【Spring】利用Spring最简单地使用异步方法

有时候我们想异步地调用某个方法。
比如这个场景：在业务处理完毕后，需给用户发送通知邮件。由于邮件发送需调用邮箱服务商，有可能发生阻塞，我们就可以异步调用。当然有个前提，即如果邮件发送失败，不需要提示用户的。

> 版本说明

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>3.2.14.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.webflow</groupId>
        <artifactId>spring-webflow</artifactId>
        <version>2.3.4.RELEASE</version>
    </dependency>
</dependencies>

> 一个简单的异步方法

package service;

import java.util.concurrent.TimeUnit;

import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

@Service
public class BusinessService {

    @Async
    public void doBusiness() throws InterruptedException {
        System.out.println("start to do business.");
        TimeUnit.SECONDS.sleep(5);
        System.out.println("end to do business.");
    }

}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:util="http://www.springframework.org/schema/util"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:task="http://www.springframework.org/schema/task"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
           http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
           http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.2.xsd">

    <!-- 扫描指定包下的组件 -->
    <context:component-scan base-package="service"/>

    <!-- 支持异步方法 -->
    <task:annotation-driven/>

</beans>

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import service.BusinessService;

public class HowToTest {

    public static void main(String[] args) throws InterruptedException {
        ApplicationContext context =
                new ClassPathXmlApplicationContext("spring.xml");
        BusinessService s = context.getBean("businessService", BusinessService.class);

        s.doBusiness();
        System.out.println("HowToTest completed.");

    }

}

日志是这样的

HowToTest completed.
start to do business.
end to do business.