calling a web services from a jsp

i'm new in web services and i just need to find out how you would call a web service from a JSP. been doing a little bit of reading but i dont seem to understand how you go about developing it, i've got the web service URL but dont seem to have a clue where to start or what i need to do

Start with this article, particularly the section on "create a client" and "abstract SOAP altogether" (if the service supports WSDL).