Shulou(Shulou.com)06/02 Report--

本篇内容主要讲解"前端vue+express怎么实现文件的上传下载"，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习"前端vue+express怎么实现文件的上传下载"吧!

新建server.js

yarn init -yyarn add express nodemon -Dvar express = require("express");const fs = require("fs");var path = require("path");const multer = require("multer"); //指定路径的var app = express();app.use(express.json());app.use(express.urlencoded({ extended: true }));// 前端解决跨域问题app.all("*", (req, res, next) => { res.header("Access-Control-Allow-Origin", "*"); next();});// 访问静态资源app.use(express.static(path.join(__dirname)));// 文件上传app.post("/upload", multer({ dest: "./public" }).any(), (req, res) => { const { fieldname, originalname } = req.files[0]; // 创建一个新路径 const name = fieldname.slice(0, fieldname.indexOf(".")); const newName = "public/" + name + path.parse(originalname).ext; fs.rename(req.files[0].path, newName, function (err) { if (err) { res.send({ code: 0, msg: "上传失败", data: [] }); } else { res.send({ code: 1, msg: "上传成功", data: newName }); } });});// 文件下载app.get('/download', function(req, res) { res.download('./public/test.xls');});// 图片下载app.get('/download/img', function(req, res) { res.download('./public/2.jpg');});let port = 9527;app.listen(port, () => console.log(`端口启动: http://localhost:${port}`));

(1):前端文件上传请求

第一种： form表单

Type 1: Input box

changeHandler(event) { let files = event.target.files[0]; console.log("files",files) let data = new FormData(); data.append(files.name,files); console.log("data",data) axios.post("http://localhost:9527/upload",data,{ headers:{ "Content-Type":"multipart/form-data" } }).then(res =>{ console.log("res",res) }) },

(2): front-end file download

The first type: the backend returns a download link address, and the front-end can be used directly.

The second type: use binary stream file download

handleDownload() { axios({ method: 'get', url: "http://localhost:9527/download", data: { test: "test data" }, responseType: "arraybuffer" // arraybuffer is an interface provided in js to process binary }).then(response => { //Create a Blob instance with returned binary data if(! response) return; let blob = new Blob([response.data], { type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", }) // for .xlsx files //generate file path via URL.createObjectURL let url = window.URL.createObjectURL(blob) console.log("url==========",url) //Create a tag let ele = document.createElement("a") ele.style.display = 'none' //Set href attribute to file path, download attribute to file name ele.href = url ele.download = this.name //add a tag to the page and simulate clicking document.querySelectorAll("body")[0].appendChild(ele) ele.click() //remove a tag ele.remove() }); },

(3)Additional: download of binary stream pictures

//downLoadImg() { axios({ method: 'get', url: `http://localhost:9527/download/img`, responseType: 'arraybuffer', params: { id: 12 } }).then(res => { var src = _'data:image/jpg;base64,' + btoa(new Uint8Array(res.data).reduce((data, byte) => data + String.fromCharCode(byte), '')) // this.srcImg = src //Picture echo var a = document.createElement('a') a.href = src a.download = '2.jpg' a.click() a.remove() }) }

At this point, I believe everyone has a deeper understanding of "how to upload and download files in front-end vue+express," so let's actually operate it! Here is the website, more related content can enter the relevant channels for inquiry, pay attention to us, continue to learn!

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