HTTP question

Hi dudes, I've got a new question and I think you`ll get me near to a solution.
The fact is tha I`ve got my aplicattion running on a servlet, and when the client cliks or whatever, I see on the navigation bar, the address of the servlet, and the operation that the client run on the servlet.
I need to codify (?) the result of that operation. But it gots worse, when I check for his identity and password
because I got something like this on the navbigation bar:

http://200.81.20.227/auditoria/servl...plicUsu=345075

I`d like to seed it *** hotmail does:
Eg:

http://200.81.20.227/auditoria/servl...:;CXD:;FN?SEDF)(S=F)(

I must say somenthing, to forward pages, we use one of to methods:

RequestDispatcher rd = servlet.getServletContext().getRequestDispatcher(nextURL);
//I must codify the nextUrl
rd.forward(req, res);

OR:

HttpServletResponse res ...........
....
...
...
res.sendRedirect(nextURL); //I must codify the nextUrl

Thanks so much