Why did I get "FileUploadException: Stream ended unexpectedly" with Apache Commons FileUpload?

Question

What is the reason for encountering this Exception:

org.apache.commons.fileupload.FileUploadException: 
  Processing of multipart/form-data request failed. Stream ended unexpectedly

Answer 1

The main reason is that the underlying socket was closed or reset. The most common reason is that the user closed the browser before the file was fully uploaded. Or the Internet was interrupted during the upload. In any case, the server side code should be able to handle this exception gracefully.

Answer 2

Its been about a year since I dealt with that library, but if I remember correctly, if someone tries to upload a file, then changes the browser URL (clicks a link, opens a bookmark, etc) then you could get that exception.

Answer 3

Some clients do not send multipart properly.

Answer 4

I have been suffering this for a long while in Safari and after some digging found this: http://www.experts-exchange.com/Software/Internet_Email/Web_Browsers/Safari/Q_23147781.html

The answer is to add enctype="multipart/form-data" to your tag attributes.