一个简单的Timer Service

王朝other·作者佚名  2008-05-31
窄屏简体版  字體: |||超大  

Web-TimeService用于定时调用(触发)应用,EJB2.1也提供了TimerService,但现在有的application server不支持,有的就根本没有用到ejb,所以我写了一个简单的TimerSerivce

Public class TimerService

{

public static final long p = 1000*60*60;

Timer timer = new Timer(false);

TimerSchedule schedule = null;

public TimerService()

{

}

public void start() throws Exception

{

schedule = new TimerSchedule();

schedule.addTimerJob(new SomeTimerJob());

//add other job here

timer.schedule(schedule,0,p);

}

public void stop() throws Exception

{

timer.cancel();

}

}

//包含了多个TimerJob,并每到一定时候取出来看看是否该调用

public class TimerSchedule extends TimerTask

{

private List list = new ArrayList();

public TimerSchedule()

{}

public void addTimerJob(TimerJob job)

{

list.add(job);

}

public void run()

{

Date now = Calendar.getInstance().getTime();

Date next = null;

for(int i=0;i<list.size();i++)

{

TimerJob job = (TimerJob)list.get(i);

next = job.getNextExeDate();

if(isEquals(now,next))

{

job.execute();

}

}

}

/**

* 比较俩个时间相差是否小于TimerService.p(一个周期)

* @param now

* @param next

* @return

*/

private boolean isEquals(Date now,Date next)

{

long time = next.getTime()-now.getTime();

if (time <= TimerService.p && time >= 0)

{

return true;

}

else

{

return false;

}

}

public boolean cancel()

{

return true;

}

}

//该接口描述了如何完成TimerTask,请参考TimerJobExample

interface TimerJob

{

public void execute();

public Date getNextExeDate();

}

/**

* 该例子用于演示如何完成tiemrjob

* 该例子功能是在天天的凌晨一点调用

*/

public class TimerJobExample implements TimerJob

{

Calendar nextDate = null;

public TimerJobExample()

{

nextDate = Calendar.getInstance();

nextDate.add(Calendar.DAY_OF_MONTH,1);

//将设置调用时间是(第二天的)天天凌晨1点

nextDate.set(Calendar.HOUR_OF_DAY,1);

}

public void execute()

{

nextDate.add(Calendar.DAY_OF_MONTH,1);

nextDate.set(Calendar.HOUR_OF_DAY,1);

callFunction();

}

public Date getNextExeDate()

{

return nextDate.getTime();

}

private void callFunction()

{

System.out.println("TimerJobExample call ejb funcation:"+new Date());

}

}

启动Web_TimerService

启动Web-TimerService可以有多种方法,下面列出一个简单的方法,通过jsp来启动,停止TimerService

<%@ page contentType="text/Html; charset=GBK" %>

<%@ page import="com.ted.cfioms.common.alert.*"%>

<%

TimerService service = (TimerService)application.getAttribute("timerService");

boolean isStart = true;

if(service == null)

{

service = new TimerService();

application.setAttribute("timerService",service);

service.start();

}

else

{

service.stop();

isStart = false;

service = null;

}

%>

<html>

<head>

<title>

timerService

</title>

</head>

<body bgcolor="#ffffff">

<h1>

<%=(isStart?

 
 
 
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