SpringBoot_配置Filter_拦截强制登陆

package com.Ldh.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
/**
 * WebFilter:将某个类修改成配置类
 * 参数:
 *      filterName : 配置一个name,防止多个filterName重名
 *      urlPatterns :配置需要拦截的路径,  jsp页面路径
 */
@WebFilter(filterName = "MyFilter",urlPatterns = "/main/main.jsp")
public class MyFilter implements Filter {

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
//        获取当前请求
        HttpServletRequest request = (HttpServletRequest) servletRequest;
//        获取session作用域对象
        Object admin = request.getSession().getAttribute("admin");
//        判断作用域对象状态
//        等于 空  即为未登陆 强制跳转至登陆页面
            if (admin==null) {
                servletRequest.getRequestDispatcher("/login/login.jsp").forward(servletRequest,servletResponse);
            }else {
//                放行
                filterChain.doFilter(servletRequest, servletResponse);
            }
    }
}