Springboot中@scheduled注解解析

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Import(SchedulingConfiguration.class)
@Documented
public @interface EnableScheduling {
}

<task:annotation-driven>

@Configuration(proxyBeanMethods = false)
@Role(BeanDefinition.ROLE_INFRASTRUCTURE)
public class SchedulingConfiguration {
	@Bean(name = TaskManagementConfigUtils.SCHEDULED_ANNOTATION_PROCESSOR_BEAN_NAME)
	@Role(BeanDefinition.ROLE_INFRASTRUCTURE)
	public ScheduledAnnotationBeanPostProcessor scheduledAnnotationProcessor() {
		return new ScheduledAnnotationBeanPostProcessor();
	}
}

@Repeatable(Schedules.class)
public @interface Scheduled {
}

    @Scheduled(cron = "0 0 0 * * ?")
    @Scheduled(cron = "0 0 12 ? * WED")
    public void method() {
        System.err.println("hello world");
    }

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:task="http://www.springframework.org/schema/task"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/task
       http://www.springframework.org/schema/task/spring-task.xsd">
    <!-- 指定定时任务的执行者为下面定义的bean，这样就不会是默认的单线程执行任务了 --> 
	  <task:annotation-driven scheduler="schedule"/>
    <!-- 相当于引入了名为schedule的ThreadPoolTaskScheduler对象 -->
    <task:scheduler id="schedule" pool-size="5"/>
</beans>

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:task="http://www.springframework.org/schema/task"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/task
       http://www.springframework.org/schema/task/spring-task.xsd">
		<bean id="demoTask" class="tasks.DemoTask"/>
		<!-- 不指定scheduler会默认去找名为taskScheduler的bean，那么注解形式和xml形式的定时任务使用的就不是同一个线程池 -->
		<task:annotation-driven scheduler="scheduledjob"/>
    <task:scheduler id="scheduledjob" pool-size="10"/>  
    <!-- 这里不指定schedule的话，也是会默认去找名为taskScheduler的bean-->
    <task:scheduled-tasks scheduler="scheduledjob">
        <task:scheduled ref="demoTask" method="method2" fixed-rate="2000"/>
    </task:scheduled-tasks>
</beans>

private volatile int poolSize = 1;
	@Nullable
	private ScheduledExecutorService scheduledExecutor;
	this.scheduledExecutor = createExecutor(this.poolSize, threadFactory, rejectedExecutionHandler);

@Configuration
@EnableScheduling
public class ScheduledExecutorConfig implements SchedulingConfigurer {
    private final int corePoolSize = 10;
    private final String feature = "ScheduledTask";
    @Override
    public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) {
        // 方式一：创建一个ScheduledThreadPoolExecutor
        scheduledTaskRegistrar.setScheduler(taskExecutor());
        // 方式二 ：可议直接使用一个TaskScheduler  然后设置上poolSize等参数即可
//        ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();
//        taskScheduler.setPoolSize(corePoolSize);
//        taskScheduler.initialize(); // 手动初始化，同样会创建一个ScheduledThreadPoolExecutor
//        scheduledTaskRegistrar.setTaskScheduler(taskScheduler);
        // 题外话，通过这我们可以捕获到ScheduledTaskRegistrar，从而我们可以通过接口动态的去改变或添加任务
        scheduledTaskRegistrar.addFixedRateTask(() -> System.out.println("执行定时任务1: " + System.currentTimeMillis()), 1000);
    }
    @Bean(destroyMethod = "shutdown")
    public ScheduledExecutorService taskExecutor() {
        return new ScheduledThreadPoolExecutor(corePoolSize, new ThreadFactoryConfig(feature));
    }
}

    @Bean
    public TaskScheduler taskScheduler() {
        ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
        scheduler.setPoolSize(10);
        return scheduler;
    }