Java--过滤器LoginFilter实现会话超时跳转登录页面_java filter超时

一、说明

1、网站系统登录，从安全的角度来考虑，登录会话超时，再次页面会退到登录界面。
2、本文配置如何通过过滤器（Filter）实现会话超时（如30分钟）跳转到登录页面，分LoginFilter.java类和web.xml配置两部分。

二、实现代码

过滤器类LoginFilter.java

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;  
/**
 * @author 作者:Justin
 * @version 创建时间：2018年1月25日 上午10:36:23
 * 类说明
 */
 
 
public class LoginFilter implements Filter {  
	 @Override
    public void destroy() {  
        // TODO Auto-generated method stub  
  
    }  
    @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();	//当前请求相对url
        String loginUrl = httpReq.getContextPath()+ "/loginout.action";	//1.登录界面url
        String initUrl = httpReq.getContextPath()+   "/tevo_loginInit.action";	//2.初始化界面url
        String userName = (String)httpSession.getAttribute("currentUsername");	//在session中获取当前用户名
        // 1、登陆页面、初始化页面不过滤
        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 {  
        // TODO Auto-generated method stub  
  
    }  
  
}  

web.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
 
 
  <!-- configure loginFilter -->  
  <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>  
  <!-- configure session timeout 30 minute -->  
  <session-config>  
      <session-timeout>30</session-timeout>  
  </session-config>  
 
</web-app>