一个关于servlet和jsp通信的问题

补充一下，我的servlet程序如下：
package myservlets;
import java.io.*;
import java.text.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;public class LoginCheckServlet extends HttpServlet {
public void doGet(HttpServletRequest request,
                      HttpServletResponse response)
        throws IOException, ServletException
    { HttpSession session = request.getSession();
  response.setContentType("text/html");
      PrintWriter out = response.getWriter();
  String username = request.getParameter("username");
      String password = request.getParameter("password");
      if (username != null && password != null) {
            session.setAttribute(username, password);
        }
  
  if (session.getAttribute(username)==null)
  {
        getServletConfig().getServletContext().getRequestDispatcher("/myjsp/main.jsp").forward(request, response);
  }
  else{
    getServletConfig().getServletContext().getRequestDispatcher("/myjsp/main1.jsp").forward(request, response);
  }
}
     public void doPost(HttpServletRequest request,
                      HttpServletResponse response)
        throws IOException, ServletException
    {
        doGet(request, response);
    }}