批量下载文件方法

发表于： 2020年8月27日 2020年8月27日
分类：大文件下载控件(down2)

一、此方法火狐有些版本是不支持的

window.location.href = ‘https://*****.oss-cn-**.aliyuncs.com/*********’;

二、为了解决火狐有些版本不支持,可以改成这种方式

window.location=’https://*****.oss-cn-**.aliyuncs.com/*********’;

三、该方法IE和火狐都可以,url表示要下载的文件路径:

function(url){

try {

var elemIF = document.createElement(“iframe”);

elemIF.src = url;

elemIF.style.display = “none”;

document.body.appendChild(elemIF);

} catch (e) {

alert(“下载异常！”);

}

四、form表单的形式

downloadFile(url){

var form=$(“<form>”);

form.attr(“style”,”display:none”);

form.attr(“target”,””);

form.attr(“method”,”get”);

form.attr(“action”,url);

$(“body”).append(form);

form.submit();//表单提交}

}

五、a标签的方式

function(url,name){

var a = document.createElement(“a”);

a.download = name + “.xls”;

a.href = url;

$(“body”).append(a); // 修复firefox中无法触发click

a.click();

$(a).remove();

}

六、假如后台给的文件流

function (formData, url, name) {

return new Promise((resolve, reject) => {

var xhr = new XMLHttpRequest();

xhr.open(“POST”, url, true); // 也可以使用POST方式，根据接口

xhr.responseType = “blob”; // 返回类型blob

// 定义请求完成的处理函数，请求前也可以增加加载框/禁用下载按钮逻辑

xhr.onload = function () {

// 请求完成

if (this.status === 200) {

// 返回200

var blob = this.response;

var reader = new FileReader();

reader.readAsDataURL(blob); // 转换为base64，可以直接放入a表情href

reader.onload = function (e) {

// 转换完成，创建一个a标签用于下载

var a = document.createElement(“a”);

a.download = name + “.xls”;

a.href = e.target.result;

$(“body”).append(a); // 修复firefox中无法触发click

a.click();

resolve(200)

$(a).remove();

};

}

};

// 发送ajax请求

xhr.send(formData);

})

};

七、download.js

我粘贴一下download的源码

//download.js v4.2, by dandavis; 2008-2016. [CCBY2] see http://danml.com/download.html for tests/usage

// v1 landed a FF+Chrome compat way of downloading strings to local un-named files, upgraded to use a hidden frame and optional mime

// v2 added named files via a[download], msSaveBlob, IE (10+) support, and window.URL support for larger+faster saves than dataURLs

// v3 added dataURL and Blob Input, bind-toggle arity, and legacy dataURL fallback was improved with force-download mime and base64 support. 3.1 improved safari handling.

// v4 adds AMD/UMD, commonJS, and plain browser support

// v4.1 adds url download capability via solo URL argument (same domain/CORS only)

// v4.2 adds semantic variable names, long (over 2MB) dataURL support, and hidden by default temp anchors

// https://github.com/rndme/download

(function (root, factory) {

if (typeof define === ‘function’ && define.amd) {

// AMD. Register as an anonymous module.

define([], factory);

} else if (typeof exports === ‘object’) {

// Node. Does not work with strict CommonJS, but

// only CommonJS-like environments that support module.exports,

// like Node.

module.exports = factory();

} else {

// Browser globals (root is window)

root.download = factory();

}

}(this, function () {

return function download(data, strFileName, strMimeType) {

var self = window, // this script is only for browsers anyway…

defaultMime = “application/octet-stream”, // this default mime also triggers iframe downloads

mimeType = strMimeType || defaultMime,

payload = data,

url = !strFileName && !strMimeType && payload,

anchor = document.createElement(“a”),

toString = function(a){return String(a);},

myBlob = (self.Blob || self.MozBlob || self.WebKitBlob || toString),

fileName = strFileName || “download”,

blob,

reader;

myBlob= myBlob.call ? myBlob.bind(self) : Blob ;

if(String(this)===”true”){ //reverse arguments, allowing download.bind(true, “text/xml”, “export.xml”) to act as a callback

payload=[payload, mimeType];

mimeType=payload[0];

payload=payload[1];

}

if(url && url.length< 2048){ // if no filename and no mime, assume a url was passed as the only argument

fileName = url.split(“/”).pop().split(“?”)[0];

anchor.href = url; // assign href prop to temp anchor

if(anchor.href.indexOf(url) !== -1){ // if the browser determines that it’s a potentially valid url path:

var ajax=new XMLHttpRequest();

ajax.open( “GET”, url, true);

ajax.responseType = ‘blob’;

ajax.οnlοad= function(e){

download(e.target.response, fileName, defaultMime);

};

setTimeout(function(){ ajax.send();}, 0); // allows setting custom ajax headers using the return:

return ajax;

} // end if valid url?

