2020.05.01 Filter过滤器

package com.aojie.web.Filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.io.IOException;

/**
 * @author aojie
 * @fuction
 * @create 2020-05-01 21:26
 */
@WebFilter("/*")
public class LoginFilter implements Filter {
    public void destroy() {
    }

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {

        //强制转换
        HttpServletRequest request=(HttpServletRequest) req;
        //获取请求资源的请求路径
        String requestURI = request.getRequestURI();
        //判断是否是登录相关的资源
        if (requestURI.contains("/login.jsp")||requestURI.contains("/loginServlet")||
                requestURI.contains("/css/")||requestURI.contains("/js/")||
                requestURI.contains("/fonts/")||requestURI.contains("/checkCodeServlet")) {
            //证明用户就是想登录
            chain.doFilter(req, resp);
        }else{
            HttpSession session = request.getSession();
            Object login = session.getAttribute("login");
            if (login != null) {
                chain.doFilter(req, resp);
            }else{
                //没有登录
                request.setAttribute("login_msg","您尚未登录，请先去登录");
                request.getRequestDispatcher("/login.jsp").forward(request,resp);
            }

        }
    }

    public void init(FilterConfig config) throws ServletException {

    }

}