前端（主要用了element官方组件）：

      <el-upload
        class="upload-demo"
        ref="upload"
        :on-success="handleAvatarSuccess"//回调方法
        :action="uploadTxt()"//后台接口
        :on-remove="handleRemove"
        :before-remove="beforeRemove"
        accept=".txt">
        <el-button type="primary" style="margin-top: 20px">上传62数据用户(txt)</el-button>
      </el-upload>

后端controller(业务主要是读取txt插入数据）:

    @RequestMapping(value = "/uploadUserTxt",method = RequestMethod.POST)
    public Map<String, Object> uploadUserTxt(@RequestParam("file") MultipartFile file) throws Exception {
        return userInfoService.getUser(file);
    }

service(重点）:

    public Map<String, Object> getUser(MultipartFile multipartFile) throws Exception {
        Map<String, Object> resultMap = new HashMap<>();
        resultMap.put("result", Constants.FAILURE_RESULT);//返回数据而已
        resultMap.put("msg", Constants.UNKNOWN_FAILURE_RESULT);
        File file = null;
        file = File.createTempFile("tmp", null);
        multipartFile.transferTo(file); //MultipartFile转File
        file.deleteOnExit();
        BufferedReader reader = null;
        String temp = null;
        int line = 1;
        UserInfo userInfo = new UserInfo();
        try {
            int result = 0;
            reader = new BufferedReader(new InputStreamReader(new FileInputStream(file),"UTF-8"));//解决服务器上乱码
            while ((temp = reader.readLine()) != null) {
                System.out.println("line" + line + ":" + temp);
                //解析数据就不写了
                line++;
            }
            if (result > 0) {
                resultMap.put("result", Constants.SUCCESS_RESULT);
                resultMap.put("msg", Constants.UPDATE_SUCCESS);
            }else {
                resultMap.put("msg", Constants.UPDATE_FAILED);
            }
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
        return resultMap;
    }