- Java's asynchronous processing of Thread/Runnable, Callable/Future
- Asynchronous processing of Servlet 2.5 Tomcat's CometProcessor, Jetty's Continuations
- Asynchronous processing of Servlet 3.0 asyncSupported, AsyncContext
- Asynchronous processing of Spring MVC @Async, AsyncTaskExecutor
- Spring MVC的SSE ResponseBodyEmitter、SseEmitter、StreamingResponseBody
Spring Boot itself has not changed much for asynchronous calls, and it is basically Spring MVC's @Async.
(1) Turn on Spring's asynchronous support
@Configuration
@EnableAsync
public class SpringAsyncConfig {
}
Asynchronous processing is also automatically enabled when @EnableWebMvc is enabled, but @EnableWebMvc cannot be used in Spring Boot projects. It disables part of Spring Boot's AutoConfigure functionality.
There are instructions in the official documentation:
http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-spring-mvc-auto-configuration
@EnableWebMvc
@ComponentScan("com.example.component")
@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {
@Override
public void configureAsyncSupport(AsyncSupportConfigurer configurer) {
configure.setTaskExecutor (mvcAsyncExecutor ());
}
@Bean
public AsyncTaskExecutor mvcAsyncExecutor() {
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
executor.setMaxPoolSize(10);
return executor;
}
}
(2) Define a method that needs to perform asynchronous processing
1) No return value
@Async
public void asyncMethodWithVoidReturnType() {
System.out.println("Execute method asynchronously. "
+ Thread.currentThread().getName());
}
2) with return value
@Async
public Future<String> asyncMethodWithReturnType() {
System.out.println("Execute method asynchronously - "
+ Thread.currentThread().getName());
try {
Thread.sleep(5000);
return new AsyncResult<String>("hello world !");
} catch (InterruptedException e) {
}
return null;
}
(3) Definition of asynchronous thread pool
1) A thread pool
@Configuration
@EnableAsync
public class SpringAsyncConfig {
@Bean
public AsyncTaskExecutor taskExecutor() {
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
executor.setMaxPoolSize(10);
return executor;
}
}
2) Multiple thread pools
@Configuration
@EnableAsync
public class SpringAsyncConfig {
@Bean(name = "threadPoolTaskExecutor1")
public Executor threadPoolTaskExecutor() {
return new ThreadPoolTaskExecutor();
}
@Bean(name = "threadPoolTaskExecutor2")
public Executor threadPoolTaskExecutor() {
return new ThreadPoolTaskExecutor();
}
}
@Async("threadPoolTaskExecutor1")
public void asyncMethodWithConfiguredExecutor() {
System.out.println("Execute method with configured executor - "
+ Thread.currentThread().getName());
}
(4) Handling of asynchronous exceptions
public interface AsyncConfigurer {
Executor getAsyncExecutor();
AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler();
}
AsyncConfigurerSupport is an implementation of the AsyncConfigurer interface but does nothing in it.
@Configuration
@EnableAsync
class SpringAsyncConfigurer extends AsyncConfigurerSupport {
@Bean
public ThreadPoolTaskExecutor asyncExecutor() {
ThreadPoolTaskExecutor threadPool = new ThreadPoolTaskExecutor();
threadPool.setCorePoolSize(3);
threadPool.setMaxPoolSize(3);
threadPool.setWaitForTasksToCompleteOnShutdown(true);
threadPool.setAwaitTerminationSeconds(60 * 15);
return threadPool;
}
@Override
public Executor getAsyncExecutor() {
return asyncExecutor;
}
}
You can implement the AsyncConfigurer interface yourself to handle exceptions.
@Configuration
@EnableAsync
public class SpringAsyncConfigurer implements AsyncConfigurer {
@Override
public Executor getAsyncExecutor() {
return new ThreadPoolTaskExecutor();
}
@Override
public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
return new CustomAsyncExceptionHandler();
}
}
public class CustomAsyncExceptionHandler implements AsyncUncaughtExceptionHandler {
@Override
public void handleUncaughtException(Throwable throwable, Method method, Object... obj) {
System.out.println("Exception message - " + throwable.getMessage());
System.out.println("Method name - " + method.getName());
for (Object param : obj) {
System.out.println("Parameter value - " + param);
}
}
}
Reference:
http://qiita.com/kazuki43zoo/items/8be79f98621f90865b78
http://qiita.com/kazuki43zoo/items/ce88dea403c596249e8a
http://qiita.com/kazuki43zoo/items/53b79fe91c41cc5c2e59