      throw new DocumentNotFoundException(configModel.getKey());
                  }
                  //API获取节点内容也需要同样做格式转换
                  return downloadDspBill(configModel.getKey(), config.getValue());
  
              } catch (Exception e) {
                  LOG.error(e.toString());
              }
          }
  
          if (confForm.getKey() != null) {
              throw new DocumentNotFoundException(confForm.getKey());
          } else {
              throw new DocumentNotFoundException("");
          }
      }