Example of using Listener to implement global statistics on the website

1. Website global statistical variable class, only define global variables

 1 package com.lt.listener; 2  3 import java.util.Date; 4 import java.util.HashMap; 5 import java.util.Map; 6  7 import javax.servlet.http.HttpSession; 8 /** 9  * 网站全局变量类10  * @author LIUTIE11  *12  */13 public abstract class ApplicationConstants {14     15     /**16      * 用户登录session名称17      */18     public static final String LOGIN_SESSION_NAME = "userInfo";19 20     /**21      * 索引所有的session  
22      * 用于单一登录23      */24     public static Map<string> SESSION_MAP = new HashMap();25     26     /**27      * 当前在线用户数28      */29     public static int CURRENT_LOGIN_COUNT = 0;30     31     /**32      * 历史访客总数33      */34     public static int TOTAL_HISTORY_COUNT = 0;35     36     /**37      * 最高同时在线人数38      */39     public static int MAX_ONLINE_COUNT = 0;40     41     /**42      * 服务器启动时间43      */44     public static Date SERVER_START_DATE = new Date();45     46     /**47      * 最高在线人数时间48      */49     public static Date MAX_ONLINE_COUNT_DATE = new Date();50     51     52     53 }</string>

View Code

2. Implement servletContext monitoring to record server information

 1 package com.lt.listener; 2  3 import java.util.Date; 4  5 import javax.servlet.ServletContextEvent; 6 import javax.servlet.ServletContextListener; 7  8 /** 9  * servletContext监听10  * 记录服务器信息 启动关闭时间等11  * @author LIUTIE12  *13  */14 public class MyContextListener implements ServletContextListener {15 16     /**17      * 服务器启动时被调用18      */19     @Override20     public void contextDestroyed(ServletContextEvent arg0) {21         //记录启动时间22         ApplicationConstants.SERVER_START_DATE = new Date();23     }24 25     /**26      * 服务器关闭时被调用27      */28     @Override29     public void contextInitialized(ServletContextEvent arg0) {30         //保存数据到硬盘31         // TODO Auto-generated method stub32     }33 34 }

View Code

3. Implement HttpSessionListener, HttpSessionAttributeListener monitoring, which is used to record login information, total number of visitors, number of people online, and realize single login, etc.

  1 package com.lt.listener;  2   3 import java.util.Date;  4   5 import javax.servlet.http.HttpSession;  6 import javax.servlet.http.HttpSessionAttributeListener;  7 import javax.servlet.http.HttpSessionBindingEvent;  8 import javax.servlet.http.HttpSessionEvent;  9 import javax.servlet.http.HttpSessionListener; 10  11 /** 12  * session监听 13  * 记录登录信息 访问总人数 在线人数等 14  * 实现单一登录 15  * @author LIUTIE 16  * 17  */ 18 public class MySessionListener implements HttpSessionListener, HttpSessionAttributeListener { 19  20     /** 21      * session创建时被调用 22      */ 23     @Override 24     public void sessionCreated(HttpSessionEvent sessionEvent) { 25         // 获取创建的session 26         HttpSession session = sessionEvent.getSession(); 27         // 添加到map 28         ApplicationConstants.SESSION_MAP.put(session.getId(), session); 29         // 访问总人数++ 30         ApplicationConstants.TOTAL_HISTORY_COUNT++; 31         // 如果map总数大于最高同时在线人数则更新最高在线人数及时间 32         if (ApplicationConstants.MAX_ONLINE_COUNT 

View Code

4. Implement request monitoring to record customer information ip, url, etc.

##

 1 package com.lt.listener; 2  3 import javax.servlet.ServletRequestEvent; 4 import javax.servlet.ServletRequestListener; 5 import javax.servlet.http.HttpServletRequest; 6  7 /** 8  * request监听 用于记录客户信息 ip、url等 9  * 
10  * @author LIUTIE11  *12  */13 public class MyRequestListener implements ServletRequestListener {14 15     /**16      * request销毁时调用17      */18     @Override19     public void requestDestroyed(ServletRequestEvent event) {20         // TODO Auto-generated method stub21 22     }23 24     /**25      * request创建时调用26      */27     @Override28     public void requestInitialized(ServletRequestEvent event) {29         HttpServletRequest request = (HttpServletRequest) event;30         // 客户端ip31         String ip = request.getRemoteAddr();32         // 访问的URL地址33         String url = request.getRequestURI();34         // 只做简单后台打印35         System.out.println("The client ip is " + ip);36         System.out.println("The address url is " + url);37     }38 39 }

View Code

5. Configure a line of listener in web.xml

        <listener><listener-class>com.lt.listener.MyContextListener</listener-class></listener><listener><listener-class>com.lt.listener.MySessionListener</listener-class></listener><listener><listener-class>com.lt.listener.MyRequestListener</listener-class></listener>

View Code

Listener Category:

1. Listener that monitors the creation and destruction of objects:

HttpSessionListener: sessionCreated(HttpSessionEvent sessionEvent), sessionDestroyed(HttpSessionEvent sessionEvent)

ServletRequestListener: requestInitialized(ServletRequestEvent event ), requestDestroyed(ServletRequestEvent event)

ServletContextListener: contextInitialized(ServletContextEvent event), contextDestroyed(ServletContextEvent event)

2. Listener that listens for changes in the properties of the object:

HttpSessionAttributeListener: (Triggered when adding, updating, or removing a session)

attributeAdded(HttpSessionBindingEvent event), attributeReplaced(HttpSessionBindingEvent event), attributeRemoved(HttpSessionBindingEvent event)

ServletContextAttributeListener: (add, update, remove context Triggered when)

attributeAdded(ServletContextAttributeEvent event), attributeReplaced(ServletContextAttributeEvent event), attributeRemoved(ServletContextAttributeEvent event)

ServletRequestAttributeListener: (triggered when adding, updating, or removing a request)

AttributeAdded(ServletRequestAttributeEvent event), attributeReplaced(ServletRequestAttributeEvent event), attributeRemoved(ServletRequestAttributeEvent event)

3. Monitor objects in Session

HttpSessionBindingListener: (Object is put into session, object is removed from session Triggered when)

ValueBound(HttpSessionBindingEvent event), valueUnbound(HttpSessionBindingEvent event)

HttpSessionActivationListener: (Triggered when the object in the session is passivated or the object is reloaded ps: the content in the session The process of saving to the hard disk is called passivation. Passivation requires the implementation of Serializable serialization interface)

sessionWillPassivate(HttpSessionEvent event), sessionDidActivate(HttpSessionEvent event)

The above is the detailed content of Example of using Listener to implement global statistics on the website. For more information, please follow other related articles on the PHP Chinese website!