vue+node实现图片上传及预览的示例方法
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2022-11-09 16:05:06
本文介绍了vue+node实现图片上传及预览的示例方法,分享给大家,具体如下:
先上效果图
上代码
html部分主要是借助了weui的样式...
本文介绍了vue+node实现图片上传及预览的示例方法,分享给大家,具体如下:
先上效果图
上代码
html部分主要是借助了weui的样式
<template> <div> <myheader :title="'发布动态'"> <i class="iconfont icon-fanhui1 left" slot="left" @click="goback"></i> </myheader> <div class="upload"> <div v-if="userinfo._id"> <!--图片上传--> <div class="weui-gallery" id="gallery"> <span class="weui-gallery__img" id="galleryimg"></span> <div class="weui-gallery__opr"> <a href="javascript:" rel="external nofollow" class="weui-gallery__del"> <i class="weui-icon-delete weui-icon_gallery-delete"></i> </a> </div> </div> <div class="weui-cells weui-cells_form"> <div class="weui-cell"> <div class="weui-cell__bd"> <textarea class="weui-textarea" v-model="content" placeholder="你想说啥" rows="3"></textarea> </div> </div> <div class="weui-cell"> <div class="weui-cell__bd"> <div class="weui-uploader"> <div class="weui-uploader__bd"> <ul class="weui-uploader__files" id="uploaderfiles"> <li ref="files" class="weui-uploader__file" v-for="(image,index) in images" :key="index" :style="'backgroundimage:url(' + image +' )'"><span @click="deleteimg(index)" class="x">×</span></li> </ul> <div v-show="images.length < maxcount" class="weui-uploader__input-box"> <input @change="change" id="uploaderinput" class="weui-uploader__input " type="file" multiple accept="image/*"> </div> </div> </div> </div> </div> </div> <a class="weui-btn weui-btn_primary btn-put" style="margin: 20px " @click.prevent.once="put">发送</a> </div> <unlogin v-else> </unlogin> </div> </div> </template>
重点部分在于
<ul class="weui-uploader__files" id="uploaderfiles"> <li ref="files" class="weui-uploader__file" v-for="(image,index) in images" :key="index" :style="'backgroundimage:url(' + image +' )'"><span @click="deleteimg(index)" class="x">×</span></li> </ul> <div v-show="!this.$refs.files||this.$refs.files.length < maxcount" class="weui-uploader__input-box"> <input @change="change" id="uploaderinput" class="weui-uploader__input" type="file" multiple accept="image/*"> </div>
通过@change="change"监听图片的上传,把图片转成base64后(后面会讲怎么转base64)将base64的地址加入到images数组,通过v-for="(image,index) in images"把要上传的图片在页面中显示出来,即达到了预览的效果
js部分
data部分
data() { return { content: '',//分享动态的文字内容 maxsize: 10240000 / 2,//图片的最大大小 maxcount: 8,//最大数量 filesarr: [],//保存要上传图片的数组 images: []//转成base64后的图片的数组 } }
delete方法
deleteimg(index) { this.filesarr.splice(index, 1); this.images.splice(index, 1); }
change方法
change(e) { let files = e.target.files; // 如果没有选中文件,直接返回 if (files.length === 0) { return; } if (this.images.length + files.length > this.maxcount) { toast('最多只能上传' + this.maxcount + '张图片!'); return; } let reader; let file; let images = this.images; for (let i = 0; i < files.length; i++) { file = files[i]; this.filesarr.push(file); reader = new filereader(); if (file.size > self.maxsize) { toast('图片太大,不允许上传!'); continue; } reader.onload = (e) => { let img = new image(); img.onload = function () { let canvas = document.createelement('canvas'); let ctx = canvas.getcontext('2d'); let w = img.width; let 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); let base64 = canvas.todataurl('image/png'); images.push(base64); }; img.src = e.target.result; }; reader.readasdataurl(file); } }
put方法把filesarr中保存的图片通过axios发送到后端,注意要设置headers信息
put() { indicator.open('发布中...'); let self = this; let content = this.content; let param = new formdata(); param.append('content', content); param.append('username', this.userinfo._id); this.filesarr.foreach((file) => { param.append('file2', file); }); self.axios.post('/upload/uploadfile', param, { headers: { "content-type": "application/x-www-form-urlencoded" } }).then(function (result) { console.log(result.data); self.$router.push({path: '/home'}); indicator.close(); toast(result.data.msg) }) }
后端通过multer模块保存传输的图片,再把保存下来的图片发送到阿里云oss(这个可以根据自己的使用情况变化)
let filepath; let filename; let storage = multer.diskstorage({ destination: function (req, file, cb) {//计算图片存放地址 cb(null, './public/img'); }, filename: function (req, file, cb) {//图片文件名 filename = date.now() + '_' + parseint(math.random() * 1000000) + '.png'; filepath = './public/img/' + filename; cb(null, filename) } }); let upload = multer({storage: storage}).any();//file2表示图片上传文件的key router.post('/uploadfile', function (req, res, next) { upload(req, res, function (err) { let content = req.body.content || ''; let username = req.body.username; let imgs = [];//要保存到数据库的图片地址数组 if (err) { return res.end(err); } if (req.files.length === 0) { new pyq({ writer: username, content: content }).save().then((result) => { res.json({ result: result, code: '0', msg: '上传成功' }); }) } /*client.delete('public/img/1.png', function (err) { console.log(err) });*/ let i = 0; req.files.foreach((item, index) => { let filepath = `./public/img/${item.filename}`; put(item.filename,filepath,(result)=>{ imgs.push(result.url); i++; if (i === req.files.length) { //foreach循环是同步的,但上传图片是异步的,所以用一个i去标记图片是否全部上传成功 //这时才把数据保存到数据库 new pyq({ content: content, writer: username, pimg: imgs }).save().then(() => { res.json({ code: '0', msg: '发布成功' }); }) } }) }) }) });
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。
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