Java web 之拦截器的小实训

代码部分：

login.jsp

<%--
  Created by IntelliJ IDEA.
  User: ${陈平安}
  Date: 2022/6/1
  Time: 13:21
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    



    姓名

登录

 user.js

function login() {
    var  uname = document.getElementById("uname").valueOf();

    if (uname != null && uname != ""){
        document.getElementById("loguinform").submit();
    }

}

 s01.java

package com.xxx.seervlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;


@WebServlet("/s01")
public class s01 extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String name01 = request.getParameter("username");
        System.out.println(name01);
if ("admin".equals(name01)){
    request.getSession().setAttribute("user01",name01);
    response.sendRedirect("index.jsp");
}else {
    response.sendRedirect("login.jsp");
}
    }
}

 filter01.java

package Filter0x;


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


@WebFilter("/*")
public class filter01 implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest requst = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        String path = requst.getRequestURI();
        System.out.println(path);
        if (path.contains("/login.jsp")) {
            filterChain.doFilter(requst, response);
            return;
        }


        if (path.contains("/js")){
            filterChain.doFilter(requst, response);
            return;
        }
        if (path.contains("/s01")){
            filterChain.doFilter(requst, response);
            return;
        }
        String name02 = (String) requst.getSession().getAttribute("user01");
        if (name02 != null){
            filterChain.doFilter(requst, response);
            return;
        }

        response.sendRedirect("login.jsp");
        return;
    }

    @Override
    public void destroy() {

    }
}

index.jsp

<%--
  Created by IntelliJ IDEA.
  User: ${陈平安}
  Date: 2022/6/1
  Time: 13:23
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    


欢迎${uname}登录

正常访问界面;

异常访问界面：

结果：

跳转回登陆界面；

以上正常访问界面；