title: how to upload a file using commons file upload streaming api
body: <p>I am following the example provided in the commons file upload site about streaming API. I am stuck trying to figure out how to get the file extension of the uploaded file, how to write the file to a directory and the worst part is where the person who wrote the example comments <code>// Process the input stream...</code> It leaves me wondering if it's something so trivial that I'm the only one  who doesn't know how to. </p>