code: @Override
      public void handle(RequestDTO requestDTO, Attachment attachment) {
          if (handler != null) {
              handler.handle(requestDTO, attachment);
          }
          if (attachment != null && attachment.getAppIdToken() != null
                  && StringUtil.isNotEmpty(attachment.getAppIdToken().getAppId())
                  && StringUtil.isNotEmpty(attachment.getAppIdToken().getToken())) {
              requestDTO.setAppId(attachment.getAppIdToken().getAppId());
              requestDTO.setToken(attachment.getAppIdToken().getToken());
          }
      }
docs: 处理附加信息
  
  @param requestDTO
  请求DTO
  @param attachment
  附加信息
  @see com.baidu.beidou.navi.client.attachment.AttachmentHandler#handle(com.baidu.beidou.navi.server.vo.RequestDTO,
  com.baidu.beidou.navi.client.attachment.Attachment)