Calling a method every Day, every Week , every mon

问题:

I need to autoSend reports to my clients at perticular timings like

• every day at 00:01 AM
• every Week at Sunday 00:01 AM
• on day 1 of every month
• on day 1 of every year

For every day i am doing this :

public void contextInitialized(ServletContextEvent arg0) {

        System.out.println("context initiallized");
        System.out.println("Starting timer");

        Calendar calendar = Calendar.getInstance();
        calendar.set(Calendar.HOUR_OF_DAY, 0);
        calendar.set(Calendar.MINUTE, 1);
        calendar.set(Calendar.SECOND, 0);

        Date alarmTime = calendar.getTime();

        _timer = new Timer();
        _timer.schedule(new AlarmTask(), alarmTime);
    }

Here is the class where i perform my everyday task :

public class AlarmTask extends TimerTask {

    public void run() {
        // Do your work here; it's 00:01 AM!         
    }
}

It seems to work fine BUT when i start tomcat at anytime after 00:01 AM Say at 02:30 AM the task is performed as soon as the context is loaded where i need it to be performed on next day...

Is their any problem with my code ?

回答1:

Calendar models the full date so you have scheduled in the past. Timer will respond to that by executing immediately. Increment the day on the Calendar.

回答2:

Why don't you use QuartzSchedular http://quartz-scheduler.org/

回答3:

Have you looked at Quartz ? It could help you schedule your tasks!

回答4:

I guess u will have to do what Marko Topolnik said above https://stackoverflow.com/a/14781326/2040095

but in addition do u also need to invoke the 3 parameters form of method "schedule" for Timer class since you need this report to be send every day and not just one day ?

So something like

_timer.schedule(new AlarmTask(), alarmTime, period );

where period would be a 24 hours for daily reports.

回答5:

If you are doing this in a huge projects I prefer you to go to Quartz Schedular since It has a user interface to handle jobs and create and edit jobs. If it is just a small alarm task that has to executed periodically crate a batch file and add that to chron job to run in specific intervals.

Hope this will help..