我在服务器端有一个Struts2操作用于文件下载。
<action name="download" class="com.xxx.DownAction">
<result name="success" type="stream">
<param name="contentType">text/plain</param>
<param name="inputName">imageStream</param>
<param name="contentDisposition">attachment;filename={fileName}</param>
<param name="bufferSize">1024</param>
</result>
</action>
然而,当我使用jQuery调用动作时:
$.post(
"/download.action",{
para1:value1,
para2:value2
....
},function(data){
console.info(data);
}
);
在Firebug中,我看到数据是用二进制流检索的。我想知道如何打开文件下载窗口,用户可以在本地保存文件?
在上面添加一些东西来下载文件
下面是一些生成字节数组的java spring代码
@RequestMapping(value = "/downloadReport", method = { RequestMethod.POST })
public ResponseEntity<byte[]> downloadReport(
@RequestBody final SomeObejct obj, HttpServletResponse response) throws Exception {
OutputStream out = new ByteArrayOutputStream();
// write something to output stream
HttpHeaders respHeaders = new HttpHeaders();
respHeaders.setContentType(MediaType.APPLICATION_OCTET_STREAM);
respHeaders.add("X-File-Name", name);
ByteArrayOutputStream bos = (ByteArrayOutputStream) out;
return new ResponseEntity<byte[]>(bos.toByteArray(), respHeaders, HttpStatus.CREATED);
}
现在在javascript代码中使用filesver .js,可以下载带有下面代码的文件
var json=angular.toJson("somejsobject");
var url=apiEndPoint+'some url';
var xhr = new XMLHttpRequest();
//headers('X-File-Name')
xhr.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 201) {
var res = this.response;
var fileName=this.getResponseHeader('X-File-Name');
var data = new Blob([res]);
saveAs(data, fileName); //this from FileSaver.js
}
}
xhr.open('POST', url);
xhr.setRequestHeader('Authorization','Bearer ' + token);
xhr.setRequestHeader('Content-Type', 'application/json');
xhr.responseType = 'arraybuffer';
xhr.send(json);
以上将下载文件
这就是它在任何浏览器中都很好(我使用asp.net核心)
function onDownload() {
const api = '@Url.Action("myaction", "mycontroller")';
var form = new FormData(document.getElementById('form1'));
fetch(api, { body: form, method: "POST"})
.then(resp => resp.blob())
.then(blob => {
const url = window.URL.createObjectURL(blob);
$('#linkdownload').attr('download', 'Attachement.zip');
$('#linkdownload').attr("href", url);
$('#linkdownload')
.fadeIn(3000,
function() { });
})
.catch(() => alert('An error occurred'));
}
<button type="button" onclick="onDownload()" class="btn btn-primary btn-sm">Click to Process Files</button>
<a role="button" href="#" style="display: none" class="btn btn-sm btn-secondary" id="linkdownload">Click to download Attachments</a>
<form asp-controller="mycontroller" asp-action="myaction" id="form1"></form>
function onDownload() {
const api = '@Url.Action("myaction", "mycontroller")';
//form1 is your id form, and to get data content of form
var form = new FormData(document.getElementById('form1'));
fetch(api, { body: form, method: "POST"})
.then(resp => resp.blob())
.then(blob => {
const url = window.URL.createObjectURL(blob);
$('#linkdownload').attr('download', 'Attachments.zip');
$('#linkdownload').attr("href", url);
$('#linkdownload')
.fadeIn(3000,
function() {
});
})
.catch(() => alert('An error occurred'));
}
如果服务器在响应中写入文件(包括cookie)
你使用它们来确定文件下载是否开始),简单地创建一个带有值的表单并提交它:
function ajaxPostDownload(url, data) {
var $form;
if (($form = $('#download_form')).length === 0) {
$form = $("<form id='download_form'" + " style='display: none; width: 1px; height: 1px; position: absolute; top: -10000px' method='POST' action='" + url + "'></form>");
$form.appendTo("body");
}
//Clear the form fields
$form.html("");
//Create new form fields
Object.keys(data).forEach(function (key) {
$form.append("<input type='hidden' name='" + key + "' value='" + data[key] + "'>");
});
//Submit the form post
$form.submit();
}
用法:
ajaxPostDownload('/fileController/ExportFile', {
DownloadToken: 'newDownloadToken',
Name: $txtName.val(),
Type: $txtType.val()
});
控制器方法:
[HttpPost]
public FileResult ExportFile(string DownloadToken, string Name, string Type)
{
//Set DownloadToken Cookie.
Response.SetCookie(new HttpCookie("downloadToken", DownloadToken)
{
Expires = DateTime.UtcNow.AddDays(1),
Secure = false
});
using (var output = new MemoryStream())
{
//get File
return File(output.ToArray(), "application/vnd.ms-excel", "NewFile.xls");
}
}
HTML代码:
<button type="button" id="GetFile">Get File!</button>
jQuery代码:
$('#GetFile').on('click', function () {
$.ajax({
url: 'https://s3-us-west-2.amazonaws.com/s.cdpn.io/172905/test.pdf',
method: 'GET',
xhrFields: {
responseType: 'blob'
},
success: function (data) {
var a = document.createElement('a');
var url = window.URL.createObjectURL(data);
a.href = url;
a.download = 'myfile.pdf';
document.body.append(a);
a.click();
a.remove();
window.URL.revokeObjectURL(url);
}
});
});