public void doFilter(ServletRequest request, ServletResponse response,
???FilterChain chain) throws IOException, ServletException {
??HttpServletRequest hreq = (HttpServletRequest)request;
??HttpServletResponse hres = (HttpServletResponse)response;
??String result = "/Kindergarden/starsheaven37/login.jsp";
?
??RequestDispatcher rd = null;
??String errormessage= config.getInitParameter("errormessage");
??HttpSession session = hreq.getSession();?
???if (session.getAttribute("PerName") == null) {
????rd = hreq.getRequestDispatcher(result);
????request.setAttribute("errormessage",errormessage);
????//System.out.println("UserFilter 过滤器中");
????//System.out.println("对不起您还没登陆，请您先登陆！");
????//hres.sendRedirect(result);
????//rd.forward(request, response);

?//如果采取FORWARD或者是sendRedirect的方法，只能跳转到子窗口中
????PrintWriter out = hres.getWriter();
????out.println("<script type='text/javascript'>window.parent.location='"+result+"'</script>");
???}
???else
???{
????chain.doFilter(request, response);
???}
?}