如何 用filter 实现当session失效的时候 跳转到提示页面阿。

Question

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楼主【litingwei8】截止到2008-07-24 17:59:48的历史汇总数据(不包括此帖)：
发帖的总数量:43                       发帖的总分数:1225                     每贴平均分数:28                       
回帖的总数量:20                       得分贴总数量:5                        回帖的得分率:25%                      
结贴的总数量:37                       结贴的总分数:945                      
无满意结贴数:11                       无满意结贴分:530                      
未结的帖子数:6                        未结的总分数:280                      
结贴的百分比:86.05 %               结分的百分比:77.14 %                  
无满意结贴率:29.73 %               无满意结分率:56.08 %                  
楼主加油

Answer 1

   response.sendRedirect(toPageURL);

Answer 2

用过滤器和监听器一起使用：  
  -------------------web.xml配置：  
          <filter>  
                  <filter-name>mainfilter</filter-name>  
                  <filter-class>com.chance.MainFilter</filter-class>  
          </filter>  
          <filter-mapping>  
                  <filter-name>mainfilter</filter-name>  
                  <url-pattern>*</url-pattern>  
          </filter-mapping>  
  ------------------MainFilter.java--------------------------  
  package   com.chance;  
  import   javax.servlet.http.HttpServletRequest;  
  import   javax.servlet.http.HttpServletResponse;  
  import   javax.servlet.*;  
  import   java.io.IOException;  
   
  public   class   MainFilter   implements   Filter{  
          public   void   init(FilterConfig   filterConfig)throws   ServletException{  
                  //  
          }  
   
          public   void   doFilter(ServletRequest   request,  
                                                    ServletResponse   response,FilterChain   chain)throws   ServletException,   IOException{  
                  HttpServletRequest   req   =   (HttpServletRequest)request;  
                  HttpServletResponse   res   =   (HttpServletResponse)response;  
                  boolean   isValid=true;  
                  ///////check   attribute  
                  isValid=req.getSession().getAttribute("name")==null;  
                  if(isValid){  
                          req.getSession().getServletContext()  
                                          .getRequestDispatcher("/login.jsp").forward(req,   res);  
                  }else  
                          chain.doFilter(request,response);  
          }  
   
          public   void   destroy(){}  
  }

Answer 3

if (request.getSession(false) == null) {
    response.sendRedirect("你的提示页");
} else {
    chain.doFilter(request, response);
}

Answer 4

if(session过期)
{
跳
}

Answer 5

 response.sendRedirect(toPageURL); 
right.........

Answer 6

<!-- 用户登录过滤器开始 -->
 <filter>
  <filter-name>checkLoginFilter</filter-name>
  <filter-class>CheckLoginFilter</filter-class>
  <init-param>
  <param-name>checkSessionKey</param-name>
  <param-value>LoginUser</param-value>
  </init-param>
  <init-param>
  <param-name>redirectURL</param-name>
  <param-value>/login.jsf</param-value>
  </init-param>
  <init-param>
  <param-name>notCheckURLList</param-name>
  <param-value>/login.jsf</param-value>
  </init-param>
 </filter>
 <filter-mapping>
  <filter-name>checkLoginFilter</filter-name>
  <url-pattern>*.jsf</url-pattern>
 </filter-mapping>
 
 <!-- 用户登录过滤器结束 -->在web.xml里面加上filterCheckLoginFilter.java/**
 * 用于检测用户是否登陆的过滤器，如果未登录，则重定向到指的登录页面<p>
 * 配置参数<p>
 * checkSessionKey 需检查的在 Session 中保存的关键字<br/>
 * redirectURL 如果用户未登录，则重定向到指定的页面，URL不包括 ContextPath<br/>
 * notCheckURLList 不做检查的URL列表，以分号分开，并且 URL 中不包括 ContextPath<br/>
 */
public class CheckLoginFilter implements Filter
{
    protected FilterConfig filterConfig = null;
    private String redirectURL = null;
    private List<String> notCheckURLList = new ArrayList<String>();
    private String sessionKey = null;    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException{
    
     HttpServletRequest request = (HttpServletRequest) servletRequest;
     HttpServletResponse response = (HttpServletResponse) servletResponse;
     HttpSession session = request.getSession();
     response.setHeader("Cache-Control","no-cache");
     response.setHeader("Pragma","no-cache");
     response.setDateHeader ("Expires", -1);
     if(sessionKey == null){
     filterChain.doFilter(request, response);
     return;
     }
     if((!checkRequestURIIntNotFilterList(request)) && session.getAttribute(sessionKey) == null){
     response.sendRedirect(request.getContextPath() + redirectURL);
     return;
     }
     filterChain.doFilter(servletRequest, servletResponse);
    }    public void destroy(){
     notCheckURLList.clear();
    }    private boolean checkRequestURIIntNotFilterList(HttpServletRequest request){
     String uri = request.getServletPath() + (request.getPathInfo() == null ? "" : request.getPathInfo());
     return notCheckURLList.contains(uri);
    }    public void init(FilterConfig filterConfig) throws ServletException{
     this.filterConfig = filterConfig;
     redirectURL = filterConfig.getInitParameter("redirectURL");
     sessionKey = filterConfig.getInitParameter("checkSessionKey");     String notCheckURLListStr = filterConfig.getInitParameter("notCheckURLList");     if(notCheckURLListStr != null){
     StringTokenizer st = new StringTokenizer(notCheckURLListStr, ";");
     notCheckURLList.clear();
     while(st.hasMoreTokens()){
     notCheckURLList.add(st.nextToken());
     }
     }
    }
}

Answer 7

大概思路是 建一个filter  过滤除登陆页面的其他所有页面  在filter 里取到session 判断里面是否有值 如果有 则正常跳转  否则跳转到登陆页或你需要的指定页面即可~代码楼上都给出了