Task Execution and Scheduling

上下文内不存在 Executor Bean 时，Spring Boot 会自动配置一个 AsyncTaskExecutor 。当启用虚拟线程（使用 Java 21+ 并且将 configprop:spring.threads.virtual.enabled[] 设置为 true）时，它将是使用虚拟线程的 SimpleAsyncTaskExecutor 。否则，它将是具有合理默认值的 ThreadPoolTaskExecutor 。无论哪种情况，都会自动将自动配置的执行程序用于：

In the absence of an Executor bean in the context, Spring Boot auto-configures an AsyncTaskExecutor. When virtual threads are enabled (using Java 21+ and configprop:spring.threads.virtual.enabled[] set to true) this will be a SimpleAsyncTaskExecutor that uses virtual threads. Otherwise, it will be a ThreadPoolTaskExecutor with sensible defaults. In either case, the auto-configured executor will be automatically used for:

  • asynchronous task execution (@EnableAsync)

  • Spring for GraphQL’s asynchronous handling of Callable return values from controller methods

  • Spring MVC’s asynchronous request processing

  • Spring WebFlux’s blocking execution support

如果您已经定义了上下文中自定义的 Executor ，则常规任务执行（也就是 @EnableAsync）和 Spring for GraphQL 都将使用它。不过，如果它是一个 AsyncTaskExecutor 实现（名为 applicationTaskExecutor），则 Spring MVC 和 Spring WebFlux 支持只使用它。根据您的目标安排，您可以将 Executor 更改为 AsyncTaskExecutor ，或者定义一个 AsyncTaskExecutor 和一个 AsyncConfigurer 来包装您自定义的 Executor 。

If you have defined a custom Executor in the context, both regular task execution (that is @EnableAsync) and Spring for GraphQL will use it. However, the Spring MVC and Spring WebFlux support will only use it if it is an AsyncTaskExecutor implementation (named applicationTaskExecutor). Depending on your target arrangement, you could change your Executor into an AsyncTaskExecutor or define both an AsyncTaskExecutor and an AsyncConfigurer wrapping your custom Executor.

自动配置的 ThreadPoolTaskExecutorBuilder 允许你轻松地创建实例，这些实例会重现自动配置默认执行的操作。

The auto-configured ThreadPoolTaskExecutorBuilder allows you to easily create instances that reproduce what the auto-configuration does by default.

当自动配置 ThreadPoolTaskExecutor 时，线程池使用 8 个核心线程，这些线程可以根据负载增长和缩减。这些默认设置可以使用 spring.task.execution 命名空间进行微调，如下例所示：

When a ThreadPoolTaskExecutor is auto-configured, the thread pool uses 8 core threads that can grow and shrink according to the load. Those default settings can be fine-tuned using the spring.task.execution namespace, as shown in the following example:

spring:
  task:
    execution:
      pool:
        max-size: 16
        queue-capacity: 100
        keep-alive: "10s"

这更改了线程池，以便使用一个有界队列，因此当队列已满（100 个任务）时，线程池将增加到最多 16 个线程。线程池的缩减会更加激进，因为当线程空闲 10 秒（而不是默认的 60 秒）时，它们会被回收。

This changes the thread pool to use a bounded queue so that when the queue is full (100 tasks), the thread pool increases to maximum 16 threads. Shrinking of the pool is more aggressive as threads are reclaimed when they are idle for 10 seconds (rather than 60 seconds by default).

也可以自动配置调度程序，如果它需要与计划任务执行（例如，使用 @EnableScheduling）关联的话。

A scheduler can also be auto-configured if it needs to be associated with scheduled task execution (using @EnableScheduling for instance).

如果启用了虚拟线程（使用 Java 21+ 和将 configprop:spring.threads.virtual.enabled[] 设置为 true），这将是一个使用虚拟线程的 SimpleAsyncTaskScheduler。这个 SimpleAsyncTaskScheduler 将忽略任何与池相关的属性。

If virtual threads are enabled (using Java 21+ and configprop:spring.threads.virtual.enabled[] set to true) this will be a SimpleAsyncTaskScheduler that uses virtual threads. This SimpleAsyncTaskScheduler will ignore any pooling related properties.

如果未启用虚拟线程，它将是一个具有明智默认值的 ThreadPoolTaskScheduler。默认情况下 ThreadPoolTaskScheduler 使用一个线程，并且可以使用 spring.task.scheduling 命名空间来微调其设置，如下例所示：

If virtual threads are not enabled, it will be a ThreadPoolTaskScheduler with sensible defaults. The ThreadPoolTaskScheduler uses one thread by default and its settings can be fine-tuned using the spring.task.scheduling namespace, as shown in the following example:

spring:
  task:
    scheduling:
      thread-name-prefix: "scheduling-"
      pool:
        size: 2

如果需要创建自定义 executor 或调度程序，会在上下文中提供一个 ThreadPoolTaskExecutorBuilder bean、一个 SimpleAsyncTaskExecutorBuilder bean、一个 ThreadPoolTaskSchedulerBuilder bean 和一个 SimpleAsyncTaskSchedulerBuilder。如果启用了虚拟线程，则 SimpleAsyncTaskExecutorBuilder 和 SimpleAsyncTaskSchedulerBuilder bean 会自动配置为使用虚拟线程（使用 Java 21+ 和将 configprop:spring.threads.virtual.enabled[] 设置为 true）。

A ThreadPoolTaskExecutorBuilder bean, a SimpleAsyncTaskExecutorBuilder bean, a ThreadPoolTaskSchedulerBuilder bean and a SimpleAsyncTaskSchedulerBuilder are made available in the context if a custom executor or scheduler needs to be created. The SimpleAsyncTaskExecutorBuilder and SimpleAsyncTaskSchedulerBuilder beans are auto-configured to use virtual threads if they are enabled (using Java 21+ and configprop:spring.threads.virtual.enabled[] set to true).