Running a Java method at a set time each day

Question

I\'m relatively new to Java and I\'ve pick up a project to work on. However, I\'ve run into a block. I need a method to run at a certain times throughout the day. I\'ve d

Answer 1

One possibility could be to use an external scheduler - depending on desired accuracy. On UNIX use CRON, on Windows use the Windows Scheduler. That nicely isolates timing from doing.

You could use a Timer and create a simple class that checks the time every minute or 5 minutes depending on desired granularity. It would be very lightweight.

Answer 2

I'd strongly suggest, if at all possible, that the best approach would be to invoke your script or Java application using your OS's scheduler: for example, "cron" in *nix, or "task scheduler" in Windows.

Answer 3

try the TimerTask class

for more info check out http://oreilly.com/java/archive/quartz.html

import java.util.Calendar;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;

public class ReportGenerator extends TimerTask {

  public void run() {
    System.out.println("Generating report");
    //TODO generate report
  }

}

class MainApplication {

  public static void main(String[] args) {
    Timer timer = new Timer();
    Calendar date = Calendar.getInstance();
    date.set(
      Calendar.DAY_OF_WEEK,
      Calendar.SUNDAY
    );
    date.set(Calendar.HOUR, 0);
    date.set(Calendar.MINUTE, 0);
    date.set(Calendar.SECOND, 0);
    date.set(Calendar.MILLISECOND, 0);
    // Schedule to run every Sunday in midnight
    timer.schedule(
      new ReportGenerator(),
      date.getTime(),
      1000 * 60 * 60 * 24 * 7
    );
  }//Main method ends
}//MainApplication ends