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Javascript 通过jQuery.Ajax下载一个文件

javascript jquery ajax jsp download

Javascript 通过jQuery.Ajax下载一个文件,javascript,jquery,ajax,jsp,download,Javascript,Jquery,Ajax,Jsp,Download,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</

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>
在Firebug中，我看到数据是通过二进制流来检索的。我想知道如何打开文件下载窗口，用户可以通过该窗口将文件保存到本地？

没有人发布过这篇文章。。。所以我会把它贴出来。它可以帮助某人

您不需要通过Ajax来实现这一点。只用

window.location="download.action?para1=value1...."
2019现代浏览器更新

这是我现在推荐的方法，但有几个注意事项：

  • 需要一个相对现代的浏览器
  • 如果预计文件将非常大，则可能需要执行与原始方法类似的操作（iframe和cookie），因为以下某些操作可能消耗的系统内存至少与正在下载的文件一样大和/或其他有趣的CPU副作用
fetch（'https://jsonplaceholder.typicode.com/todos/1')
.然后（resp=>resp.blob（））
.然后（blob=>{
constURL=window.url.createObjectURL（blob）；
常量a=document.createElement（'a'）；
a、 style.display='none'；
a、 href=url；
//您想要的文件名
a、 下载='todo-1.json'；
文件.正文.附件（a）；
a、 单击（）；
window.URL.revokeObjectURL（URL）；
警报（'您的文件已下载！'）；//或者您知道，有更好的用户体验。。。
})

.catch（（）=>警惕（'oh no！'））1。框架不可知：Servlet将文件作为附件下载


<!-- with JS -->
<a href="javascript:window.location='downloadServlet?param1=value1'">
    download
</a>

<!-- without JS -->
<a href="downloadServlet?param1=value1" >download</a>



<!-- with JS -->
<a href="javascript:window.location='downloadAction.action?param1=value1'">
    download
</a>

<!-- without JS -->
<a href="downloadAction.action?param1=value1" >download</a>


使用Struts2（除非您将操作用作Servlet，例如hack），您不需要直接向响应写入任何内容；只需使用并在struts.xml中配置即可：



应用程序/zip
附件filename=“${filename}”
${fileLength}


3。框架无关（/Struts2 Framework）：Servlet（/Action）在浏览器中打开文件

如果要在浏览器中打开文件，而不是下载文件，则必须将内容配置设置为“内联”，但目标不能是当前窗口位置；您必须以javascript创建的新窗口、页面中的
或使用“discussed”target=“\u blank”动态创建的新窗口为目标：


我创建了一个小功能作为解决方案（灵感来自@JohnCulviner plugin）：


好的，基于ndpu的代码，这里有一个改进的（我认为）版本的ajax\u下载-


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();
}


参数作为正确的post参数发送，就像来自输入一样，而不是像前面的示例那样作为json编码的字符串


警告：小心那些表单上可能存在的变量注入。可能有一种更安全的方法来编码这些变量。或者考虑转义它们。
好的，下面是使用MVC时的工作代码，您可以从控制器获取文件

假设您有字节数组声明和填充，您只需要使用File函数（使用System.Web.Mvc）

然后，在同一控制器中，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);
    }



你可以使用HTML5

注意：返回的文件数据必须是base64编码的，因为无法对二进制数据进行JSON编码

在我的
AJAX
响应中，我有一个如下的数据结构：


{
    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)
    }
}



res.set('Content-Disposition', 'attachment; filename=file.txt');


这意味着我可以通过AJAX执行以下操作来保存文件


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取自，必须按照此函数使用


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});
};



函数base64ToBlob（base64，mimetype，slicesize）{
如果（！window.atob | |！window.Uint8Array）{
//当前浏览器没有atob功能。无法继续
返回null；
}
mimetype=mimetype | |“”；
切片大小=切片大小| | 512；
var bytechars=atob（base64）；
var ByteArray=[]；
对于（变量偏移量=0；偏移量


如果您的服务器正在转储要保存的文件数据，这是很好的。然而，我还没有完全弄清楚如何实现HTML4回退
如果您想使用jQuery文件下载，请注意IE。
您需要重置响应，否则将无法下载


