Java file upload in Servlet using Apache commons FileUpload component (sample code)

This should be a very simple program, but it took me some time to figure out how to use Apache commons FileUpload component. Since nobody will read this, I put it here only for my own reference. Be careful about how to save the uploaded files to server. The HTML code for Form is too simple and can find everywhere, so the following is only the code of doPost method in servlet.

protected void doPost(HttpServletRequest res, HttpServletResponse response)
			throws ServletException, IOException {
 
		// Commons file upload classes are specifically instantiated
		FileItemFactory factory = new DiskFileItemFactory();
 
		ServletFileUpload upload = new ServletFileUpload(factory);
		ServletOutputStream out = null;
 
		try {
			// Parse the incoming HTTP request
			// Commons takes over incoming request at this point
			// Get an iterator for all the data that was sent
			List items = upload.parseRequest(res);
			Iterator iter = items.iterator();
 
			// Set a response content type
			response.setContentType("text/html");
 
			// Setup the output stream for the return XML data
			out = response.getOutputStream();
 
			// Iterate through the incoming request data
			while (iter.hasNext()) {
				// Get the current item in the iteration
				FileItem item = (FileItem) iter.next();
 
				// If the current item is an HTML form field
				if (item.isFormField()) {
					// Return an XML node with the field name and value
					out.println("this is a form data " + item.getFieldName() + "<br>");
 
					// If the current item is file data
				} else {
					// Specify where on disk to write the file
					// Using a servlet init param to specify location on disk
					// Write the file data to disk
					// TODO: Place restrictions on upload data
					File disk = new File("C:\\uploaded_files\\"+item.getName());
					item.write(disk);
 
					// Return an XML node with the file name and size (in bytes)
					//out.println(getServletContext().getRealPath("/WEB_INF"));
					out.println("this is a file with name: " + item.getName());
				}
			}
 
			// Close off the response XML data and stream
 
			out.close();
			// Rudimentary handling of any exceptions
			// TODO: Something useful if an error occurs
		} catch (FileUploadException fue) {
			fue.printStackTrace();
		} catch (IOException ioe) {
			ioe.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}
 
	}

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