欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  IT编程

Spring Boot @Async 异步任务执行

程序员文章站 2022-09-08 21:30:59
1、任务执行和调度 Spring用TaskExecutor和TaskScheduler接口提供了异步执行和调度任务的抽象。 Spring的TaskExecutor和java.util.concurrent.Executor接口时一样的,这个接口只有一个方法execute(Runnable task) ......

1、任务执行和调度

SpringTaskExecutorTaskScheduler接口提供了异步执行和调度任务的抽象。

SpringTaskExecutorjava.util.concurrent.Executor接口时一样的,这个接口只有一个方法execute(Runnable task)

1.1、TaskExecutor类型

Spring已经内置了许多TaskExecutor的实现,你没有必要自己去实现:

  • SimpleAsyncTaskExecutor  这种实现不会重用任何线程,每次调用都会创建一个新的线程。
  • SyncTaskExecutor  这种实现不会异步的执行
  • ConcurrentTaskExecutor  这种实现是java.util.concurrent.Executor的一个adapter
  • SimpleThreadPoolTaskExecutor  这种实现实际上是Quartz的SimpleThreadPool的一个子类,它监听Spring的声明周期回调。
  • ThreadPoolTaskExecutor  这是最常用最通用的一种实现。它包含了java.util.concurrent.ThreadPoolExecutor的属性,并且用TaskExecutor进行包装。

1.2、注解支持调度和异步执行

To enable support for @Scheduled and @Async annotations add @EnableScheduling and @EnableAsync to one of your @Configuration classes:

@Configuration
@EnableAsync
@EnableScheduling
public class AppConfig {
}

特别注意

The default advice mode for processing @Async annotations is "proxy" which allows for interception of calls through the proxy only; local calls within the same class cannot get intercepted that way. For a more advanced mode of interception, consider switching to "aspectj" mode in combination with compile-time or load-time weaving.

默认是用代理去处理@Async的,因此,相同类中的方法调用带@Async的方法是无法异步的,这种情况仍然是同步。

举个例子:下面这种,在外部直接调用sayHi()是可以异步执行的,而调用sayHello()时sayHi()仍然是同步执行

public class A {
  
    public void sayHello() {
        sayHi();
    }

    @Async
    public void sayHi() {

    }   
  
}

1.3、@Async注解

在方法上加@Async注解表示这是一个异步调用。换句话说,方法的调用者会立即得到返回,并且实际的方法执行是想Spring的TaskExecutor提交了一个任务。

In other words, the caller will return immediately upon invocation and the actual execution of the method will occur in a task that has been submitted to a Spring TaskExecutor.

@Async
void doSomething() {
    // this will be executed asynchronously
}
@Async
void doSomething(String s) {
    // this will be executed asynchronously
}
@Async
Future<String> returnSomething(int i) {
    // this will be executed asynchronously
}

注意:

@Async methods may not only declare a regular java.util.concurrent.Future return type but also Spring’s org.springframework.util.concurrent.ListenableFuture or, as of Spring 4.2, JDK 8’s java.util.concurrent.CompletableFuture: for richer interaction with the asynchronous task and for immediate composition with further processing steps.

1.4、@Async限定Executor

默认情况下,当在方法上加@Async注解时,将会使用一个支持注解驱动的Executor。然而,@Async注解的value值可以指定一个别的Executor

@Async("otherExecutor")
void doSomething(String s) {
    // this will be executed asynchronously by "otherExecutor"
}

这里,otherExecutor是Spring容器中任意Executor bean的名字。

1.5、@Async异常管理

当一个@Async方法有一个Future类型的返回值时,就很容易管理在调Future的get()方法获取任务的执行结果时抛出的异常。如果返回类型是void,那么异常是不会被捕获到的。

public class MyAsyncUncaughtExceptionHandler implements AsyncUncaughtExceptionHandler {

    @Override
    public void handleUncaughtException(Throwable ex, Method method, Object... params) {
        // handle exception
    }
}

 2、线程池配置

 1
 3 import org.springframework.context.annotation.Bean;
 4 import org.springframework.context.annotation.Configuration;
 5 import org.springframework.scheduling.annotation.EnableAsync;
 6 import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
 7 
 8 @Configuration
 9 @EnableAsync
10 public class TaskExecutorConfig {
11 
12     private Integer corePoolSize = 30;
13 
14     private Integer maxPoolSize = 50;
15 
16     private Integer keepAliveSeconds = 300;
17 
18 //    private Integer queueCapacity = 2000;
19 
20     @Bean("myThreadPoolTaskExecutor")
21     public ThreadPoolTaskExecutor myThreadPoolTaskExecutor() {
22         ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
23         executor.setCorePoolSize(corePoolSize);
24         executor.setMaxPoolSize(maxPoolSize);
25         executor.setKeepAliveSeconds(keepAliveSeconds);
26 //        executor.setQueueCapacity(queueCapacity);
27         executor.setWaitForTasksToCompleteOnShutdown(true);
28         executor.initialize();
29         return executor;
30     }
31 
32 }

调用

 1     @Async("myThreadPoolTaskExecutor")
 2     @Override
 3     public void present(CouponPresentLogEntity entity) {
 4         try {
 5             CouponBaseResponse rst = couponSendRpcService.send(entity.getUserId(), entity.getCouponBatchKey(), "1", entity.getVendorId());
 6             if (null != rst && rst.isSuccess()) {
 7                 entity.setStatus(PresentStatusEnum.SUCCESS.getType());
 8             }else {
 9                 String reason = (null == rst) ? "响应异常" : rst.getMsg();
10                 entity.setFailureReason(reason);
11                 entity.setStatus(PresentStatusEnum.FAILURE.getType());
12             }
13         }catch (Exception ex) {
14             log.error(ex.getMessage(), ex);
15             entity.setFailureReason(ex.getMessage());
16             entity.setStatus(PresentStatusEnum.FAILURE.getType());
17         }
18         couponPresentLogDao.update(entity);
19     }

结果

[INFO ] 2018-05-09 16:27:39.887 [myThreadPoolTaskExecutor-1] [com.ourhours.coupon.rpc.dubbo.ReceiveLogFilter] - receive method-name:send; arguments:[10046031,"4d7cc32f8f7e4b00bca56f6bf4b3b658","1",10001]
[INFO ] 2018-05-09 16:27:39.889 [myThreadPoolTaskExecutor-2] [com.ourhours.coupon.rpc.dubbo.ReceiveLogFilter] - receive method-name:send; arguments:[10046031,"4d7cc32f8f7e4b00bca56f6bf4b3b658","1",10001]

 

 

 参考:

Spring Framework Reference Documentation 4.3.17.RELEASE

 Spring Boot @Async 异步任务执行