How to download file from server using jQuery AJAX and Spring MVC 3

Two options are usually used but neither involves AJAX. And jQuery won't be a great help either.

Option 1: IFrame

Place an invisible IFrame into your page:

<iframe id="downloadFrame" style="display:none"></iframe>

When the download should start (you didn't mention how it is triggered), use Javascript (and possibly jQuery) to set the URL for the IFrame, which is something like /getInvoice/approvalId/123 in your case:

var iframe = document.getElementById("downloadFrame");
iframe .src = "/getInvoice/approvalId/123";

Setting the IFrame URL should trigger the browser to present the download dialog.

Option 2: Navigate to the download URL

The second option is even simpler. Just navigate to the download URL. Once the browser figures out it's a MIME type that cannot be displayed, it will present a download dialog.

So when the download is triggered, execute the following JavaScript code:

window.location.href = "/getInvoice/approvalId/123";

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Note

I'm not sure if all browser will reliably present a download dialog with PDF files. Some browsers might try to display it within the browser itself. The Content-Disposition HTTP header is helpful but no guarantee.

jQuery-ized answer by Codo:

   $('#downloadFrame').remove(); // This shouldn't fail if frame doesn't exist
   $('body').append('<iframe id="downloadFrame" style="display:none"></iframe>');
   $('#downloadFrame').attr('src','/downloadUrlGoesHere');