11_Session域监听器

素颜马尾好姑娘i 2023-09-30 20:07 43阅读 0赞

Session域共有四个监听器接口,分别是

HttpSessionListener

HttpSessionAttributeListener

HttpSessionBindingListener

HttpSessionActivationListener

接下来我们就认识一些每个接口和接口中每个方法的用处

监听器代码

HttpSessionListener

HttpSessionAttributeListener

package com.msb.listener;
    import javax.servlet.annotation.WebListener;
    import javax.servlet.http.HttpSessionAttributeListener;
    import javax.servlet.http.HttpSessionBindingEvent;
    import javax.servlet.http.HttpSessionEvent;
    import javax.servlet.http.HttpSessionListener;
    /**
     * @Author: Ma HaiYang
     * @Description: MircoMessage:Mark_7001
     */
    @WebListener
    public class MySessionListener implements HttpSessionListener , HttpSessionAttributeListener {
        @Override
        public void sessionCreated(HttpSessionEvent se) {
            System.out.println("任何一个Session对象创建");
        }
        @Override
        public void sessionDestroyed(HttpSessionEvent se) {
            System.out.println("任何一个Session对象的销毁");
        }
        @Override
        public void attributeAdded(HttpSessionBindingEvent se) {
            System.out.println("任何一个Session对象中添加了数据");
        }
        @Override
        public void attributeRemoved(HttpSessionBindingEvent se) {
            System.out.println("任何一个Session对象中移除了数据");
        }
        @Override
        public void attributeReplaced(HttpSessionBindingEvent se) {
            System.out.println("任何一个Session对象中修改了数据");
        }
    }

![9466478a920fe914229e55914e0c8301.gif][]

![930772ae96fe0983ec4e6885d31886cb.gif][]

HttpSessionBindingListener

package com.msb.listener;
    import javax.servlet.http.HttpSessionBindingEvent;
    import javax.servlet.http.HttpSessionBindingListener;
    /**
     * @Author: Ma HaiYang
     * @Description: MircoMessage:Mark_7001
     */
    /*
    * 可以监听具体的某个session对象的事件的
    *
    * HttpSessionListener 只要在web.xml中配置或者通过@WebListener注解就可以注册监听所有的Session对象
    * HttpSessionBindingListener 必须要通过setAttribute方法和某个session对象绑定之后,监听单独的某个Session对象
    * */
    public class MySessionBindingListener implements HttpSessionBindingListener {
        // 绑定方法
        /*
        session.setAttribute("mySessionBindingListener",new MySessionBindingListener())
         */
        @Override
        public void valueBound(HttpSessionBindingEvent event) {
            System.out.println("监听器和某个session对象绑定了");
        }
        // 解除绑定方法
        /*
        * 当发生如下情况,会触发该方法的运行
        * 1 session.invalidate(); 让session不可用
        * 2 session到达最大不活动时间,session对象回收 ;
        * 3 session.removeAttribute("mySessionBindingListener");手动解除绑定
        * */
        @Override
        public void valueUnbound(HttpSessionBindingEvent event) {
        }
    }

![12b5efafefacb17147c5ed815f3aae16.gif][]

![57a2739a5353ba78ebbe455f309f4928.gif][]

HttpSessionActivationListener

package com.msb.listener;
    import javax.servlet.annotation.WebListener;
    import javax.servlet.http.HttpSessionActivationListener;
    import javax.servlet.http.HttpSessionEvent;
    /**
     * @Author: Ma HaiYang
     * @Description: MircoMessage:Mark_7001
     */
    
    public class MySessionActivationListener implements HttpSessionActivationListener {
        @Override
        public void sessionWillPassivate(HttpSessionEvent se) {
            System.out.println("session即将钝化");
        }
        @Override
        public void sessionDidActivate(HttpSessionEvent se) {
            System.out.println("session活化完毕");
        }
    }

![fa1c3081cefa9f1d76f8589afac19917.gif][]

![72de3ff2f5f19ec608d7c4467d3cad0b.gif][]

[9466478a920fe914229e55914e0c8301.gif]: https://img-blog.csdnimg.cn/img_convert/9466478a920fe914229e55914e0c8301.gif
[930772ae96fe0983ec4e6885d31886cb.gif]: https://img-blog.csdnimg.cn/img_convert/930772ae96fe0983ec4e6885d31886cb.gif
[12b5efafefacb17147c5ed815f3aae16.gif]: https://img-blog.csdnimg.cn/img_convert/12b5efafefacb17147c5ed815f3aae16.gif
[57a2739a5353ba78ebbe455f309f4928.gif]: https://img-blog.csdnimg.cn/img_convert/57a2739a5353ba78ebbe455f309f4928.gif
[fa1c3081cefa9f1d76f8589afac19917.gif]: https://img-blog.csdnimg.cn/img_convert/fa1c3081cefa9f1d76f8589afac19917.gif
[72de3ff2f5f19ec608d7c4467d3cad0b.gif]: https://img-blog.csdnimg.cn/img_convert/72de3ff2f5f19ec608d7c4467d3cad0b.gif