关于springboot:SpringBoot使用异步EnableAsyncAsync

Spring boot 通过 @EnableAsync、@Async 配合来实现异步调用的。

举一个理发店的例子吧，比方 3 位理发师，5 位顾客来理发。

上面上代码

通过 @EnableAsync、@Configuration 配置一个默认的线程池，充当理发师
CorePoolSize(3); 即 3 位理发师

import org.springframework.aop.interceptor.AsyncExecutionAspectSupport;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;

@EnableAsync
@Configuration
public class ThreadPoolConfig {@Bean(name = AsyncExecutionAspectSupport.DEFAULT_TASK_EXECUTOR_BEAN_NAME)
    public Executor taskExecutor() {ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(3);
        executor.setMaxPoolSize(3);
        executor.setQueueCapacity(10);
        executor.setKeepAliveSeconds(60);
        executor.setThreadGroupName("理发师 -");
        executor.setWaitForTasksToCompleteOnShutdown(true);
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        return executor;
    }
}

理发业务,haircut 办法下面增加 @Async(value = "taskExecutor")示意办法异步，异步的办法不能被以后类的办法相互调用，在同一个类外部调用一个异步办法，不会触发异步

import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

import java.util.concurrent.CountDownLatch;

@Service
@Slf4j
public class DemoServiceImpl {@Async(value = "taskExecutor")
    public void haircut(CountDownLatch countDownLatch, String user) {log.info("用户:{}, 开始理发", user);
        try {
            // 模仿耗时
            Thread.sleep(5000L);
        } catch (InterruptedException e) { }
        log.info("用户:{}, 理发实现", user);
        countDownLatch.countDown();}
}

写一个单侧，营业开始，5 为顾客来理发，都理发实现，营业完结

import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.concurrent.CountDownLatch;

@SpringBootTest
@Slf4j
public class DemoServiceImplTest {

    @Autowired
    private DemoServiceImpl demoService;

    @Test
    public void haircutBusiness() {log.info("理发店: 开始营业");
        CountDownLatch countDownLatch = new CountDownLatch(5);
        demoService.haircut(countDownLatch, "张三");
        demoService.haircut(countDownLatch, "李四");
        demoService.haircut(countDownLatch, "王五");
        demoService.haircut(countDownLatch, "马六");
        demoService.haircut(countDownLatch, "孙七");
        try {countDownLatch.await();
        } catch (InterruptedException e) { }
        log.info("理发店: 敞开营业");
    }
}

运行后果如下：工夫点和成果合乎预期

CountDownLatch 定义了 5 个顾客同时来理发，理论并发还是依照线程池配置 3 个理发师来解决的

2022-10-19 18:04:10.356 [main] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImplTest[19] - 理发店: 开始营业
2022-10-19 18:04:10.363 [taskExecutor-1] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImpl[15] - 用户: 张三, 开始理发
2022-10-19 18:04:10.363 [taskExecutor-2] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImpl[15] - 用户: 李四, 开始理发
2022-10-19 18:04:10.363 [taskExecutor-3] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImpl[15] - 用户: 王五, 开始理发
2022-10-19 18:04:15.379 [taskExecutor-3] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImpl[20] - 用户: 王五, 理发实现
2022-10-19 18:04:15.379 [taskExecutor-3] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImpl[15] - 用户: 马六, 开始理发
2022-10-19 18:04:15.379 [taskExecutor-1] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImpl[20] - 用户: 张三, 理发实现
2022-10-19 18:04:15.380 [taskExecutor-2] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImpl[20] - 用户: 李四, 理发实现
2022-10-19 18:04:15.380 [taskExecutor-1] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImpl[15] - 用户: 孙七, 开始理发
2022-10-19 18:04:20.380 [taskExecutor-3] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImpl[20] - 用户: 马六, 理发实现
2022-10-19 18:04:20.380 [taskExecutor-1] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImpl[20] - 用户: 孙七, 理发实现
2022-10-19 18:04:20.381 [main] INFO  org.sauceggplant.manage.demo.service.impl.DemoServiceImplTest[29] - 理发店: 敞开营业

感兴趣童鞋能够本人试一下，good luck!