一、服务端环境准备

本文服务端主要为nodejs,利用multer中间件完成图片上传功能。服务端安装express框架和multer。

npm install express --save
npm install multer --save

服务端启动文件代码：

var express = require('express');
var app = express();
var fileRouter = require('./src/router/fileupload.js')
var bodyParser = require('body-parser');


app.use(express.static('dist'))
app.use(express.static('dist2'))
app.use(bodyParser.json())

app.use('/upload/', fileRouter);
app.get('/', function(req, res) {
  res.redirect('dist/index.html')
});


var server = app.listen(5050, function() {
  var host = server.address().address;
  var port = server.address().port;

  console.log('Example app listening at http://%s:%s', host, port);
});

处理图片上传路由：

var express = require('express');
var router = express.Router();
var fs = require('fs');
var multer = require('multer');


var Storage  = multer.diskStorage({
  destination: function (req, file, cb) {//计算图片存放地址
    cb(null, './imgs')
  },
  filename: function (req, file, cb) {//图片文件名
    console.log(file);
    cb(null, file.originalname)
  }
})
var upload = multer({storage:Storage}).single('file2');//file2表示图片上传文件的key

router.post('/uploadFile',function(req, res, next){
    upload(req, res, function (err) {
        console.log(err)
        if (err) {
            return res.end(err);
        }
        return res.end("File uploaded sucessfully!.");
    });
})
module.exports = router;

至此我们便完成了服务端图片上传的代码。

二、客户端

客户端上传组件主要借助weui的样式，感谢前辈写好的样式哈哈。
代码如下：部分代码可能无用，请自动忽略哈。

<template>
  <div>
    <!-- <v-header></v-header>
    <div>
        <div class="vux-demo">
            <img class="logo" src="../assets/vux_logo.png">
            <h1> </h1>
        </div>
        <group title="cell demo">
            <cell title="Vux" value="Cool" is-link></cell>
        </group>
        <x-button type="primary">Top</x-button>
    </div> -->
    <div class="weui-cells weui-cells_form" id="uploaderCustom">
      <div class="weui-cell">
        <div class="weui-cell__bd">
          <div class="weui-uploader">
            <div class="weui-uploader__hd">
              <p class="weui-uploader__title">图片上传</p>
            </div>
            <div class="weui-uploader__bd">
              <ul class="weui-uploader__files" id="uploaderCustomFiles"></ul>
              <div class="weui-uploader__input-box">
                <input id="uploaderCustomInput" class="weui-uploader__input js_file" type="file">
              </div>
            </div>
          </div>
        </div>
      </div>
    </div>
    <x-button type="primary" class='w80 mt3' action-type='button' @click.native='upload()'>上传</x-button>
  </div>
</template>
<script>
import {
  Toast,
  XButton,
  Group,
  Cell
} from 'vux'
export default {
  components: {
    XButton,
    Group,
    Cell
  },
  data() {
    return {
      // note: changing this line won't causes changes
      // with hot-reload because the reloaded component
      // preserves its current state and we are modifying
      // its initial state.
      msg: 'Hello World!',
      maxSize: 10240000,
      maxCount: 5,
      filesArr: []
    }
  },
  methods: {
    bindEvent() {
      let self = this;
      $("#uploaderCustomInput").on('change', function(event) {
        let files = event.target.files;
        // 如果没有选中文件，直接返回  
        if (files.length === 0) {
          return;
        }
        for (var i = 0; i < files.length; i++) {
          let file = files[i];
          self.filesArr.push(file)
          let reader = new FileReader();
          if (file.size > self.maxSize) {
            self.$alert('图片太大，不允许上传！');
            continue;
          }

          if ($('.weui_uploader_file').length >= self.maxCount) {
            self.$alert(`最多只能上传 ${maxCount} 张图片！`);
            return;
          }
          reader.onload = function(e) {
            var img = new Image();
            img.onload = function() {
              var canvas = document.createElement('canvas');
              var ctx = canvas.getContext('2d');
              var w = img.width;
              var h = img.height;
              // 设置 canvas 的宽度和高度  
              canvas.width = w;
              canvas.height = h;
              ctx.drawImage(img, 0, 0, w, h);
              var base64 = canvas.toDataURL('image/png');

              // 插入到预览区  
              var $preview = $('<li class="weui_uploader_file weui_uploader_status" style="background-image:url(' + base64 + ')"></li>');
              $('#uploaderCustomFiles').append($preview);

            }
            img.src = e.target.result;
          }
          reader.readAsDataURL(file);
        }
      })
    },
    upload() {
      let self = this;
      this.filesArr.map((file) => {
        let param = new FormData();
        param.append('file2', file);
        self.$http.post('/upload/uploadFile', param, {
          'Content-Type': 'multipart/form-data;'
        }).then(function(result) {
          console.log(result)
        })
      })
    }
  },
  mounted() {
    this.bindEvent();
  }
}
</script>
<style>
.vux-demo {
  text-align: center;
}

.logo {
  width: 100px;
  height: 100px
}

.weui-uploader__bd {
  margin-bottom: -4px;
  margin-right: -9px;
  overflow: hidden;
}

.weui-uploader__input-box {
  float: left;
  position: relative;
  margin-right: 9px;
  margin-bottom: 9px;
  width: 77px;
  height: 77px;
  border: 1px solid #d9d9d9;
}

.weui_uploader_file {
  float: left;
  margin-right: 9px;
  margin-bottom: 9px;
  width: 79px;
  height: 79px;
  background: no-repeat center center;
  background-size: cover;
  list-style: none;
}

.weui-uploader__input {
  position: absolute;
  z-index: 1;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}

.weui-uploader__input-box:before {
  width: 2px;
  height: 39.5px;
}

.weui-uploader__input-box:after {
  width: 39.5px;
  height: 2px;
}

.weui-uploader__input-box:after,
.weui-uploader__input-box:before {
  content: " ";
  position: absolute;
  top: 50%;
  left: 50%;
  -webkit-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
  background-color: #d9d9d9;
}
</style>

效果如下：

大致实现了图片上传，还有很多需要优化的地方。后续有时间再分享封装成上传组件的代码。。。