初识Quartz（二）
这篇文章将是年前的最后一篇，明天就要回家了，在此祝愿OSC的各位coder新年快乐，完事如意！
简单作业：
package quartz_project.example2;
import java.util.Date;
import org.quartz.Job;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.quartz.JobKey;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* 需要在特定的日期或者时间启动，
* 并且期望以一个可能的间隔时间重复执行 n 次的Job
*
* @author caijw
*/
public class SimpleJob implements Job {
private static Logger _log = LoggerFactory.getLogger(SimpleJob.class);
@Override
public void execute(JobExecutionContext ctx) throws JobExecutionException {
JobKey jobKey = ctx.getJobDetail().getKey();
_log.info("SimpleJob says: " + jobKey + " executing at " + new Date());
}
}
注：由于代码较长，本文将按照任务分开解释，第一段代码将做为下列任务的运行环境。
Logger log = LoggerFactory.getLogger(SimpleTriggerExample.class);
log.info("----- Initializing --------");
//第一步我们必须获取一个调度器
SchedulerFactory sf = new StdSchedulerFactory();
Scheduler sched = sf.getScheduler();
log.info("----- Initialization complete -------");
//作业的执行时间（这里需要注意，下面详细说明）
Date startTime = DateBuilder.nextGivenSecondDate(null, 15);
log.info("----- scheduling jobs --------");
注意：Date startTime = DateBuilder.nextGivenSecondDate(null, 15);
每分钟以15秒为单位，在当前时间的在下一个15秒开始。例如：当前时间为18：20：02秒，那么作业将在18：20：15秒执行。
一、在startTime时间点执行job1
JobDetail job = JobBuilder.newJob(SimpleJob.class)
.withIdentity("job1", "group1")
.build();
SimpleTrigger trigger = (SimpleTrigger) TriggerBuilder.newTrigger()
.withIdentity("trigger1", "group1")
.startAt(startTime).build(); //该触发器将在startTime时执行作业
Date ft = sched.scheduleJob(job, trigger);
log.info(job.getKey() + " will run at: " + ft +
" and repeat: " + trigger.getRepeatCount() +
" times, every " + trigger.getRepeatInterval() / 1000 + " seconds");
二、在startTime时间点执行job2
job = JobBuilder.newJob(SimpleJob.class)
.withIdentity("job2", "group1")
.build();
trigger = (SimpleTrigger) TriggerBuilder.newTrigger()
.withIdentity("trigger2", "group1")
.startAt(startTime).build();
ft = sched.scheduleJob(job, trigger);
log.info(job.getKey() + " will run at: " + ft +
" and repeat: " + trigger.getRepeatCount() +
" times, every " + trigger.getRepeatInterval() / 1000 + " seconds");
通过下面的输出结果可以发现：该作业是以多线程并发运行的。
[INFO] 27 一月 09:19:15.000 下午 DefaultQuartzScheduler_Worker-2 [quartz_project.example2.SimpleJob] SimpleJob says: group1.job1 executing at Mon Jan 27 21:19:15 CST 2014 [INFO] 27 一月 09:19:15.000 下午 DefaultQuartzScheduler_Worker-3 [quartz_project.example2.SimpleJob] SimpleJob says: group1.job2 executing at Mon Jan 27 21:19:15 CST 2014
三、在startTime时间点执行job3，以后每隔10s运行一次，重复10次，共运行11次。
job = JobBuilder.newJob(SimpleJob.class)
.withIdentity("job3", "group1")
.build();
trigger = TriggerBuilder.newTrigger()
.withIdentity("trigger3", "group1")
.startAt(startTime)
.withSchedule(SimpleScheduleBuilder.simpleSchedule()
.withIntervalInSeconds(10) //时间间隔10s
.withRepeatCount(10)) //重复次数10次
.forJob(job).build();
ft = sched.scheduleJob(job, trigger);
log.info(job.getKey() + " will run at: " + ft +
" and repeat: " + trigger.getRepeatCount() +
" times, every " + trigger.getRepeatInterval() / 1000 + " seconds");
三、为job3重新绑定trigger，在startTime时间点执行job3，以后每隔10s运行一次，重复2次。
trigger = TriggerBuilder.newTrigger()
.withIdentity("trigger3", "group2") //记得换成group2不然就不唯一了
.startAt(startTime)
.withSchedule(SimpleScheduleBuilder.simpleSchedule()
.withIntervalInSeconds(10)
.withRepeatCount(2))
.forJob(job).build();