    //The IE will only work if you reset response
    getServletResponse().reset();
    //The jquery.fileDownload needs a cookie be set
    getServletResponse().setHeader("Set-Cookie", "fileDownload=true; path=/");
    //Do the reset of your action create InputStream and return



您的操作可以实现
ServletResponseAware
来访问
getServletResponse（）
向上述答案添加更多内容以下载文件

下面是一些生成字节数组的JavaSpring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);
    }



上面将下载文件
这里是我做的，纯javascript和html。没有测试它，但这应该适用于所有浏览器

Javascript函数

只使用所有浏览器支持的组件，无需额外的
图书馆




这是我的服务器端JavaSpring控制器代码


我面对同样的问题，并成功地解决了它。我的用例是这样的

“将JSON数据发布到服务器并接收excel文件。
该excel文件由服务器创建，并作为响应返回给客户端。在浏览器中将该响应作为具有自定义名称的文件下载“

上面的代码片段只是做了以下工作


    

  • 使用XMLHttpRequest将数组作为JSON发布到服务器
    • 

  • 在将内容提取为blob（二进制）后，我们将创建一个可下载的URL，并将其附加到不可见的“a”链接，然后单击它。我在这里发了一个帖子。相反，你也可以做一个简单的尝试。我们不能通过Ajax下载该文件，必须使用XMLHttpRequest
    • 


在这里，我们需要仔细地在服务器端设置一些东西。我在Python Django HttpResponse中设置了几个标题。你需要做些什么

$('#someid').on('click', function() {
    ajax_download('/download.action', {'para1': 1, 'para2': 2});
});



byte[] bytes = .... insert your bytes in the array
return File(bytes, System.Net.Mime.MediaTypeNames.Application.Octet, "nameoffile.exe");



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);
    }



$.fileDownload(mvcUrl('name of the controller'), {
            httpMethod: 'POST',
            successCallback: function (url) {
            //insert success code

            },
            failCallback: function (html, url) {
            //insert fail code
            }
        });



{
    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)
    }
}



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);
}



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});
};



    //The IE will only work if you reset response
    getServletResponse().reset();
    //The jquery.fileDownload needs a cookie be set
    getServletResponse().setHeader("Set-Cookie", "fileDownload=true; path=/");
    //Do the reset of your action create InputStream and return



@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);
    }



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);



var iframe = document.createElement('iframe');
iframe.id = "IFRAMEID";
iframe.style.display = 'none';
document.body.appendChild(iframe);
iframe.src = 'SERVERURL'+'?' + $.param($scope.filtro);
iframe.addEventListener("load", function () {
     console.log("FILE LOAD DONE.. Download should start now");
});



@RequestMapping(value = "/rootto/my/xlsx", method = RequestMethod.GET)
public void downloadExcelFile(@RequestParam(value = "param1", required = false) String param1,
    HttpServletRequest request, HttpServletResponse response)
            throws ParseException {

    Workbook wb = service.getWorkbook(param1);
    if (wb != null) {
        try {
            String fileName = "myfile_" + sdf.format(new Date());
            response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
            response.setHeader("Content-disposition", "attachment; filename=\"" + fileName + ".xlsx\"");
            wb.write(response.getOutputStream());
            response.getOutputStream().close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    }



function downloadURI(uri, name) 
{
    var link = document.createElement("a");
    link.download = name;
    link.href = uri;
    link.click();
}



$("#my-button").on("click", function(){

// Data to post
data = {
    ids: [1, 2, 3, 4, 5]
};

// Use XMLHttpRequest instead of Jquery $ajax
xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
    var a;
    if (xhttp.readyState === 4 && xhttp.status === 200) {
        // Trick for making downloadable link
        a = document.createElement('a');
        a.href = window.URL.createObjectURL(xhttp.response);
        // Give filename you wish to download
        a.download = "test-file.xls";
        a.style.display = 'none';
        document.body.appendChild(a);
        a.click();
    }
};
// Post data to URL which handles post request
xhttp.open("POST", excelDownloadUrl);
xhttp.setRequestHeader("Content-Type", "application/json");
// You should set responseType as blob for binary responses
xhttp.responseType = 'blob';
xhttp.send(JSON.stringify(data));
});



