quartz原理分析2----job和trigger的存储

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我是靠谱客的博主超帅月饼，最近开发中收集的这篇文章主要介绍quartz原理分析2----job和trigger的存储，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

对于数据库模式的调度任务，job和trigger需要被存储到数据库中。当服务器再次启动的时候调度任务可以继续执行。

下面分析任务的存储代码。

   public static void main(String[] args) throws SchedulerException {

        SchedulerFactory sf = new StdSchedulerFactory();

        Scheduler scheduler = sf.getScheduler();

        scheduler.pauseJob(JobKey.jobKey("ramJob", "ramGroup"));
        scheduler.pauseTrigger(TriggerKey.triggerKey("ramTrigger", "ramTriggerGroup"));
        scheduler.unscheduleJob(TriggerKey.triggerKey("ramTrigger", "ramTriggerGroup"));
        scheduler.deleteJob(JobKey.jobKey("ramJob", "ramGroup"));

        //job
        JobDetail jb = JobBuilder.newJob(RamJob.class).withDescription("description:ram job")
                .withIdentity("ramJob", "ramGroup").build();

        //trigger
        Trigger trigger = TriggerBuilder.newTrigger().withDescription("ram trigger")
                .withIdentity("ramTrigger", "ramTriggerGroup").startAt(new Date(System.currentTimeMillis() + 3 * 1000))
                .withSchedule(CronScheduleBuilder.cronSchedule("0/2 * * * * ?")).build();

        //包含存储操作
        scheduler.scheduleJob(jb, trigger);

        scheduler.start();
    }

Schedule.scheduleJob方法执行存储操作。

public Date scheduleJob(JobDetail jobDetail, Trigger trigger)
        throws SchedulerException {
        return sched.scheduleJob(jobDetail, trigger);
    }

sched是 QuartzScheduler实例，包含存储job和trigger的方法。

public Date scheduleJob(JobDetail jobDetail,
            Trigger trigger) throws SchedulerException {
        validateState();

        if (jobDetail == null) {
            throw new SchedulerException("JobDetail cannot be null");
        }
        
        if (trigger == null) {
            throw new SchedulerException("Trigger cannot be null");
        }
        
        if (jobDetail.getKey() == null) {
            throw new SchedulerException("Job's key cannot be null");
        }

        if (jobDetail.getJobClass() == null) {
            throw new SchedulerException("Job's class cannot be null");
        }
        
        OperableTrigger trig = (OperableTrigger)trigger;

        if (trigger.getJobKey() == null) {
            trig.setJobKey(jobDetail.getKey());
        } else if (!trigger.getJobKey().equals(jobDetail.getKey())) {
            throw new SchedulerException(
                "Trigger does not reference given job!");
        }

        trig.validate();

        Calendar cal = null;
        if (trigger.getCalendarName() != null) {
            cal = resources.getJobStore().retrieveCalendar(trigger.getCalendarName());
        }
        Date ft = trig.computeFirstFireTime(cal);

        if (ft == null) {
            throw new SchedulerException(
                    "Based on configured schedule, the given trigger '" + trigger.getKey() + "' will never fire.");
        }

        resources.getJobStore().storeJobAndTrigger(jobDetail, trig);
        notifySchedulerListenersJobAdded(jobDetail);
        notifySchedulerThread(trigger.getNextFireTime().getTime());
        notifySchedulerListenersSchduled(trigger);

        return ft;
    }

resources.getJobStore().storeJobAndTrigger(jobDetail, trig);是执行存储的语句。

resources是QuartzSchedulerResources的实例，此类中包含JobStore的实例，JobStore是专门用于存储job和trigger对象的接口。此处使用JobStoreSupport中的方法。JobStoreSupport实现了JobStore接口。

public void storeJobAndTrigger(final JobDetail newJob,
            final OperableTrigger newTrigger) 
        throws JobPersistenceException {
        executeInLock(
            (isLockOnInsert()) ? LOCK_TRIGGER_ACCESS : null,
            new VoidTransactionCallback() {
                public void executeVoid(Connection conn) throws JobPersistenceException {
                    storeJob(conn, newJob, false);
                    storeTrigger(conn, newTrigger, newJob, false,
                            Constants.STATE_WAITING, false, false);
                }
            });
    }

storeJob 和 storeTrigger方法使用sql语句插入任务信息。此处不再列出代码。