Commons fileupload+servlet+jquery Implementation file upload progress bar

Implementation of file dynamic upload, the general idea is this:

First of all, using the Progresslistener interface of common fileupload to talk about the percentage of file uploads in real time,

Then, implement a servlet that reads the session, using AJAX at the Web end to request this servlet for a certain amount of time.

Finally, display the file upload percentage on the web side and make a progress bar.

1. Realize Progresslistener

Servletfileupload upload = new Servletfileupload (upload_factory);
		Class Uploadprogresslistener implements progresslistener{
			private httpservletrequest request;
			Private DecimalFormat df = new DecimalFormat ("#00.0");
			Uploadprogresslistener (HttpServletRequest request) {
				this.request = Request;
			}
			@Override public
			void Update (Long bytesread, long bytestotal, int items) {
				double percent= (double) bytesread*100 /(double) bytestotal;
				SYSTEM.OUT.PRINTLN (Df.format (percent));
				Request.getsession (). setattribute ("Upload_percentage", Df.format (percent));
			}
		Upload.setprogresslistener (Request) (new Uploadprogresslistener);

2. Implementation of the servlet reading session

HttpSession session = Request.getsession ();
		Object Is_begin = Session.getattribute ("Is_upload_begin");
		if (is_begin==null) return;
		if ("0". Equals (Is_begin.tostring ()) return;
		PrintWriter out = Response.getwriter ();
		Object upload_percentage = Session.getattribute ("Upload_percentage");
		Out.write ("{percentage:") +upload_percentage.tostring () + "'}");
		Out.flush ();

Ajax requests for 3.web-end-time intervals

function Beginupload () {
		$ ("#progress_bar"). Show ();
		SetInterval ("Getuploadmeter ()", 1000);
	}
	function Getuploadmeter () {
		$.post ("Uploadmeter", function (data) {
			var json = eval ("+data+"));
			JQuery ("#progress"). CSS ("width", json.percentage/100*200+ "px");
			JQuery ("#msg"). CSS ("padding", "5px"). html (json.percentage+ "%");}