监听器HttpSessionBindingListener——监听Session属性的绑定、解绑

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/hju22/article/details/87655296

一、项目结构

项目实现：监听对象是否绑定到session

二、用户类

写一个用户类，实现session绑定监听器
User.java

package net.test.bean;

import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionBindingListener;

public class User implements HttpSessionBindingListener {

    private int id;
    private String name;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }


    @Override
    public void valueBound(HttpSessionBindingEvent httpSessionBindingEvent) {
        //绑定
        System.out.println("对象被绑定了");
    }

    @Override
    public void valueUnbound(HttpSessionBindingEvent httpSessionBindingEvent) {
        //解绑
        System.out.println("对象被解绑了");

    }
}

三、servlet测试

写一个servlet，用来测试用户绑定的监听功能
TestUserServlet.java

package net.test.servlet;

import net.test.bean.User;

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 javax.servlet.http.HttpSession;
import java.io.IOException;

@WebServlet(name = "TestUserServlet",urlPatterns = "/testBind")
public class TestUserServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        HttpSession session = request.getSession();
        User user = new User();
        user.setId(1);
        user.setName("小明");
        //绑定对象
        session.setAttribute("user",user);

        //解绑对象
        session.removeAttribute("user");
    }
}

四、部署及运行结果

部署

浏览器中访问：http://localhost:8081/testBind
控制台出现以下结果：