监听器[用于监听ServletRequest对象的产生和销毁] 学习笔记

import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;

//监听器[用于监听ServletRequest对象的产生和销毁]
public class MyServletRequestListener implements ServletRequestListener {
	//产生
	public void requestInitialized(ServletRequestEvent sre) {
		System.out.println("requestInitialized()");
	}
	//销毁
	public void requestDestroyed(ServletRequestEvent sre) {
		System.out.println("requestDestroyed()");
	}
}

<listener> <listener-class>cn.itcast.web.listener.MyServletRequestListener</listener-class> </listener>

	>>创建和销毁：ServletContextListener，Web容器部署时产生，Web容器重新部署时销毁原ServletContext对象
            >>属性变化：ServletContextAttributeListner
		application.setAttirbute("name","jack")
		setAttribute("name","liw")
		removeAttribute("name")