} // end if url?

//go ahead and download dataURLs right away

if(/^data\:[\w+\-]+\/[\w+\-]+[,;]/.test(payload)){

if(payload.length > (1024*1024*1.999) && myBlob !== toString ){

payload=dataUrlToBlob(payload);

mimeType=payload.type || defaultMime;

}else{

return navigator.msSaveBlob ? // IE10 can’t do a[download], only Blobs:

navigator.msSaveBlob(dataUrlToBlob(payload), fileName) :

saver(payload) ; // everyone else can save dataURLs un-processed

}

}//end if dataURL passed?

blob = payload instanceof myBlob ?

payload :

new myBlob([payload], {type: mimeType}) ;

function dataUrlToBlob(strUrl) {

var parts= strUrl.split(/[:;,]/),

type= parts[1],

decoder= parts[2] == “base64” ? atob : decodeURIComponent,

binData= decoder( parts.pop() ),

mx= binData.length,

i= 0,

uiArr= new Uint8Array(mx);

for(i;i<mx;++i) uiArr[i]= binData.charCodeAt(i);

return new myBlob([uiArr], {type: type});

}

function saver(url, winMode){

if (‘download’ in anchor) { //html5 A[download]

anchor.href = url;

anchor.setAttribute(“download”, fileName);

anchor.className = “download-js-link”;

anchor.innerHTML = “downloading…”;

anchor.style.display = “none”;

document.body.appendChild(anchor);

setTimeout(function() {

anchor.click();

document.body.removeChild(anchor);

if(winMode===true){setTimeout(function(){ self.URL.revokeObjectURL(anchor.href);}, 250 );}

}, 66);

return true;

}

// handle non-a[download] safari as best we can:

if(/(Version)\/(\d+)\.(\d+)(?:\.(\d+))?.*Safari\//.test(navigator.userAgent)) {

url=url.replace(/^data:([\w\/\-\+]+)/, defaultMime);

if(!window.open(url)){ // popup blocked, offer direct download:

if(confirm(“Displaying New Document\n\nUse Save As… to download, then click back to return to this page.”)){ location.href=url; }

}

return true;

}

//do iframe dataURL download (old ch+FF):

var f = document.createElement(“iframe”);

document.body.appendChild(f);

if(!winMode){ // force a mime that will download:

url=”data:”+url.replace(/^data:([\w\/\-\+]+)/, defaultMime);

}

f.src=url;

setTimeout(function(){ document.body.removeChild(f); }, 333);

}//end saver

if (navigator.msSaveBlob) { // IE10+ : (has Blob, but not a[download] or URL)

return navigator.msSaveBlob(blob, fileName);

}

if(self.URL){ // simple fast and modern way using Blob and URL:

saver(self.URL.createObjectURL(blob), true);

}else{

// handle non-Blob()+non-URL browsers:

if(typeof blob === “string” || blob.constructor===toString ){

try{

return saver( “data:” + mimeType + “;base64,” + self.btoa(blob) );

}catch(y){

return saver( “data:” + mimeType + “,” + encodeURIComponent(blob) );

}

// Blob but not URL support:

reader=new FileReader();

reader.οnlοad=function(e){

saver(this.result);

};

reader.readAsDataURL(blob);

}

return true;

}; /* end download() */

}));

用法：

download(fileUrl,name,”video/mp4″);

具体更多的用法请参考官网，

注意 download.js第一个参数是数据流，不是像oss那样的文件地址

详细的配置信息可以参考我写的这篇文章：http://blog.ncmem.com/wordpress/2019/08/28/java%e6%89%b9%e9%87%8f%e4%b8%8b%e8%bd%bd/

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