session

最新推荐文章于 2022-11-08 08:00:00 发布

csdn099

最新推荐文章于 2022-11-08 08:00:00 发布

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文章标签： session

本文链接：https://blog.youkuaiyun.com/csdn099/article/details/118075913

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session

内存 -->硬盘钝化（持久化）

硬盘–>内存活化（）

1）session对象的四种状态

HttpSessionBindingListener监听session对象的绑定和解绑
a.session.setAttribute("hobby","play basketball");绑定（将对象a 绑定到session中）
b.session.removeAttribute("hobby");解绑
HttpSessionActivationListener监听session对象的钝化和活化
c.钝化
d.活化

2）绑定解绑

package student.listener;

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

public class BeanListener implements HttpSessionBindingListener {
    @Override
    public void valueBound(HttpSessionBindingEvent httpSessionBindingEvent) {
        System.out.println("绑定" + this + ",sessionId:" + httpSessionBindingEvent.getSession().getId());
    }
    //上面的this代表 session.setAttribute("bean",bean);里面的key
    //HttpSessionBindingEvent里面储存着绑定着对象的session对象

    @Override
    public void valueUnbound(HttpSessionBindingEvent httpSessionBindingEvent) {
        //this是解绑的对象
        System.out.println("解绑"+this+"sessionId:"+httpSessionBindingEvent.getSession().getId());
    }
}

<%
    BeanListener bean = new BeanListener();
    //绑定
    session.setAttribute("bean",bean);
    //这里每刷新一次，bean就会被覆盖一次
%>

分析打印结果

绑定student.listener.BeanListener@422dec60,sessionId:4FAC85B830CFF3FACC1CFBD165970E96
绑定student.listener.BeanListener@6f197bd5,sessionId:4FAC85B830CFF3FACC1CFBD165970E96
解绑student.listener.BeanListener@422dec60sessionId:4FAC85B830CFF3FACC1CFBD165970E96
绑定student.listener.BeanListener@fbbc04f,sessionId:4FAC85B830CFF3FACC1CFBD165970E96
解绑student.listener.BeanListener@6f197bd5sessionId:4FAC85B830CFF3FACC1CFBD165970E96