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?
这是我所做的，纯javascript和html。没有测试，但这应该在所有浏览器工作。
Javascript函数
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");
});
只使用所有浏览器都支持的组件，不添加其他组件
库。
下面是我的服务器端JAVA Spring控制器代码。
@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();
}
}
}
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。
如何下载一个文件后收到它的AJAX
当文件创建了很长一段时间，你需要显示PRELOADER时，这很方便
例如，当提交一个web表单:
<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>
可选函数被注释掉以简化示例。
不需要在服务器上创建临时文件。
jQuery v2.2.4 OK。旧版本将会有一个错误:
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').
我创建了一个小函数作为解决方案(灵感来自@JohnCulviner插件):
// creates iframe and form in it with hidden field,
// then submit form with provided data
// url - form url
// data - data to form field
// input_name - form hidden input name
function ajax_download(url, data, input_name) {
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 +"'>" +
"<input type=hidden name='" + input_name + "' value='" +
JSON.stringify(data) +"'/></form>" +
"</body></html>";
iframe_doc.open();
iframe_doc.write(iframe_html);
$(iframe_doc).find('form').submit();
}
演示点击事件:
$('#someid').on('click', function() {
ajax_download('/download.action', {'para1': 1, 'para2': 2}, 'dataname');
});
我的方法完全基于jQuery。对我来说，问题是它必须是一个POST-HTTP调用。我希望它是由jQuery单独完成。
解决方案:
$.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.revokeObjectURL(a.href);
...
},
error: errorDialog
});
解释:
我和很多人所做的是在网页上创建一个链接，指出应该下载目标，并将http-request的结果作为目标。之后，我将链接附加到文档，而不是简单地单击链接，然后删除链接。你不再需要iframe了。
神奇之处在于线条
let blob = new Blob([result], { type: "application/octetstream" });
a.href = window.URL.createObjectURL(blob);
The interesting point is that this solution is only working with a "blob". As you can see in other answers, some are simply using a blob but not explaining why and how to create it.
As you can read e.g. in the Mozilla developer documentation you need a file, media ressource or blob for the function "createObjectURL()" to work. The problem is that your http-response might not be any of those.
Therefore the first thing you must do is to convert your response to a blob. This is what the first line does. Then you can use the "createObjectURL" with your newly created blob.
If you than click the link your browser will open a file-save dialog and you can save your data. Obviously it s possible that you cannot define a fixed filename for your file to download. Then you must make your response more complex like in the answer from Luke.
不要忘记释放内存，特别是在处理大文件时。要获得更多的示例和信息，您可以查看JS blob对象的详细信息
