java quartz scheduler run at specific time

Question

For example, I want to write a Java program to print "Hello World" at each day 12 am, how can I use Quartz scheduler to achieve this?

Trigger trigger = TriggerUtils.makeDailyTrigger(0, 0);
trigger.setName("trigger1");
trigger.setGroup("group1");

Like this? Where should I put print "hello world" method?

Answer 1

You could use an expression to schedule the execution of the job. e.g.:

public static class HelloJob implements Job {
    @Override
    public void execute(JobExecutionContext ctx) throws JobExecutionException {
        System.out.println("Hello World");
    }
}

public static void main(String[] args) throws SchedulerException {
    String exp = "0 0 0 1/1 * ? *";

    SchedulerFactory factory = new StdSchedulerFactory();
    Scheduler scheduler = factory.getScheduler();
    scheduler.start();
    JobDetail job = JobBuilder.newJob(HelloJob.class).build();
    Trigger trigger = TriggerBuilder.newTrigger()
                                    .startNow()
                                    .withSchedule(
                                         CronScheduleBuilder.cronSchedule(exp))
                                    .build();
    scheduler.scheduleJob(job, trigger);
}

See http://www.cronmaker.com/ for build another expression. e.g. 0 0/1 * 1/1 * ? * every minute for to see the output. See also Cron Expressions.

Answer 2

1. Download quartz Jar Put in lib folder build project

2. Create Class (Job) from which you want to schedule task

   import org.apache.log4j.Logger;
   import org.quartz.Job;
   import org.quartz.JobExecutionContext;
   import org.quartz.JobExecutionException;
   
   public class MyJob implements Job  {
       private Logger log = Logger.getLogger(MyJob.class);
       @Override
       public void execute(JobExecutionContext context) throws JobExecutionException {
   
           log.debug("Hi....");
           System.out.println("Corn Executing.....");
   
       }
   }
   

3. Create Class for schedule your task

   import org.quartz.JobBuilder;
   import org.quartz.JobDetail;
   import org.quartz.Scheduler;
   import org.quartz.SchedulerException;
   import org.quartz.SchedulerFactory;
   import org.quartz.SimpleScheduleBuilder;
   import org.quartz.Trigger;
   import org.quartz.TriggerBuilder;
   import org.quartz.impl.StdSchedulerFactory;
   
   public class JobScheduler {
   
       public static void main(String[] args) {
           // TODO Auto-generated method stub
           try {
               JobDetail job = JobBuilder.newJob(MyJob.class).withIdentity("myjob").build();
   
               Trigger trigger = TriggerBuilder.newTrigger().withSchedule(SimpleScheduleBuilder.simpleSchedule().withIntervalInSeconds(30).repeatForever()).build();
   
               SchedulerFactory schFactory = new StdSchedulerFactory();
               Scheduler scheduler = schFactory.getScheduler(); 
               scheduler.start();
               scheduler.scheduleJob(job, trigger);
   
           }catch (SchedulerException e) {
   
               e.printStackTrace();
           }
       }
   }