<form action="http://localhost:3000/profile" method="post" enctype="multipart/form-data">

  <input type="file" name="avatar" />

  <input type="submit" value="av2tar" />

</form>

//假设你的express 服务器已经跑起来了

var express = require('express');

const fs = require('fs');

const path = require('path');

var controllers = path.join(path.resolve(__dirname, '..'), 'controllers');

var uploadDir = path.join(path.resolve(__dirname, 'uploads'));

var router = express.Router();

var multer  = require('multer');

var storage = multer.diskStorage({

  destination: function (req, file, cb) {

    cb(null, './uploads')  //自己定义目录

  },

  filename: function (req, file, cb) {

    console.log(file)

    cb(null, file.originalname + '-' + Date.now())

  /*

　　{ 
     fieldname: 'avatar',

     originalname: 'flink-1.8.0-bin-scala_2.12.tgz',

     encoding: '7bit',

     mimetype: 'application/gzip' 
   }

*/

  }

})

var upload = multer({ storage: storage })

/* GET users listing. */

router.post('/', upload.single('avatar'), function(req, res, next) {

  res.send('Upload success...');

});

module.exports = router;
官网网站：https://www.npmjs.com/package/multer