Java利用过滤器实现完善登录功能

/**
 * @description: 检查用户是否已经完成登录
 * @author: Jie
 * @date: 2022/8/10 9:48
 **/
@WebFilter(filterName = "loginCheckFilter", urlPatterns = "/*")
@Slf4j
public class LoginCheckFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
       
    }
}

package com.jie.reggjie.filter;
 
import cn.hutool.core.text.AntPathMatcher;
import com.alibaba.fastjson.JSON;
import com.jie.reggjie.common.R;
import lombok.extern.slf4j.Slf4j;
 
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
 
/**
 * @description: 检查用户是否已经完成登录
 * @author: Jie
 * @date: 2022/8/10 9:48
 **/
@WebFilter(filterName = "loginCheckFilter", urlPatterns = "/*")
@Slf4j
public class LoginCheckFilter implements Filter {
 
    /**
     * 路径匹配器，支持通配符
     */
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();
 
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        String requestURI = request.getRequestURI();
        log.info("拦截到请求，{}", requestURI);
 
        //2、判断本次请求是否需要处理
        //定义不需要处理的请求路径
        String[] urls = new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/front/**"
        };
        boolean check = check(urls, requestURI);
 
        //3、如果不需要处理，则直接放行
        if (check) {
            log.info("本次请求{}不需要处理", requestURI);
            filterChain.doFilter(request, response);
            return;
        }
 
        //4、判断登录状态，如果已登录，则直接放行
        if (request.getSession().getAttribute("employee") != null) {
            log.info("用户已登录，用户id为：{}", request.getSession().getAttribute("employee"));
            filterChain.doFilter(request, response);
            return;
        }
        log.info("用户未登录");
        //5、如果未登录则返回未登录结果，通过输出流方式向客户端页面响应数据
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
        return;
    }
 
    public boolean check(String[] urls, String requestURI) {
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestURI);
            if (match) {
                return true;
            }
        }
        return false;
    }
}