servlets HttpServletRequest#login（）在Java中不起作用

Question

j_security_check似乎不足以让我执行登录过程。因此，我没有将表单提交给j_security_check，而是创建了自己的servlet，并以编程方式尝试登录。这是可行的，但我无法重定向到我的受限资源。谁能告诉我有什么问题吗？这是我的servlet的processRequest方法：-

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
            String strUsername = request.getParameter("txtusername");
            String strPassword = request.getParameter("txtpassword");
            if(strUsername == null || strPassword == null || strUsername.equals("") || strPassword.equals(""))
                throw new Exception("Username and/or password missing.");
            request.login(strUsername, strPassword);
            System.out.println("Login succeeded!!");

            if(request.isUserInRole(ROLES.ADMIN.getValue())){//enum
                System.out.println("Found in Admin Role");
                response.sendRedirect("/app/Admin/home.jsf");

            }
            else if (request.isUserInRole(ROLES.GENERAL.getValue()))
                response.sendRedirect("/app/Common/index.jsf");
            else //guard
                throw new Exception("No role for user " + request.getRemoteUser());


        }catch(Exception ex){
            //patch work why there needs to be blogger here?
            System.out.println("Invalid username and/or password!!");
            response.sendRedirect("/app/Common/index.jsf");
        }finally {
            out.close();
        }
    } 

一切正常，我甚至可以看到消息“在管理员角色中找到”，但问题是，即使在验证后，我也无法将请求重定向到其他页面

Answer 1

去掉那些线，它们不属于那里：

    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();

及

        out.close();

如果关闭OutputStream，则无法进行重定向。实际上，您应该在服务器日志中看到IllegalStateException: Response already committed

Answer 2

我不确定，但我认为这个问题是我们讨论的主题

https://glassfish.dev.java.net/issues/show_bug.cgi?id=11340