May I ask what information you want to convey with your "model", and to whom?
UML is a very flexible notation, but at its heart it is stil just boxes and lines which mean whetever you and the reader agree them to mean.
Do you want to show the data flows into and out of your
servlets, JSPs and beans? Do you want to show some sort of system state diagram? Do you want to show client and server timelines? Do you want to show a class inheritance structure? etc. etc.
UML has lots of different drawing styles appropriate to different uses.