springboot vue 下载文件，浏览器未显示下载的文件 只有控制台 Preview 有文件

Question

springboot vue 下载文件，浏览器未显示下载的文件
只有控制台 Preview 有文件

    @PostMapping("/down")
   public void down(HttpServletResponse response, @Param("id") int id) {
        Backup backup = backupService.getById(id);
          File file=new File(backup.getPath());
        response.setContentType ("application/octet-stream");
         
        String name = file.getName()+".txt";
        try {
            name = new String (name.getBytes (StandardCharsets.UTF_8), "ISO8859-1");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace ();
        }
        response.addHeader ("Content-Disposition", "attachment;filename=" + name);

        OutputStream opmt = null;

        try {
            opmt = response.getOutputStream ();
            opmt.write (FileUtils.readFileToByteArray (new File (backup.getPath())));
            opmt.close ();
        } catch (IOException e) {
            e.printStackTrace ();
        }
        
}

    async download({id}){ // id=
      const result = await getBackupDown({id}).catch(err=>{
        this.$message.error('网络请求错误')
      })
      if(result.status){
        this.$message.error('下载失败')
      }else {
        this.$message.success('下载成功')
      }

      await this.fetchData()
    },

<a-button value="small" @click="download(item)">下载</a-button>

Answer 1

this.$message.success('下载成功')
    const blob = new Blob([res.data], { type: 'application/vnd.ms-excel;charset=utf-8' })
    let link = document.createElement("a");
    let href = window.URL.createObjectURL(blob); //下载链接
    link.href = href;
    link.text = "下载";
    link.download = "xxx"; //下载后文件名
    document.body.appendChild(link);
    link.click(); //点击下载
    document.body.removeChild(link); //下载完成移除元素
    window.URL.revokeObjectURL(href);  //释放blob对象