SpringBoot下载的excel文件，提示部分内容有问题，需要修复

SpringBoot下载的excel文件打开时提示需要修复，如下图：

解决办法：给response的Header设置大小：

            //加上设置大小 下载下来的excel文件才不会在打开前提示修复
            response.addHeader("Content-Length",String.valueOf(file.length()));

完整代码如下：

    /**
     * 下载文件
     * */
    @RequestMapping(value = "download")
    @ResponseBody
    public String download(HttpServletResponse response) throws UnsupportedEncodingException {

        String filename = “text.xlsx”
        String path = "D:\\Temp\\rpaDownload\\";

        File file = new File(path + filename);

        if(file.exists()){
            response.setContentType("application/octet-stream");
            response.setHeader("content-type", "application/octet-stream");
            response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(filename,"utf8"));
            //加上设置大小 下载下来的excel文件才不会在打开前提示修复
            response.addHeader("Content-Length",String.valueOf(file.length()));
            byte[] buffer = new byte[1024];
            //输出流
            OutputStream os = null;
            FileInputStream fis = null;
            BufferedInputStream bis = null;
            try{
                fis= new FileInputStream(file);
                bis = new BufferedInputStream(fis);
                os = response.getOutputStream();
                int i = bis.read(buffer);
                while(i != -1){
                    os.write(buffer);
                    os.flush();
                    i = bis.read(buffer);
                }

            } catch (Exception e) {
                e.printStackTrace();
            }finally {
                try {
                    if (os != null) {
                        os.close();
                    }
                    if (fis != null) {
                        fis.close();
                    }
                    if (bis != null) {
                        bis.close();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
                Boolean  result = file.delete();
                  if (!result){
                      return "failed";
                  }
            }

        }

        return "index";
    }