会话管理技术实战(用户登录案例)

在这里插入图片描述

[1].创建一个User类，封装用户名和密码。
[2].提供一个首页面，欢迎用户登录:IndexServlet，提供一个退出的链接。
[3].提供一个登录的Servlet:处理登录请求。
[4].提供一个退出的Servlet:处理退出首页面的功能。

登录界面:login.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
      <form action="/chapter05/LoginServlet" method="post">
  用户名：<input type="text" name="username"><br/>
  密码:  <input type="password" name="password"/><br/>
  <input type="submit" value="提交" id="bt"/>
   </form>
</body>
</html>

User.java:

package cn.itcast.chapter05.example02;
/*
 * alt+shift+a:一次性写多行代码
 */
public class User {
      private String name;
      private String password;
	public User() {	
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
}

LoginServlet.java(login.html表单的数据提交到了这里)

package cn.itcast.chapter05.example02;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * Servlet implementation class LoginServlet
 */
public class LoginServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
		//1.获取用户名和密码
        String name=request.getParameter("username");
        String psw=request.getParameter("password");
    //    System.out.println("username="+name+"password="+psw);
        //2.判断用户名和密码是否正确 用户名是传智播客  密码是123，就认为是正确的
        if("传智播客".equals(name)&&"123".equals(psw)) {
           //这里本应查数据库，代码量会更大，暂时模拟一下
        	//登陆成功，跳转到主页面,保存用户信息
        	User u=new User();
        	u.setName(name);
        	u.setPassword(psw);
        	HttpSession session=request.getSession();
        	session.setAttribute("key",u);
        	//自己创建cookie，让session使用自己的cookie,不用默认cookie
        	Cookie c=new Cookie("JESSIONID",session.getId());
        	c.setMaxAge(3600*24*7);
        	c.setPath("/chapter05");
        	response.sendRedirect("/chapter05/index");
        }else {
        	//登录失败
        	response.getWriter().print("用户名和密码错误，登陆失败！");
        }
		
		
		
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

IndexServlet.java(登陆成功之后的显示界面)

package cn.itcast.chapter05.example02;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * Servlet implementation class IndexServlet
 */
public class IndexServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//用来欢迎用户登录，并且显示用户信息
		response.setContentType("text/html;charset=utf-8");
		//1.获取用户信息
		HttpSession session=request.getSession();
		User user=(User)session.getAttribute("key");
		//2.判断用户是否存在
		if(user==null) {//用户不存在,也就是用户根本没有登录
			response.sendRedirect("/chapter05/login.html");
		}else {
			String name=user.getName();
			String url="<a href='/chapter05/logOut'>退出</a>";
			response.getWriter().print("欢迎您: "+name+" 登录本网站  "+url);
		}
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}
}

退出界面:LogOutServlet.java(销毁session)

package cn.itcast.chapter05.example02;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * 退出功能
 */
public class LogOutServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      //清空session
		HttpSession session=request.getSession();
		session.removeAttribute("key");
		session.invalidate();	
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}