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?
这是使用MVC时的工作代码，你从控制器中获取文件
假设你有你的字节数组声明和填充，你唯一需要做的是使用文件函数(使用System.Web.Mvc)
byte[] bytes = .... insert your bytes in the array
return File(bytes, System.Net.Mime.MediaTypeNames.Application.Octet, "nameoffile.exe");
然后，在同一个控制器中，添加这两个函数
protected override void OnResultExecuting(ResultExecutingContext context)
{
CheckAndHandleFileResult(context);
base.OnResultExecuting(context);
}
private const string FILE_DOWNLOAD_COOKIE_NAME = "fileDownload";
/// <summary>
/// If the current response is a FileResult (an MVC base class for files) then write a
/// cookie to inform jquery.fileDownload that a successful file download has occured
/// </summary>
/// <param name="context"></param>
private void CheckAndHandleFileResult(ResultExecutingContext context)
{
if (context.Result is FileResult)
//jquery.fileDownload uses this cookie to determine that a file download has completed successfully
Response.SetCookie(new HttpCookie(FILE_DOWNLOAD_COOKIE_NAME, "true") { Path = "/" });
else
//ensure that the cookie is removed in case someone did a file download without using jquery.fileDownload
if (Request.Cookies[FILE_DOWNLOAD_COOKIE_NAME] != null)
Response.Cookies[FILE_DOWNLOAD_COOKIE_NAME].Expires = DateTime.Now.AddYears(-1);
}
然后你将能够调用你的控制器来下载并获得"success"或"failure"回调
$.fileDownload(mvcUrl('name of the controller'), {
httpMethod: 'POST',
successCallback: function (url) {
//insert success code
},
failCallback: function (html, url) {
//insert fail code
}
});
你可以用HTML5
注意:返回的文件数据必须是base64编码的，因为JSON不能编码二进制数据
在我的AJAX响应中，我有一个看起来像这样的数据结构:
{
result: 'OK',
download: {
mimetype: string(mimetype in the form 'major/minor'),
filename: string(the name of the file to download),
data: base64(the binary data as base64 to download)
}
}
这意味着我可以执行以下操作来通过AJAX保存文件
var a = document.createElement('a');
if (window.URL && window.Blob && ('download' in a) && window.atob) {
// Do it the HTML5 compliant way
var blob = base64ToBlob(result.download.data, result.download.mimetype);
var url = window.URL.createObjectURL(blob);
a.href = url;
a.download = result.download.filename;
a.click();
window.URL.revokeObjectURL(url);
}
函数base64ToBlob是从这里取的，必须按照这个函数使用
function base64ToBlob(base64, mimetype, slicesize) {
if (!window.atob || !window.Uint8Array) {
// The current browser doesn't have the atob function. Cannot continue
return null;
}
mimetype = mimetype || '';
slicesize = slicesize || 512;
var bytechars = atob(base64);
var bytearrays = [];
for (var offset = 0; offset < bytechars.length; offset += slicesize) {
var slice = bytechars.slice(offset, offset + slicesize);
var bytenums = new Array(slice.length);
for (var i = 0; i < slice.length; i++) {
bytenums[i] = slice.charCodeAt(i);
}
var bytearray = new Uint8Array(bytenums);
bytearrays[bytearrays.length] = bytearray;
}
return new Blob(bytearrays, {type: mimetype});
};
如果您的服务器正在转储要保存的文件数据，这很好。然而，我还没有完全弄清楚如何实现HTML4的回退
使用窗口。打开https://developer.mozilla.org/en-US/docs/Web/API/Window/open
例如，你可以把这行代码放在点击处理程序中:
window.open('/file.txt', '_blank');
它将打开一个新选项卡(因为'_blank' window-name)，该选项卡将打开URL。
你的服务器端代码也应该是这样的:
res.set('Content-Disposition', 'attachment; filename=file.txt');
通过这种方式，浏览器应该提示用户将文件保存到磁盘，而不仅仅是向他们显示文件。它还会自动关闭刚刚打开的选项卡。
好的，基于ndpu的代码这里有一个改进的(我认为)ajax_download;-
function ajax_download(url, data) {
var $iframe,
iframe_doc,
iframe_html;
if (($iframe = $('#download_iframe')).length === 0) {
$iframe = $("<iframe id='download_iframe'" +
" style='display: none' src='about:blank'></iframe>"
).appendTo("body");
}
iframe_doc = $iframe[0].contentWindow || $iframe[0].contentDocument;
if (iframe_doc.document) {
iframe_doc = iframe_doc.document;
}
iframe_html = "<html><head></head><body><form method='POST' action='" +
url +"'>"
Object.keys(data).forEach(function(key){
iframe_html += "<input type='hidden' name='"+key+"' value='"+data[key]+"'>";
});
iframe_html +="</form></body></html>";
iframe_doc.open();
iframe_doc.write(iframe_html);
$(iframe_doc).find('form').submit();
}
像这样使用这个;-
$('#someid').on('click', function() {
ajax_download('/download.action', {'para1': 1, 'para2': 2});
});
参数被作为适当的post params发送，就像来自一个输入，而不是像前面的例子一样作为一个json编码的字符串。
注意:要警惕在这些表单上可能出现的变量注入。可能有一种更安全的方式来编码这些变量。或者考虑逃离它们。
I found a fix that while it's not actually using ajax it does allow you to use a javascript call to request the download and then get a callback when the download actually starts. I found this helpful if the link runs a server side script that takes a little bit to compose the file before sending it. so you can alert them that it's processing, and then when it does finally send the file remove that processing notification. which is why I wanted to try to load the file via ajax to begin with so that I could have an event happen when the file is requested and another when it actually starts downloading.
js在首页
function expdone()
{
document.getElementById('exportdiv').style.display='none';
}
function expgo()
{
document.getElementById('exportdiv').style.display='block';
document.getElementById('exportif').src='test2.php?arguments=data';
}
iframe
<div id="exportdiv" style="display:none;">
<img src="loader.gif"><br><h1>Generating Report</h1>
<iframe id="exportif" src="" style="width: 1px;height: 1px; border:0px;"></iframe>
</div>
然后是另一个文件:
<!DOCTYPE html>
<html>
<head>
<script>
function expdone()
{
window.parent.expdone();
}
</script>
</head>
<body>
<iframe id="exportif" src="<?php echo "http://10.192.37.211/npdtracker/exportthismonth.php?arguments=".$_GET["arguments"]; ?>"></iframe>
<script>document.getElementById('exportif').onload= expdone;</script>
</body></html>
我认为有一种方法可以使用js读取数据，这样就不需要php了。但我不知道它的手，我正在使用的服务器支持php，所以这对我有用。我想分享一下，也许能帮到别人。
