JavaWeb——Listener

介绍

　　Listener是监听域对象生命周期、域对象属性变更的对象

 

方法

HttpSessionBindingEvent sbe对象
　　sbe.getName() 获取触发事件后session的属性名
　　sbe.getSession() 获取session

 

 public void attributeAdded(HttpSessionBindingEvent sbe) {
      /* This method is called when an attribute 
         is added to a session.
      */
        String name = sbe.getName();
        System.out.println("sessoion的"+name+" 被添加属性"+sbe.getSession().getAttribute(name));
    }

    public void attributeRemoved(HttpSessionBindingEvent sbe) {
      /* This method is called when an attribute
         is removed from a session.
      */
        String name = sbe.getName();
        System.out.println("session的"+name+"被移除");
    }

    public void attributeReplaced(HttpSessionBindingEvent sbe) {
      /* This method is invoked when an attribute
         is replaced in a session.
      */
        String name = sbe.getName();
        System.out.println("session的"+name+"被替代为"+sbe.getSession().getAttribute(name));
    }