Problem with URL parameters& Forms

Question

First off, this is a school assignment so I am not looking for code, just suggestions. I e-mailed my prof, but she hasn't gotten back to me.
I have a nim program, that game where you pick matches up till someone picks up the last match wins. I need to change the program so that it accepts a variable integer to change the starting number of matches. I opted to use a form, but this has gotten me into some trouble. My prof. used url parameters to determine who should go first, the human or the computer.
Basically, I need to submit the variable in order to post the number, but I also need to redirect depending on who goes first.
This is what she did with the URLS:
    [<a href="<%=root%>/StartServlet?first=computer">Computer</a> (that's me!)]
    [<a href="<%=root%>/StartServlet?first=human">Human</a>]My form is just a simple, standard form at the moment:
    <form name="input" action="<%=firstMover%>" method="post">
        <input type="text" name="matches">
        <input type="submit" value="Submit" name="Submit" />
    </form>Variable Retrieval:
        match= request.getParameter("matches");
        matchCount= Integer.parseInt(match);There is a lot of code associated with this program. So if you need more please just ask.
Any suggestions are greatly appreciated as I have no idea...

Answer 1

That might work, but I need to allow the user to choose who goes first, computer or human. I'm not sure if I can do that with a hidden form. (Maybe I am just not seeing it the way you are.) Also, she analyzes whether the person chose computer or human first in the startservlet class. It looks like she parses the URL there and grabs the parameters.
Your suggestion gave me an idea... but I can't get the program to recognize my variable. I don't think I am sending it to the right place.
Form:
<form name="input" action="<%=root%>/StartServlet?" method="post">
        <input type="text" name="matches">
        <select name="firstMove">
            <option value="Computer" checked>Computer</option>
            <option value="Human">Human</option>
        </select>
        <input type="submit" value="Submit" name="Submit" />
    </form>    My request of parameters:
public class StartServlet extends HttpServlet {
    /** Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
    * @param request servlet request
    * @param response servlet response
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        String match= request.getParameter("matches");
        int matchCount= Integer.parseInt(match);
        Nim nim = new Nim(matchCount);
        HttpSession session = request.getSession();
        session.setAttribute("nim", nim);
        String first=request.getParameter("firstMove");
        if ("computer".equals(first)) {
            try {
                nim.machinePlay();
            } catch(NimException e) {}
        }