Web前端js下载流文件

前端下载文件大概有以下种：

1）a标签链接下载

<a href="url">点击链接下载</a>

 

2）表单form提交下载

var form = $("<form></form>").attr("action", url).attr("method", "post");
        form.append($("<input></input>").attr("type", "hidden").attr("name", "参数1").attr("value", "值1"));
        form.append($("<input></input>").attr("type", "hidden").attr("name", "参数2").attr("value", "值2"));
        form.appendto('body').submit().remove();
//url为请求地址

 

3）使用xmlhttprequest对象下载

var xhr = new xmlhttprequest();            
        var formdata = new formdata();            
        formdata.append('参数1', "值1");            
        formdata.append('参数2',"值2");            
        xhr.open('post', url, true);           
        xhr.setrequestheader("token", token);     //可以带请求头   
        xhr.responsetype = 'blob'; 
        xhr.onload = function (e) {               
            if (this.status == 200) {                    
                var blob = this.response;
                //var responseheaders = xhr.getallresponseheaders();
                //var contentdisposition = this.getresponseheader("content-disposition");
                //var filename = this.getresponseheader("content-disposition").split('filename=')[1];  
                // 获取文件名，需要在后端响应头暴露("access-control-expose-headers", "content-disposition");

                var filename = "xxxx.xxx";
                if (window.navigator.mssaveoropenblob) {
                    navigator.mssaveblob(blob, filename);
                } else {
                    
                    blob.type = "application/octet-stream";
                    var url = url.createobjecturl(blob);
                    var a = document.createelement('a');
                    a.href = url;
                    a.download = filename;
                    a.click();
                    window.url.revokeobjecturl(url);
                    
                }
            }else if(this.status == 404){
                alert("file does not exist!");
            }else{
                alert("failed to download file! ");
            }
            
        };            
        xhr.send(formdata);