JavaWeb項目設置Session失效時長，失效後自動跳轉頁面

一、在項目的web.xml文件中設置session失效時間，並添加過濾器java

<!-- 配置session30分鐘後過時 -->
 <session-config>
 　　<session-timeout>30</session-timeout>
 </session-config>  

<!-- 配置過濾器，filter-class路徑爲所編寫的過濾器類的路徑 -->  
  <filter>  
     <filter-name>loginFilter</filter-name>  
     <filter-class>com.sale.filter.LoginFilter</filter-class>  
  </filter>  
  <filter-mapping>  
     <filter-name>loginFilter</filter-name>  
     <url-pattern>*.action</url-pattern>  
  </filter-mapping>

二、過濾器類web

package com.sale.filter; import java.io.IOException; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; /**
 * 過濾器類
 * @author Saffi
 * @date 2018年1月31日
 */

public class LoginFilter implements Filter { @Override public void destroy() { 
 } @Override public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException { HttpServletRequest httpReq=(HttpServletRequest)req; HttpServletResponse httpRes=(HttpServletResponse)res; HttpSession httpSession=httpReq.getSession(); String path = httpReq.getRequestURI();    //當前請求相對url
        String loginUrl = httpReq.getContextPath()+ "/loginout.action";    //登陸界面url
        String initUrl = httpReq.getContextPath()+   "loginInit.action";    //初始化界面url
        String userName = (String)httpSession.getAttribute("currentUsername");    //在session中獲取當前用戶名 // 登錄頁面、初始化頁面均無需過濾
        if(loginUrl.equals(path) || initUrl.equals(path)) { chain.doFilter(req, res); return; } if(userName==null){ httpRes.sendRedirect(loginUrl); return; }else{ chain.doFilter(req, res); return; } } @Override public void init(FilterConfig arg0) throws ServletException { 
 } }