Session过期后自动跳转到登录页面

https://www.cnblogs.com/sunxun/p/8707380.html

1.配置web.xml

<filter>
    <filter-name>BackEndFilter</filter-name>
    <filter-class>com.sun.BackFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>BackFilter</filter-name>
    <url-pattern>/backend/issues/*
    /backend/repairmen/*
    /backend/payment/*

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2.新建BackFilter类，实现Filter接口。

package com.xyt.backend;
 
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;
 
import com.xyt.common.Logging;
import com.xyt.common.RedisClient;
import com.xyt.jdbc.entity.Admin;
 
/**
 * 后台管理系统登录拦截器
 */
public class BackFilter implements Filter {
 
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        //useless
    }
 
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        HttpSession sess = ((HttpServletRequest)request).getSession();
        String ad = sess.getAttribute("admin");
        if(ad==null ){
            ((HttpServletResponse)response).sendRedirect(((HttpServletRequest)request).getContextPath()+"//login");
        }else{
            chain.doFilter(request, response);
        }
    }
 
    @Override
    public void destroy() {
        //useless
    }
 
}