spring-boot @Async 的使用、自定义Executor的配置方法
简单几步，实现异步新线程调用。
1、在主类中添加@EnableAsync注解：
@SpringBootApplication
@EnableScheduling
@EnableAsync
public class MySpringBootApplication {
private static Logger logger = LoggerFactory.getLogger(MySpringBootApplication.class);
public static void main(String[] args) {
SpringApplication.run(MySpringBootApplication.class, args);
logger.info("My Spring Boot Application Started");
}
}2、创建一个AsyncTask类，在里面添加两个用@Async注解的task：
/**
* Asynchronous Tasks
* @author Xu
*
*/
@Component
public class AsyncTask {
protected final Logger logger = LoggerFactory.getLogger(this.getClass());
@Async
public Future doTask1() throws InterruptedException{
logger.info("Task1 started.");
long start = System.currentTimeMillis();
Thread.sleep(5000);
long end = System.currentTimeMillis();
logger.info("Task1 finished, time elapsed: {} ms.", end-start);
return new AsyncResult<>("Task1 accomplished!");
}
@Async
public Future doTask2() throws InterruptedException{
logger.info("Task2 started.");
long start = System.currentTimeMillis();
Thread.sleep(3000);
long end = System.currentTimeMillis();
logger.info("Task2 finished, time elapsed: {} ms.", end-start);
return new AsyncResult<>("Task2 accomplished!");
}
} public class TaskTests extends BasicUtClass{
@Autowired
private AsyncTask asyncTask;
@Test
public void AsyncTaskTest() throws InterruptedException, ExecutionException {
Future task1 = asyncTask.doTask1();
Future task2 = asyncTask.doTask2();
while(true) {
if(task1.isDone() && task2.isDone()) {
logger.info("Task1 result: {}", task1.get());
logger.info("Task2 result: {}", task2.get());
break;
}
Thread.sleep(1000);
}
logger.info("All tasks finished.");
}
} 测试结果：
2016-12-13 11:12:24,850:INFO main (AsyncExecutionAspectSupport.java:245) - No TaskExecutor bean found for async processing
2016-12-13 11:12:24,864:INFO SimpleAsyncTaskExecutor-1 (AsyncTask.java:22) - Task1 started.
2016-12-13 11:12:24,865:INFO SimpleAsyncTaskExecutor-2 (AsyncTask.java:34) - Task2 started.
2016-12-13 11:12:27,869:INFO SimpleAsyncTaskExecutor-2 (AsyncTask.java:39) - Task2 finished, time elapsed: 3001 ms.
2016-12-13 11:12:29,866:INFO SimpleAsyncTaskExecutor-1 (AsyncTask.java:27) - Task1 finished, time elapsed: 5001 ms.
2016-12-13 11:12:30,853:INFO main (TaskTests.java:23) - Task1 result: Task1 accomplished!
2016-12-13 11:12:30,853:INFO main (TaskTests.java:24) - Task2 result: Task2 accomplished!
2016-12-13 11:12:30,854:INFO main (TaskTests.java:30) - All tasks finished.可以看到，没有自定义的Executor，所以使用缺省的TaskExecutor 。
前面是最简单的使用方法。如果想使用自定义的Executor，可以按照如下几步来：
1、新建一个Executor配置类，顺便把@EnableAsync注解搬到这里来：
@Configuration
@EnableAsync
public class ExecutorConfig {
/** Set the ThreadPoolExecutor's core pool size. */
private int corePoolSize = 10;
/** Set the ThreadPoolExecutor's maximum pool size. */
private int maxPoolSize = 200;
/** Set the capacity for the ThreadPoolExecutor's BlockingQueue. */
private int queueCapacity = 10;
@Bean
public Executor mySimpleAsync() {
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
executor.setCorePoolSize(corePoolSize);
executor.setMaxPoolSize(maxPoolSize);
executor.setQueueCapacity(queueCapacity);
executor.setThreadNamePrefix("MySimpleExecutor-");
executor.initialize();
return executor;
}
@Bean
public Executor myAsync() {
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
executor.setCorePoolSize(corePoolSize);
executor.setMaxPoolSize(maxPoolSize);
executor.setQueueCapacity(queueCapacity);
executor.setThreadNamePrefix("MyExecutor-");
// rejection-policy：当pool已经达到max size的时候，如何处理新任务
// CALLER_RUNS：不在新线程中执行任务，而是有调用者所在的线程来执行
executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
executor.initialize();
return executor;
}
}这里定义了两个不同的Executor，第二个重新设置了pool已经达到max size时候的处理方法；同时指定了线程名字的前缀。
2、自定义Executor的使用：
/**
* Asynchronous Tasks
* @author Xu
*
*/
@Component
public class AsyncTask {
protected final Logger logger = LoggerFactory.getLogger(this.getClass());
@Async("mySimpleAsync")
public Future doTask1() throws InterruptedException{
logger.info("Task1 started.");
long start = System.currentTimeMillis();
Thread.sleep(5000);
long end = System.currentTimeMillis();
logger.info("Task1 finished, time elapsed: {} ms.", end-start);
return new AsyncResult<>("Task1 accomplished!");
}
@Async("myAsync")
public Future doTask2() throws InterruptedException{
logger.info("Task2 started.");
long start = System.currentTimeMillis();
Thread.sleep(3000);
long end = System.currentTimeMillis();
logger.info("Task2 finished, time elapsed: {} ms.", end-start);
return new AsyncResult<>("Task2 accomplished!");
}
} 3、测试（测试用例不变）结果：
2016-12-13 10:57:11,998:INFO MySimpleExecutor-1 (AsyncTask.java:22) - Task1 started.
2016-12-13 10:57:12,001:INFO MyExecutor-1 (AsyncTask.java:34) - Task2 started.
2016-12-13 10:57:15,007:INFO MyExecutor-1 (AsyncTask.java:39) - Task2 finished, time elapsed: 3000 ms.
2016-12-13 10:57:16,999:INFO MySimpleExecutor-1 (AsyncTask.java:27) - Task1 finished, time elapsed: 5001 ms.
2016-12-13 10:57:17,994:INFO main (TaskTests.java:23) - Task1 result: Task1 accomplished!
2016-12-13 10:57:17,994:INFO main (TaskTests.java:24) - Task2 result: Task2 accomplished!
2016-12-13 10:57:17,994:INFO main (TaskTests.java:30) - All tasks finished.
2016-12-13 10:57:18,064 Thread-3 WARN Unable to register Log4j shutdown hook because JVM is shutting down. Using SimpleLogger可见，线程名字的前缀变了，两个task使用了不同的线程池了。
源代码：https://github.com/xujijun/my-spring-boot