Question

我目前正在使用登录表单创建一个servlet。当我在表单中输入我的凭据并按下登录按钮时，我会转发到仅限会员的页面，但如果我重新加载页面，我将不再登录。如果我第二次重复登录过程，我将保持登录状态，并且可以自由地留在会员区，直到我自愿退出。

这只发生在Firefox和Chrome中，这个问题在我的IE中没有出现。

这是我的登录类：

 public class Login extends HttpServlet
    {
    private String title;

    public void init() throws ServletException
    {
        title = "Login";
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)  
                        throws ServletException, IOException {  
            response.setContentType("text/html");  
            PrintWriter out=response.getWriter();  

            String username=request.getParameter("username");
            String password=request.getParameter("password");  

            if(password.equals("123") && username.equals("name"))
            {  
                HttpSession session=request.getSession();
                session.setAttribute("name", username);
                loginName = (String) session.getAttribute( "name" );
                out.println("<html>");
                out.println("<head>");
                //...
                out.println("<title>" + title + "</title>");
                out.println("</head>");
                getBody(request, response, out);
                loggedIn(request, response, out);
                out.println("</body>");
                out.println("</html>");
             }  
             else
             {
                out.println("<html>");
                out.println("<head>");

                out.println("<title>" + title + "</title>");
                out.println("</head>");
                getBody(request, response, out);
                notLoggedIn(request, response, out);
                out.println("</body>");
                out.println("</html>");
            }  
            out.close();  
        }

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    {
        response.setContentType("text/html");

        PrintWriter out = response.getWriter();
        out.println("<html>");
        out.println("<head>");
        //...
        out.println("<title>" + title + "</title>");
        out.println("</head>");
        getBody(request, response, out);
        HttpSession session=request.getSession(false);  
        if(session == null)
        {
            //loads the login form
            notLoggedIn(request, response, out);
        }
        else
        {
            //loads the member area
            loggedIn(request, response, out);
        }
        out.println("</body>");
        out.println("</html>");
    }

    public void getBody(HttpServletRequest request, HttpServletResponse response, PrintWriter out)
    {
        out.println("<body ...>");
        //...
    }

    public void notLoggedIn(HttpServletRequest request, HttpServletResponse response, PrintWriter out)
    {
        out.println("<form action='Login' method='post'>");
            out.println("<input type='text' name='username' placeholder='Benutzername' value='' required/>");
            out.println("<input type='password' name='password' placeholder='Passwort' value='' required/>");
            out.println("<input type='submit' value='Login'/>");
        out.println("</form>");
    }

    public void loggedIn(HttpServletRequest request, HttpServletResponse response, PrintWriter out)
    {
        out.println("<form action='Logout' method='get'>");
            out.println("<ul id='links'>");
                out.println("<li><a href='http://www.vipcom/FileSystem'>FileSystem</a></li>");
                out.println("<li><a href='http://www.VIP.com/member2'>Member Area2 Jonah</a></li>");
        out.println("</ul>");
            out.println("<input type='submit' value='Logoff'/>");
        out.println("</form>");
    }
}

Answer 1

我怀疑它在IE中是如何工作的，因为对于每个新请求，您都在创建新会话。如果您不想删除会话对象，则应保留/使用上一个会话对象，如下所示：

//replace the below code
HttpSession session=request.getSession();//every time new session is created.
// with this code at first line of doPost method so that the session will be accessible to your entire method as below:
HttpSession session =null;
if(request.getSession().isNew()){
        session= request.getSession();//new session
}else{
        session= request.getSession(false);//current session
}

而且，您必须从HttpSession session=request.getSession();

中删除

if(password.equals("123") && username.equals("name"))
 {//here

Servlet会话在Firefox中立即被删除

1 个答案: