session扫描器

很经典的一段代码:

list线程安全

线程锁

定时器

package com.gyarmy.servletListener;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Timer;
import java.util.TimerTask;

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

public class Test2 implements HttpSessionListener,ServletContextListener{
	
	private List<HttpSession> list = Collections.synchronizedList(new LinkedList<HttpSession>());
	private Object lock = new Object();
	
	@Override
	public void sessionCreated(HttpSessionEvent se) {
		// TODO Auto-generated method stub
		HttpSession session  = se.getSession();
		
		
		synchronized (lock) {
			list.add(session);
		}
		
		System.out.println("sessionCreated");
	}

	@Override
	public void sessionDestroyed(HttpSessionEvent se) {
		// TODO Auto-generated method stub
		

		System.out.println("sessionDestroyed");
	}

	@Override
	public void contextDestroyed(ServletContextEvent sce) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void contextInitialized(ServletContextEvent sce) {
		// TODO Auto-generated method stub
		
		Timer time = new Timer();
		time.schedule(new MyTimeTask(list,lock), 0, 1000*60*5);
	}

}

class MyTimeTask extends TimerTask{

	private List<HttpSession> list;
	private Object lock;
	
	public MyTimeTask(List<HttpSession> list,Object lock)
	{
		this.list = list;
		this.lock = lock;
	}
	@Override
	public void run() {
		// TODO Auto-generated method stub
		
		synchronized (lock) {
			//删除session
			ListIterator<HttpSession> listIterator = list.listIterator();
			while(listIterator.hasNext())
			{
				HttpSession session = listIterator.next();
				
				if(System.currentTimeMillis()-session.getLastAccessedTime()>1000*60*5)
				{
					//删除这个session
					session.invalidate();
					listIterator.remove();
				}
			}
			
		}

	}
		
}