Spring Boot中@Async的作用

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.task.TaskExecutor;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.concurrent.Future;

@Configuration
@EnableAsync
public class SpringAsyncConfig {

    @Bean("taskExecutor")
    public TaskExecutor taskExecutor(){
        ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();
        threadPoolTaskExecutor.setThreadNamePrefix("taskExecutor");
        threadPoolTaskExecutor.setCorePoolSize(10);
        threadPoolTaskExecutor.setMaxPoolSize(30);
        threadPoolTaskExecutor.setQueueCapacity(100);
        threadPoolTaskExecutor.afterPropertiesSet();
        return threadPoolTaskExecutor;
    }

    @Async  //标注使用
    public void asyncMethodWithVoidReturnType() {
        System.out.println("Execute method asynchronously. "
                + Thread.currentThread().getName());
    }


    @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;
    }

    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(SpringAsyncConfig.class);

        SpringAsyncConfig bean = (SpringAsyncConfig) context.getBean("springAsyncConfig");

        bean.asyncMethodWithReturnType();
    }

}