ServletContextListener,ServletRequestListener,HttpSessionListener监听对象的创建与销毁

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ServletContextListener ，监听application 对象。

ServletRequestListener,监听request 对象。

HttpSessionListener，监听session 对象。

下面用一个简单的例子，用这3个监听器来监听3个对象的创建与销毁。

Hello_Listener.java:

package test;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

public class Hello_Listener implements ServletContextListener,ServletRequestListener,HttpSessionListener
{

@Override
public void contextDestroyed(ServletContextEvent arg0) {
System.out.println("ServletContext 对象被销毁"+arg0.getServletContext());
}

@Override
public void contextInitialized(ServletContextEvent arg0) {
System.out.println("ServletContext 对象被创建"+arg0.getServletContext());
}

@Override
public void sessionCreated(HttpSessionEvent arg0) {
System.out.println("HttpSession 对象被创建");
}

@Override
public void sessionDestroyed(HttpSessionEvent arg0)
{
System.out.println("HttpSession 对象被销毁");
}

@Override
public void requestDestroyed(ServletRequestEvent arg0) {
System.out.println("ServletRequse 对象被销毁");
}

@Override
public void requestInitialized(ServletRequestEvent arg0) {
System.out.println("ServletRequse 对象被创建");
}

}

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>Listener</display-name>


<listener>
<listener-class> test.Hello_Listener</listener-class>
</listener>
</web-app>

index.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h4>Index Page</h4>
<a href="test.jsp">test.jsp</a>
</body>
</html>

test.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h4>Test Page
<% session.invalidate(); %>
</body>
</html>

session.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" session="false"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h4>Session Page</h4>
<%
HttpSession session = request.getSession();

//session 的销毁, 关闭浏览器并不代表session 被销毁，还可以通过jsessionid 找到服务器中的session 对象
//1. 过期
//session.setMaxInactiveInterval(5);

//2. 直接销毁
//session.invalidate();
%>
</body>
</html>

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