Getting file path for webservice project

[Steve Simon]

I am using Glassfish, and am attempting to write files to disk from a web application.

Unfortunately the file is written directly to the Glassfish server directory ("C:\...\.netbeans\7.0\config\GF3\domain1")
and not to my project directory (which is where I want it to be saved to).

For Servlets, I got around this problem, using the following method:
String filepath = getServletContext().getRealPath("/");

But for my web service, I cannot use this method, and am struggling to find one which would work.
Does anyone know of a method which might help?

Thanks very much