先来个download.js源码(未修改)
//download.js v4.2, by dandavis; 2008-2016. [CCBY2] see 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// (function(root, factory){if(typeof define ==='function'&& define.amd){// AMD. Register as an anonymous module.define([], factory);}elseif(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(){returnfunctiondownload(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){returnString(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 anchorif(anchor.href.indexOf(url)!==-1){// if the browser determines that it's a potentially valid url path:var ajax=newXMLHttpRequest();
ajax.open("GET", url,true);
ajax.responseType ='blob';
ajax.onload=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 awayif(/^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 instanceofmyBlob?
payload :newmyBlob([payload],{type: mimeType});functiondataUrlToBlob(strUrl){var parts= strUrl.split(/[:;,]/),
type= parts[1],
decoder= parts[2]=="base64"? atob : decodeURIComponent,
binData=decoder( parts.pop()),
mx= binData.length,
i=0,
uiArr=newUint8Array(mx);for(i;i<mx;++i) uiArr[i]= binData.charCodeAt(i);returnnewmyBlob([uiArr],{type: type});}functionsaver(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);returntrue;}// 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;}}returntrue;}//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 saverif(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{returnsaver("data:"+ mimeType +";base64,"+ self.btoa(blob));}catch(y){returnsaver("data:"+ mimeType +","+encodeURIComponent(blob));}}// Blob but not URL support:
reader=newFileReader();
reader.onload=function(e){saver(this.result);};
reader.readAsDataURL(blob);}returntrue;};/* end download() */}));解决办法一：不修改源码
其实不改源码不算是解决办法，即传入参数时不使用中文即可，如果后台返回的文件url带中文，可使用js的encodeURI(string)方法对文件url进行转码 然后传入即可
download(encodeURI(url)) em~这个api 为encodeURI (26个英文字母第8位 i 而不是 第12位 l)
注意： 只有url一个参数时可这样解决，如果传入了第二个参数filename带中文，需要第二种解决办法
解决办法二：修改源码
如在项目中使用修改后的源码，不能直接对依赖中的download.js进行修改，需重新创建个js文件，将修改后的源码写进去，然后放在公共文件夹下，当需要使用时通过相对路径引入即可.
注意: 使用了修改后的源码就不需要download的依赖了，可在package.json中将对应的download依赖删除掉，同时在项目中对该依赖的引用也删除掉(没有依赖了开发工具也会提示找不到的).
实现关键: 避免url被赋予的值中带有中文!!!
下面代码只解决了filename中带有中文的问题，如果url中带有中文可使用encodeURI传参时转码或在源码内转码。
注：看懂部分源码就能写出适合自己的解决办法，这种未经完整测试，不确定是否有bug
直接上代码(注释处即为修改的地方)
exportfunctiondownload(data, strFileName, strMimeType){var self = window,
defaultMime ="application/octet-stream",
mimeType = strMimeType || defaultMime,
payload = data,//避免带中文的文件名赋值给url//url = !strFileName && !strMimeType && payload,
url =!strMimeType && payload,
anchor = document.createElement("a"),toString=function(a){returnString(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"){
payload=[payload, mimeType];
mimeType=payload[0];
payload=payload[1];}if(url && url.length<2048){
fileName = url.split("/").pop().split("?")[0];
anchor.href = url;if(anchor.href.indexOf(url)!==-1){var ajax=newXMLHttpRequest();
ajax.open("GET", url,true);
ajax.responseType ='blob';
ajax.onload=function(e){download(e.target.response, fileName, defaultMime);};setTimeout(function(){ ajax.send();},0);return ajax;}}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 ?
navigator.msSaveBlob(dataUrlToBlob(payload), fileName):saver(payload);}}
blob = payload instanceofmyBlob?
payload :newmyBlob([payload],{type: mimeType});functiondataUrlToBlob(strUrl){var parts= strUrl.split(/[:;,]/),
type= parts[1],
decoder= parts[2]=="base64"? atob : decodeURIComponent,
binData=decoder( parts.pop()),
mx= binData.length,
i=0,
uiArr=newUint8Array(mx);for(i;i<mx;++i) uiArr[i]= binData.charCodeAt(i);returnnewmyBlob([uiArr],{type: type});}functionsaver(url, winMode){if('download'in anchor){
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);returntrue;}if(/(Version)\/(\d+)\.(\d+)(?:\.(\d+))?.*Safari\//.test(navigator.userAgent)){
url=url.replace(/^data:([\w\/\-\+]+)/, defaultMime);if(!window.open(url)){if(window.confirm("Displaying New Document\n\nUse Save As... to download, then click back to return to this page.")){ window.location.href=url;}}returntrue;}var f = document.createElement("iframe");
document.body.appendChild(f);if(!winMode){
url="data:"+url.replace(/^data:([\w\/\-\+]+)/, defaultMime);}
f.src=url;setTimeout(function(){ document.body.removeChild(f);},333);}if(navigator.msSaveBlob){return navigator.msSaveBlob(blob, fileName);}if(self.URL){saver(self.URL.createObjectURL(blob),true);}else{if(typeof blob ==="string"|| blob.constructor===toString ){try{returnsaver("data:"+ mimeType +";base64,"+ self.btoa(blob));}catch(y){returnsaver("data:"+ mimeType +","+encodeURIComponent(blob));}}
reader=newFileReader();
reader.onload=function(e){saver(this.result);};
reader.readAsDataURL(blob);}returntrue;};为何会产生该问题及为何要对中文转码
皆因下面这段代码，该方法通过创建a标签来发送ajax获取到文件内容并递归了download方法，为url赋值为文件内容(url的最后值需要是文件内容而不是文件路径)
在该段代码中 anchor即为创建的a标签(创建过程在修改后的源码第十行左右)，当为a标签赋值href时，a标签的href会被浏览器自动对中文进行转码，所有若url中带有中文，下面的
if判断将永远为false
,也就
不能发送ajax请求获取到文件内容
所以
需要避免url中带有中文
，或者在判断之前将url也进行encodeURI转码。
注：
浏览器的自动转码效果与encodeURI的转码效果一致.
if(url && url.length<2048){
fileName = url.split("/").pop().split("?")[0];
anchor.href = url;if(anchor.href.indexOf(url)!==-1){var ajax=newXMLHttpRequest();
ajax.open("GET", url,true);
ajax.responseType ='blob';
ajax.onload=function(e){download(e.target.response, fileName, defaultMime);};setTimeout(function(){ ajax.send();},0);return ajax;}}
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