Introduction
Spring Boot provides annotation support for task scheduling. It is easy way to develop and run a Task scheduler without using any xml and bean configurations Simply add the annotation @Scheduled on the task scheduler method with required interval time. In this example, we will see how to use Spring @Scheduledannotation to schedule a task.
Enable scheduling annotations
To enable support for @Scheduled annotation add @EnableScheduling to one of your @Configuration classes:
You are free to pick and choose the relevant annotations for your application. For example, for more fine-grained control you can additionally implement the SchedulingConfigurer interfaces.
The @Scheduled annotation
The @Scheduled annotation can be added to a method along with trigger metadata.
Important: The simple rules that need to be followed to annotate a method with @Scheduled are:
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A method should not accept any parameters
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A method should have void return type
For example, the following method would be invoked every 5 seconds with a fixed delay, meaning that the period will be measured from the completion time of each preceding invocation.
If a fixed rate execution is desired, simply change the property name specified within the annotation.
The following would be executed every 5 seconds measured between the successive start times of each invocation.
For fixed-delay and fixed-rate tasks, an initial delay may be specified indicating the number of milliseconds to wait before the first execution of the method.
If simple periodic scheduling is not expressive enough, then a cron expression may be provided. For example, the following will only execute on weekdays.