用户管理的小demo--登录校检

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在user里面装session

1、 LoginServlet.java

2、LoginFilter.java

3、配置路径

结果：

在user里面装session

1、 LoginServlet.java

package com.by.servlet;import com.by.pojo.User;
import com.by.service.UserService;
import com.by.service.impl.UserServiceImpl;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;/*** 注意：*  1、一次只写一层*  2、复杂的代码先写注释，后写代码*  web层： 接受请求 控制跳转,   并调用service层*/
public class LoginServlet extends HttpServlet {private UserService userService = new UserServiceImpl();@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {try{String username = req.getParameter("username");String password = req.getParameter("password");User user = userService.login(username,password);//控制页面的跳转if(user != null){ //登录成功//在user里面 装session : session 可以设置失效时间--浏览器进行关闭HttpSession session = req.getSession();session.setAttribute("user",user);session.setMaxInactiveInterval(60*30); //30分钟//利用重定向//重定向到selectServlet，在selectServlet查询数据，并把数据传递到main.jspresp.sendRedirect("selectUser");
//                resp.sendRedirect("deleteUser");}else{resp.sendRedirect("login.jsp"); //登录失败 去登录页面}}catch (Exception e){e.printStackTrace();}}
}

2、LoginFilter.java

package com.by.filter;import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;public class LoginFilter implements Filter {@Overridepublic void init(FilterConfig filterConfig) throws ServletException {}@Overridepublic void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {HttpServletRequest request = (HttpServletRequest) req;HttpServletResponse response = (HttpServletResponse) resp;//直接放行: “login.jsp”和“/”String uri = request.getRequestURI();if(uri.contains("login") || uri.endsWith("/")){System.out.println("uri:"+uri+"中包含login或以/结尾 --> 直接放行");//放行chain.doFilter(req,resp);//结束return;}//1、从session获取userObject user = request.getSession().getAttribute("user");//2、获取到user，则放行if(user != null){System.out.println("用户已登录 --> 直接放行");//放行chain.doFilter(req,resp);//结束return;}else{System.out.println("用户未登录 --> 重定向到 login.jsp");//3、没有获取到user，则重定向到login.jspresponse.sendRedirect("login.jsp");}}@Overridepublic void destroy() {}
}