Filter_案例1_登录验证_代码实现与Filter_案例2_过滤敏感词汇_分析

Filter_案例1_登录验证_代码实现

重新打开一个新导航栏：

切换一个浏览器再打开：

package hf.xueqiang.web.filter;

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

/**
 * 完成登录验证的过滤器
 */
@WebFilter("/*")
public class LoginFilter implements Filter {


    public void doFilter(ServletRequest req, ServletResponse response, FilterChain chain) throws ServletException, IOException {
        //0.强制转换
        HttpServletRequest request =(HttpServletRequest) req;

        //1.获取资源请求路径
        String uri = request.getRequestURI();
        //2.判断是否包含登录相关资源路径,要注意排除掉  css/js/图片/验证码等资源
        if(uri.contains("/login.jsp") || uri.contains("/loginServlet") || uri.contains("/css/") || uri.contains("/js/") || uri.contains("/fonts/") || uri.contains("/checkCodeServlet")){
            //包含，用户就是想登录。放行
            chain.doFilter(request,response);
        }else {
            //不包含，需要验证用户是否登录
            //3.从获取session中获取user
            Object user = request.getSession().getAttribute("user");
            if (user !=null){
                //登录了.放行
                chain.doFilter(request,response);
            }else {
                //没有登录。跳转登录页面

                request.setAttribute("login_msg","您尚未登录，请登录");
                request.getRequestDispatcher("/login.jsp").forward(request,response);
            }
        }

        // chain.doFilter(request, response);
    }

    public void init(FilterConfig config) throws ServletException {
    }

    public void destroy() {
    }


}