ft = sched.scheduleJob(trigger); //注意这里，不可以使用sched.scheduleJob(job, trigger)
log.info(job.getKey() + " will [also] run at: " + ft +
" and repeat: " + trigger.getRepeatCount() +
" times, every " + trigger.getRepeatInterval() / 1000 + " seconds");
四、在当前时间的5分钟后执行job5。
job = JobBuilder.newJob(SimpleJob.class)
.withIdentity("job5", "group1")
.build();
trigger = (SimpleTrigger) TriggerBuilder.newTrigger()
.withIdentity("trigger5", "group1")
.startAt(DateBuilder.futureDate(5, IntervalUnit.MINUTE)) //当前时间的5分钟后
.build();
ft = sched.scheduleJob(job, trigger);
log.info(job.getKey() + " will run at: " + ft +
" and repeat: " + trigger.getRepeatCount() +
" times, every " + trigger.getRepeatInterval() / 1000 + " seconds");
五、在startTime时间点执行job6，以后每隔40s运行一次，无限执行下去。
job = JobBuilder.newJob(SimpleJob.class)
.withIdentity("job6", "group1")
.build();
trigger = TriggerBuilder.newTrigger()
.withIdentity("trigger6", "group1")
.startAt(startTime)
.withSchedule(SimpleScheduleBuilder.simpleSchedule()
.withIntervalInSeconds(40)
.repeatForever()) //无限次
.forJob(job).build();
ft = sched.scheduleJob(job, trigger);
log.info(job.getKey() + " will run at: " + ft +
" and repeat: " + trigger.getRepeatCount() +
" times, every " + trigger.getRepeatInterval() / 1000 + " seconds");
六、所有的作业都被加到了调度器中，但是只有调度器启动作业才会开始执行
log.info("------ starting scheduler -------");
sched.start();//启动调度器
log.info("------ started scheduler -------");
七、在调度器启动后，仍可以添加作业进去：在startTime时间点执行job7，以后每隔5分钟运行一次，执行20次。
job = JobBuilder.newJob(SimpleJob.class)
.withIdentity("job7", "group1")
.build();
trigger = TriggerBuilder.newTrigger()
.withIdentity("trigger7", "group1")
.startAt(startTime)
.withSchedule(SimpleScheduleBuilder.simpleSchedule()
.withIntervalInMinutes(5)
.withRepeatCount(20))
.build();
ft = sched.scheduleJob(job, trigger);
log.info(job.getKey() + " will run at: " + ft +
" and repeat: " + trigger.getRepeatCount() +
" times, every " + trigger.getRepeatInterval() / 1000 + " seconds");
八、作业可以不需要触发器，而是通过手动启动。
job = JobBuilder.newJob(SimpleJob.class)
.withIdentity("job8", "group1")
.storeDurably() //即使没有Trigger关联时，也不需要删除该JobDetail
.build();
sched.addJob(job, true);
log.info("'Manually' triggering job8...");
sched.triggerJob(JobKey.jobKey("job8", "group1"));//通过手动触发，执行作业8
九、重新注册job7，利用线程休眠模拟过了执行时间，效果就是该作业会马上执行一次。
log.info("------- Waiting 30 seconds... --------------");
try {
Thread.sleep(30L * 1000L);
} catch (Exception e) {
log.error(e.getMessage(), e);
}
log.info("---------- rescheduling... -------");
trigger = TriggerBuilder.newTrigger()
.withIdentity("trigger7", "group1")
.startAt(startTime)
.withSchedule(SimpleScheduleBuilder.simpleSchedule()
.withIntervalInMinutes(5)
.withRepeatCount(20))
.build();
ft = sched.rescheduleJob(trigger.getKey(), trigger);
log.info("job7 rescheduled to run at: " + ft);
注意： ft = sched.rescheduleJob(trigger.getKey(), trigger); 表示在sched.start()之后调用，可以在job开始后重新定义trigger，然后重新注册。
十、五分钟后关闭调度器，所以没有执行完的作业将终止。
log.info("------- Waiting five minutes... ------------");
try {
// wait five minutes to show jobs
Thread.sleep(300L * 1000L);
// executing...
} catch (Exception e) {
}
log.info("------- Shutting Down ---------------------");
sched.shutdown(true);
log.info("------- Shutdown Complete -----------------");
十一、查看这段时间内，总执行了多少任务。
SchedulerMetaData metaData = sched.getMetaData();
log.info("Executed " + metaData.getNumberOfJobsExecuted() + " jobs.");