如何做session监听，查看是否已登陆，和是否已退出，请高手帮忙。

如何做session监听，查看是否已登陆，和是否已退出如果是已退出给出已退出页面的出错页面。请高手帮忙。

解决方案 »

  1.   

    看看我的BLOG里的这两篇,session监听统计在线人数,filter验证是否登陆权限:
    http://blog.csdn.net/lip009/archive/2006/10/19/1341005.aspx
    http://blog.csdn.net/lip009/archive/2006/10/17/1337730.aspx
      

  2.   

    让用户类实现HttpSessionBindingListener接口，重写valueBound()和valueunBound()两个方法。
      

  3.   

    <%@page contentType="text/html"%>
    <%@page pageEncoding="UTF-8"%> 
     
    <%
            String userSeesion = "";
            String passSession = "";
            String user = "";
            String pass = "";
            boolean isMember=false;
            int errno=0; 
            //提交过来的处理
            if(request.getParameter("user")!=null && request.getParameter("pass")!=null)
            {
                userSeesion = request.getParameter("user");
                passSession = request.getParameter("pass");
                if(!userSeesion.equals("zhoupeng"))
                {//没有用户
                    errno=1;
                }
                else if(!passSession.equals("2002"))
                {//密码错误
                    errno=2;
                } 
                else
                {//已经通过验证的用户
                    errno=3;
                    //注册session
                    //设置时间
                    session.setMaxInactiveInterval(20);
                    //设置session变量
                    session.setAttribute("user",userSeesion);
                    session.setAttribute("pass",passSession);
                } 
            }       
            //是否有session
            String sessionok = (String)session.getAttribute("user");
            String sessionId = "";
            if(sessionok != null)
            {
                isMember = true;
                sessionId = session.getId();
                user = (String)session.getAttribute("user");
                pass = (String)session.getAttribute("pass");
            } 
    %> 
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">   
    <html>
        <head>
            <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> 
            <script type="text/javascript" src="dhtml.inc.js"></script>
            <title>GTNT</title>
        </head>
        <body>
            <form action="" method="post"> 
                <%if(errno == 1){%>
                    <font color="red">没有此用户!</font>
                <%}else if(errno == 2){%>
                    <font color="red">密码错误!</font>
                <%}else if(errno == 3){%>
                    <font color="green">成功登陆!</font> 
                <%}%>  
                <%if(!isMember){%>
                     <center>
                         <table>
                             <tr>
                                 <td align="right">
                                    用户名：
                                 </td>
                                 <td>
                                    <input type="text" name="user" id="userId" value="<%=userSeesion%>" />
                                 </td>
                             </tr>
                             <tr>
                                 <td align="right">
                                    密码：
                                 </td>
                                 <td>
                                    <input type="password" name="pass" id="passId" />
                                 </td>
                             </tr>
                             <tr align="center">
                                 <td>
                                    <input type="submit" name="submit" value="login"   />
                                 </td>
                                 <td>
                                    <input type="reset" value="reset" />
                                 </td>
                             </tr>
                         </table>
                     </center>  
                 <%}else{%> 
                     <br/>
                     <a href="member.jsp"><%=user%></a> 
                     <font color="green">本次登陆生成的sessionId为:<%=sessionId%></font>
                 <%}%>
            </form> 
        </body>
    </html>