注释类型 EnableScheduling
@Target(TYPE) @Retention(RUNTIME) @Import(SchedulingConfiguration.class) @Documented public @interface EnableScheduling
Enables Spring's scheduled task execution capability, similar to functionality found in Spring's<task:*>
XML namespace. To be used on @Configuration
classes as follows:@Configuration @EnableScheduling public class AppConfig { // various @Bean definitions }
This enables detection of @Scheduled
annotations on any Spring-managed bean in the container. For example, given a classMyTask
package com.myco.tasks; public class MyTask { @Scheduled(fixedRate=1000) public void work() { // task execution logic } }
the following configuration would ensure thatMyTask.work()
is called once every 1000 ms:@Configuration @EnableScheduling public class AppConfig { @Bean public MyTask task() { return new MyTask(); } }
Alternatively, ifMyTask
were annotated with@Component
, the following configuration would ensure that its@Scheduled
method is invoked at the desired interval:@Configuration @EnableScheduling @ComponentScan(basePackages="com.myco.tasks") public class AppConfig { }
Methods annotated with@Scheduled
may even be declared directly within@Configuration
classes:@Configuration @EnableScheduling public class AppConfig { @Scheduled(fixedRate=1000) public void work() { // task execution logic } }
By default, will be searching for an associated scheduler definition: either a unique
TaskScheduler
bean in the context, or aTaskScheduler
bean named "taskScheduler" otherwise; the same lookup will also be performed for aScheduledExecutorService
bean. If neither of the two is resolvable, a local single-threaded default scheduler will be created and used within the registrar.When more control is desired, a
@Configuration
class may implementSchedulingConfigurer
. This allows access to the underlyingScheduledTaskRegistrar
instance. For example, the following example demonstrates how to customize theExecutor
used to execute scheduled tasks:@Configuration @EnableScheduling public class AppConfig implements SchedulingConfigurer { @Override public void configureTasks(ScheduledTaskRegistrar taskRegistrar) { taskRegistrar.setScheduler(taskExecutor()); } @Bean(destroyMethod="shutdown") public Executor taskExecutor() { return Executors.newScheduledThreadPool(100); } }
Note in the example above the use of
@Bean(destroyMethod="shutdown")
. This ensures that the task executor is properly shut down when the Spring application context itself is closed.Implementing
SchedulingConfigurer
also allows for fine-grained control over task registration via theScheduledTaskRegistrar
. For example, the following configures the execution of a particular bean method per a customTrigger
implementation:@Configuration @EnableScheduling public class AppConfig implements SchedulingConfigurer { @Override public void configureTasks(ScheduledTaskRegistrar taskRegistrar) { taskRegistrar.setScheduler(taskScheduler()); taskRegistrar.addTriggerTask( new Runnable() { public void run() { myTask().work(); } }, new CustomTrigger() ); } @Bean(destroyMethod="shutdown") public Executor taskScheduler() { return Executors.newScheduledThreadPool(42); } @Bean public MyTask myTask() { return new MyTask(); } }
For reference, the example above can be compared to the following Spring XML configuration:
<beans> <task:annotation-driven scheduler="taskScheduler"/> <task:scheduler id="taskScheduler" pool-size="42"/> <task:scheduled-tasks scheduler="taskScheduler"> <task:scheduled ref="myTask" method="work" fixed-rate="1000"/> </task:scheduled-tasks> <bean id="myTask" class="com.foo.MyTask"/> </beans>
Trigger
implementation; this is because thetask:
namespacescheduled
cannot easily expose such support. This is but one demonstration how the code-based approach allows for maximum configurability through direct access to actual componentry.- 从以下版本开始:
- 3.1
- 作者:
- Chris Beams, Juergen Hoeller
- 另请参阅:
Scheduled
,SchedulingConfiguration
,SchedulingConfigurer
,ScheduledTaskRegistrar
,Trigger
,ScheduledAnnotationBeanPostProcessor