解析spring schedule 任务调度

Spring在schedule这块支持JDK Timer、concurrent、quartz三种，这三种任务调度方案在实现机制和调用方法上都不同，但spring通过对其包装，使得基于spring能用统一的配置和编码风格来使用这三种schedule方案。

总得来说这三种schedule都是基于scheduler->trigger->job的基本流程，因此spring通过TimerFactoryBean、ScheduledExecutorFactoryBean和SchedulerFactoryBean分别实现JDK Timer、concurrent和quartz的基本流程。主要逻辑如下代码所示：

TimerFactoryBean

[java]
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public void afterPropertiesSet() {
logger.info("Initializing Timer");
this.timer = createTimer(this.beanName, this.daemon);
// Register specified ScheduledTimerTasks, if necessary.

if (!ObjectUtils.isEmpty(this.scheduledTimerTasks)) {
//注册task和timer registerTasks(this.scheduledTimerTasks, this.timer);

}
}

[c-sharp]
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public void afterPropertiesSet() {
if (logger.isInfoEnabled()) {
logger.info("Initializing ScheduledExecutorService" +
(this.beanName != null ? " '" + this.beanName + "'" : ""));
}
ScheduledExecutorService executor =
createExecutor(this.poolSize, this.threadFactory, this.rejectedExecutionHandler);
// Register specified ScheduledExecutorTasks, if necessary.

if (!ObjectUtils.isEmpty(this.scheduledExecutorTasks)) {
registerTasks(this.scheduledExecutorTasks, executor);
}
// Wrap executor with an unconfigurable decorator.

this.executor = (this.exposeUnconfigurableExecutor ?
Executors.unconfigurableScheduledExecutorService(executor) : executor);
}

public void afterPropertiesSet() {
if (logger.isInfoEnabled()) {
logger.info("Initializing ScheduledExecutorService" +
(this.beanName != null ? " '" + this.beanName + "'" : ""));
}
ScheduledExecutorService executor =
createExecutor(this.poolSize, this.threadFactory, this.rejectedExecutionHandler);
// Register specified ScheduledExecutorTasks, if necessary.
if (!ObjectUtils.isEmpty(this.scheduledExecutorTasks)) {
registerTasks(this.scheduledExecutorTasks, executor);
}
// Wrap executor with an unconfigurable decorator.
this.executor = (this.exposeUnconfigurableExecutor ?
Executors.unconfigurableScheduledExecutorService(executor) : executor);
}

SchedulerFactoryBean

[c-sharp]
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public void afterPropertiesSet() throws Exception {
.....
// 初始化sceduler

initSchedulerFactory(schedulerFactory);
this.scheduler = createScheduler(schedulerFactory, this.schedulerName);
//注册listener、trigger和job

registerListeners();
registerJobsAndTriggers();
......
//启动scheduler
startScheduler(this.scheduler, this.startupDelay);
......
}
}

public void afterPropertiesSet() throws Exception {
.....
// 初始化sceduler
initSchedulerFactory(schedulerFactory);
this.scheduler = createScheduler(schedulerFactory, this.schedulerName);
//注册listener、trigger和job
registerListeners();
registerJobsAndTriggers();
......
//启动scheduler
startScheduler(this.scheduler, this.startupDelay);
......
}
}

顺着scheduler->trigger->job的思路，Spring又分别对JDK Timer、concurrent、quartz的trigger进行了封装，暴露出时间调度的配置参数，三种封装类分别为ScheduledTimerTask、ScheduledExecutorTask和CronTriggerBean+SimpleTriggerBean。三种trigger封装类分别根据实现机制的特点暴露出时间调度配置并串联起scheduler和具体job任务