用jQuery下载一个文件。Ajax

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?

当前回答

在Rails中，我是这样做的:

function download_file(file_id) {
  let url       = '/files/' + file_id + '/download_file';
    $.ajax({
    type: 'GET',
    url: url,
    processData: false,
    success: function (data) {
       window.location = url;
    },
    error: function (xhr) {
     console.log(' Error:  >>>> ' + JSON.stringify(xhr));
    }
   });
 }

诀窍在于窗户。位置的部分。控制器的方法如下所示:

# GET /files/{:id}/download_file/
def download_file
    send_file(@file.file,
          :disposition => 'attachment',
          :url_based_filename => false)
end

2017-05-31 19:07:52

其他回答

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。

2019-05-19 18:39:43

让浏览器下载文件的简单方法是像这样发出请求:

 function downloadFile(urlToSend) {
     var req = new XMLHttpRequest();
     req.open("GET", urlToSend, true);
     req.responseType = "blob";
     req.onload = function (event) {
         var blob = req.response;
         var fileName = req.getResponseHeader("fileName") //if you have the fileName header available
         var link=document.createElement('a');
         link.href=window.URL.createObjectURL(blob);
         link.download=fileName;
         link.click();
     };

     req.send();
 }

这将打开浏览器下载弹出。

2017-03-16 09:42:37

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");
    }
}

2020-08-27 08:17:06

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。

2018-01-23 01:10:47

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

2015-04-29 09:03:45

用jQuery下载一个文件。Ajax

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