实现用户登录

<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>



    
    



    用户名: 

    密码: 

    

import java.io.Serializable;

public class User implements Serializable {

    private static final long serialVersionUID = 1L;
    private String username;
    private String password;
    public User(){}

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Collection;
import java.util.linkedHashMap;
import java.util.Map;

public class LoginServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException{
        response.setContentType("text/html;charset=utf-8");
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        PrintWriter pw = response.getWriter();
        if(("itcast").equals(username) && ("123").equals(password)){
            User user = new User();
            user.setUsername(username);
            user.setPassword(password);
            request.getSession().setAttribute("user",user);
            response.sendRedirect("/demo_war_exploded/is");
        }else {
            pw.write("用户名或密码错误，登录失败");
        }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException{
        this.doGet(request,response);
    }
}

import javax.servlet.http.*;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class LogoutServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        request.getSession().removeAttribute("user");
        response.sendRedirect("/demo_war_exploded/is");
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
        this.doGet(request,response);
    }

}

import javax.servlet.http.*;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Collection;

public class IndexServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        response.setContentType("text/html;charset=utf-8");
        //创建或获取保存用户信息的Session对象
        HttpSession session = request.getSession();
        User user = (User) session.getAttribute("user");
        if(user == null){
            response.getWriter().print("您还没有登录,请登录");
        }else {
            response.getWriter().print("您已登录，欢迎您,"+user.getUsername()+"!");
            response.getWriter().print("退出");
        }
        //创建cookie存放Session的标识号
        cookie cookie = new cookie("JSESSIONID",session.getId());
        cookie.setMaxAge(60*30);
        cookie.setPath("/demo");
        response.addcookie(cookie);
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException{
        this.doGet(request,response);
    }
}

    
        fx
        fx
    
    
        fx
        /xfx
    
    
        LoginServlet
        LoginServlet
    
    
        LoginServlet
        /login
    
    
        LogoutServlet
        LogoutServlet
    
    
        LogoutServlet
        /ls
    
    
        IndexServlet
        IndexServlet
    
    
        IndexServlet
        /is