spring 使用异步任务

1.说明

在springboot 中使用 @Async 实现异步任务处理，下面介绍一下如何实现这个。

2.实现代码

2.1 增加@EnableAsync

@EnableAsync
public class Demo1Application {

    public static void main(String[] args) {
        SpringApplication.run(Demo1Application.class, args);
    }

}

2.2 构造一个线程池

实现异步时，我们需要手工构造一个线程池，否则会出现内存泄漏的问题。

@Configuration
public class AsyncThreadPoolConfig {

    private static final int MAX_POOL_SIZE = 20;
    private static final int CORE_POOL_SIZE = 10;
    private static final int TASK_NUM = 200;
    private static final int ACTIVE_TIME = 60;

    @Bean("myExecutor")
    public AsyncTaskExecutor asyncTaskExecutor() {
        ThreadPoolTaskExecutor asyncTaskExecutor = new ThreadPoolTaskExecutor();
        asyncTaskExecutor.setMaxPoolSize(MAX_POOL_SIZE);
        asyncTaskExecutor.setCorePoolSize(CORE_POOL_SIZE);
        asyncTaskExecutor.setQueueCapacity(TASK_NUM);
        asyncTaskExecutor.setKeepAliveSeconds(ACTIVE_TIME);
        asyncTaskExecutor.setThreadNamePrefix("laozhang_");
        asyncTaskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        asyncTaskExecutor.initialize();
        return asyncTaskExecutor;
    }

}

2.3 使用注解

@Component
public class AsyncTest {

    @Async(value = "myExecutor")
    public  void longTime() throws InterruptedException {
        System.err.println("----------------start----------------");
        Thread.sleep(5000);
        System.err.println("----------------end----------------");
    }
}

增加一个@Async注解，表示这个方法会使用异步处理