一个简单的Timer Service
时间:2010-09-13
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
* 该例子功能是在每天的凌晨一点调用
*/
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）每天凌晨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());
}
}
一个简单的Timer Service(2)
时间:2010-09-13
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?"start ok":"stop ok")%＞
＜/h1＞
＜/body＞
＜/html＞
简单吧，呵呵，我在网上没找到合适的TimerService，所以自己写的，如果大家有类似的代码，可以提出来参考参考，谢谢 |
