servlet监听器技术源码

package com.v512.chapter14; import javax.servlet.http.HttpSessionEvent; import javax.servlet.http.HttpSessionListener; public class CountListener implements HttpSessionListener { private static long onlineNumber=0; public void sessionCreated(HttpSessionEvent arg0) { onlineNumber++; } public void sessionDestroyed(HttpSessionEvent arg0) { onlineNumber--; } public static long getOnlineNumber() { return onlineNumber; } }