[alibaba/easyexcel]在使用response.getOutputStream() 来导出excel时，如何获取到最后导出文件的大小

/**

• 查询优化的方法 */ public void exportExcelByMultithreading(HttpServletResponse response, ThreadPoolTaskExecutor threadPoolTaskExecutor, Class pojoClass, Integer pageSize, QueryWrapper queryWrapper) throws IOException { ServletOutputStream out = getServletOutputStream(response); // // 导出文件路径 // String fileName = "d:\test.xlsx";

  Long count = baseMapper.selectCount(queryWrapper);
  Long sheetNum = count % pageSize == 0 ? count / pageSize:count / pageSize + 1;
  // 多线程去读
  // 1.初始化map容量 防止扩容带来的效率损耗
  Map<Integer, Page<T>> pageMap = new ConcurrentHashMap<>(Math.toIntExact(3));
  CountDownLatch countDownLatch = new CountDownLatch(Math.toIntExact(3));
  // 注意 easyexcel 暂时不支持多线程并发写入！！！ 详情请看github上issues
  for (int i = 200 ;i< sheetNum;i++){
      int finali = i;
      threadPoolTaskExecutor.submit(()->{
          Page<T> page = new Page<>();
          page.setCurrent(finali + 1);
          page.setSize(pageSize);
          // 获取数据存放到map中
          Page<T> selectPage = baseMapper.selectPage(page,queryWrapper);
          pageMap.put(finali,selectPage);
          // 消耗掉一个
          countDownLatch.countDown();
      });
  }
  try {
      countDownLatch.await();
  } catch (InterruptedException e) {
      e.printStackTrace();
  }
  // 写入
  try (ExcelWriter excelWriter = EasyExcel.write(out, pojoClass).build()) {
      pageMap.forEach((k,v)->{
          log.info("正在写入{}条数据",pageSize);
          WriteSheet writeSheet = EasyExcel.writerSheet(k, "第"+(k+1)+"批数据").build();
          excelWriter.write(v.getRecords(), writeSheet);
          pageMap.remove(k);
      });
  
      excelWriter.finish();
  }

  }