JSP统计在线用户信息

 

 

package org.springframework.web;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.ContextLoaderListener;

import util.ToolKit;

import com.sun.org.apache.bcel.internal.generic.NEW;

/**
 * 在线统计
 * @author 杨伦亮 Jun 5, 2011
 */
public class OnLineUsers extends ContextLoaderListener implements HttpSessionListener {
	/** user */
	public static final String	        User_Name	        = "username";
	public static final String	        User	           = "user";
	/** onLineUsers */
	public static final String	        Application_Users	= "onLineUsers";
	private static Map<String, String>	usersList	     = new HashMap<String, String>();
	private static Log	              log	              = LogFactory.getLog(OnLineUsers.class);
	
	public void sessionCreated(HttpSessionEvent se) {
	}
	
	@SuppressWarnings("unchecked")
	public void sessionDestroyed(HttpSessionEvent se) {
		HttpSession session = se.getSession();
		ServletContext application = session.getServletContext();
		
		// 取得登录的用户名   
		String username = (String) session.getAttribute(User_Name);
		if("".equals(username)){
			log.fatal(new StringBuffer(username).append(ToolKit.getDateByType(" yyyy年MM月dd日 HH:mm:ss ")).append(" 退出系统!"));
		}
		log.info(username +"\t退出系统!");
		// 从在线列表中删除用户名   
		usersList = (Map<String, String>) application.getAttribute(Application_Users);
		if(usersList.containsKey(username)){
			usersList.remove(username);
			application.setAttribute(Application_Users, usersList);
		}else{
			log.info("用户不在在线列表中!"+usersList);
		}
		
	}
	
	private ContextLoader	contextLoader;
	
	/**
	 * Initialize the root web application context.
	 */
	public void contextInitialized(ServletContextEvent event) {
		this.contextLoader = createContextLoader();
		this.contextLoader.initWebApplicationContext(event.getServletContext());
	}
	
	/**
	 * Create the ContextLoader to use. Can be overridden in subclasses.
	 * @return the new ContextLoader
	 */
	protected ContextLoader createContextLoader() {
		return new ContextLoader();
	}
	
	/**
	 * Return the ContextLoader used by this listener.
	 * @return the current ContextLoader
	 */
	public ContextLoader getContextLoader() {
		return this.contextLoader;
	}
	
	/**
	 * Close the root web application context.
	 */
	public void contextDestroyed(ServletContextEvent event) {
		if(this.contextLoader !=null){
			this.contextLoader.closeWebApplicationContext(event.getServletContext());
		}
	}
}