# In python django code
response = HttpResponse(file_content, content_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")



 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();
 }



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));
    }
   });
 }



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



function expdone()
{
    document.getElementById('exportdiv').style.display='none';
}
function expgo()
{
   document.getElementById('exportdiv').style.display='block';
   document.getElementById('exportif').src='test2.php?arguments=data';
}



<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>



<!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>



window.open('/file.txt', '_blank');



res.set('Content-Disposition', 'attachment; filename=file.txt');


$.post("CalculusPage.php", { calculusFunction: true, ID: 29, data1: "a", data2: "b" },

       function(data, status) 
       {
            if (status == "success") 
            {
                /* 2) In the answer the page that uses the previous calculations is downloaded. For example, this can be a page that prints the results of a table calculated in the ajax call. */
                window.location.href = DownloadPage.php+"?ID="+29;
            }               
       }
);

// For example: in the CalculusPage.php

    if ( !empty($_POST["calculusFunction"]) ) 
    {
        $ID = $_POST["ID"];

        $query = "INSERT INTO ExamplePage (data1, data2) VALUES ('".$_POST["data1"]."', '".$_POST["data2"]."') WHERE id = ".$ID;
        ...
    }

// For example: in the DownloadPage.php

    $ID = $_GET["ID"];

    $sede = "SELECT * FROM ExamplePage WHERE id = ".$ID;
    ...

    $filename="Export_Data.xls";
    header("Content-Type: application/vnd.ms-excel");
    header("Content-Disposition: inline; filename=$filename");

    ...

The HTML Code:-

'<button type="button" id="GetFile">Get File!</button>'


The jQuery Code:-

'$('#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);
        }
    });
});'



<script>
$(function () {
    $('form').submit(function () {
        $('#loader').show();
        $.ajax({
            url: $(this).attr('action'),
            data: $(this).serialize(),
            dataType: 'binary',
            xhrFields: {
                'responseType': 'blob'
            },
            success: function(data, status, xhr) {
                $('#loader').hide();
                // if(data.type.indexOf('text/html') != -1){//If instead of a file you get an error page
                //     var reader = new FileReader();
                //     reader.readAsText(data);
                //     reader.onload = function() {alert(reader.result);};
                //     return;
                // }
                var link = document.createElement('a'),
                    filename = 'file.xlsx';
                // if(xhr.getResponseHeader('Content-Disposition')){//filename 
                //     filename = xhr.getResponseHeader('Content-Disposition');
                //     filename=filename.match(/filename="(.*?)"/)[1];
                //     filename=decodeURIComponent(escape(filename));
                // }
                link.href = URL.createObjectURL(data);
                link.download = filename;
                link.click();
            }
        });
        return false;
    });
});
</script>



Uncaught DOMException: Failed to read the 'responseText' property from 'XMLHttpRequest': The value is only accessible if the object's 'responseType' is '' or 'text' (was 'blob').



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();
}



ajaxPostDownload('/fileController/ExportFile', {
    DownloadToken: 'newDownloadToken',
    Name: $txtName.val(),
    Type: $txtType.val()
});



[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");
    }
}



$.ajax({
    type: "POST",
    url: "/some/webpage",
    headers: {'X-CSRF-TOKEN': csrfToken},
    data: additionalDataToSend,
    dataType: "text",
    success: function(result) {
        let blob = new Blob([result], { type: "application/octetstream" }); 

        let a = document.createElement('a');
        a.href = window.URL.createObjectURL(blob);
        a.download = "test.xml";;
        document.body.appendChild(a);
        a.click();
        document.body.removeChild(a);
        window.URL.removeObjectURL(a.href);
                        
        ...
    },
    error: errorDialog
});



let blob = new Blob([result], { type: "application/octetstream" }); 
a.href = window.URL.createObjectURL(blob);