Java安全后端返回文件流方式

import org.apache.commons.io.IOUtils;
    @Value("${file.ectdreport-folder}")
    private String ectdReportFolder;
    @Transactional(rollbackFor = Exception.class)
    public void lookReport(String id, HttpServletResponse response) throws Exception {
        String url = ectdReportFolder + id + "/file1.html";
        File file = new File(url);
        if (!file.exists()) {
            throw new Exception("文件不存在");//抛出文件不存在的
        }
        response.setContentType("text/html");
        FileInputStream fis = null;
        OutputStream outputStream = response.getOutputStream();
        try {
            fis = new FileInputStream(file);
            //将读取流拷贝到输出流中
            IOUtils.copy(fis, outputStream);
            //清空缓存的读取流，保证数据完整性
            response.flushBuffer();
        } catch (IOException e) {
            e.printStackTrace();
           throw new Exception("解析失败");
        } finally {
            if (fis != null) {
                try {
                    fis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (outputStream != null) {
                outputStream.close();//输出流关闭
            }
        }
    }

  // 在请求的时候做一些处理
  // get请求
  markMownLoad = (id) => axios('get',`URLxxxxxx?fileId=${id}`,{
    responseType: 'blob',
    headers:{
      'Content-Type': 'multipart/form-data'
    }
  })
  // post请求
  markMownLoads = (id) => axios('post',`URLxxxxxx?fileId=${id}`,{
    responseType: 'blob',
    headers:{
      'Content-Type': 'multipart/form-data'
    }
  })

  function downLoadXls (res) {
    const fileNames = res.headers['content-disposition']
    if(fileNames) {
      //解码
      const fileName = decodeURIComponent(fileNames.match(/=(.*)$/)[1])
      // 处理返回的文件流
      const content =res.data
      const blob = new Blob([content],{
        type: "application/octet-stream; charset=utf-8"
      });
      if('download' in document.createElement('a')) {
        //非IE下载
        const a = document.createElement('a') //创建一个a标签
        a.download = fileName //指定文件名称
        a.style.display = 'none' //页面隐藏
        a.href = URL.createObjectURL(blob) // href用于下载地址
        document.body.appendChild(a) //插到页面上
        a.click() //通过点击触发
        URL.revokeObjectURL(a.href) //释放URL 对象
        document.body.removeChild(a) //删掉a标签
      }else{
        //IE10 + 下载
        navigator.msSaveBlob(blob,fileName)
      }
    }
  }

 // 发请求          把后端返回的传过去解码，然后实现导出、下载
  markMownLoads(参数).then(res => downLoadXls(res))