servlet检查登录信息页面

看黑体部分，其它的是session对象，为转向之后的页面记录之用，比如如果session存储的对象值都为guest,则在IndexServlet里就会执行if()里相应的语句。
这是用来在登录成功后显示什么内容，与登录失败显示什么内容相区别。
如登录成功后显示成功后的信息，登录次数，登录失败就显示登录失败的信息与登录框。
package web;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class CheckServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType(“text/html;charset=utf-8″);
PrintWriter out = response.getWriter();
String name=request.getParameter(“username”);
String pwd=request.getParameter(“password”);

if(name!=null&&pwd!=null&&name.equals(“guest”)&&pwd.equals(“guest”)){
HttpSession session=request.getSession();
session.setAttribute(“username”, name);
session.setAttribute(“password”, pwd);
response.sendRedirect(“welcome.jsp”);
return;
}
else{
HttpSession session=request.getSession();
session.setAttribute(“username”, name);
session.setAttribute(“password”, pwd);
response.sendRedirect(“IndexServlet”);
return;
}
}

}