一文带你读懂SpringBoot 如何使用多线程_springboot多线程执行方法

前言

在实际开发过程中，我们可能会碰到以下情况，需要调用ABC三方法，但ABC三个方法的并没有逻辑关联，允许并行的运行，这个时候可以考虑采用异步的方式分别执行三个任务, 提升代码的运行效率。如果是想了解java代码是如何实现多线程的，可以参考这篇博客文章，本篇博客主要介绍SpringBoot是如何使用多线程，通过阅读本文，你经了解以下几个知识点：

1. SpringBoot项目是如何使用异步线程
2. SpringBoot是如何使用线程池
3. SpringBoot多线程源码相关知识

SpringBoot如何使用异步线程

通过@Async调用

第一步：在Application启动类上面加上@EnableAsync

@SpringBootApplication
@EnableAsync
public class DemoApplication {

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

}
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第二步：在需要异步执行的方法上加上@Async注解

@Service
public class AsyncDemo {
    protected final Logger logger = LoggerFactory.getLogger(this.getClass());
    @Async
    public void hello(String name) throws InterruptedException {
        logger.info("异步线程启动 started."+name);
        // 模拟方法耗时
        Thread.sleep(200);
    }
}
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第三步：测试类进行测试验证

@SpringBootTest(classes = DemoApplication.class)
@RunWith(SpringRunner.class)
public class AsyncTest {

    @Autowired
    public AsyncDemo asyncDemo;

    @Test
    public void contextLoads() throws InterruptedException {
        asyncDemo.hello("hello world");
        System.out.println(Thread.currentThread().getName()+"开始运行");
        Thread.sleep(1000);
        System.out.println(Thread.currentThread().getName()+"运行结束");
    }
}
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开启新线程执行，方法是异步执行，验证成功。

调用ThreadPoolTaskExecutor

第一步：在application文件添加SpringBoot线程池的配置

# 核心线程数
spring.task.execution.pool.core-size=8  
# 最大线程数
spring.task.execution.pool.max-size=16
# 空闲线程存活时间
spring.task.execution.pool.keep-alive=60s
# 是否允许核心线程超时
spring.task.execution.pool.allow-core-thread-timeout=true
# 线程队列数量
spring.task.execution.pool.queue-capacity=100
# 线程关闭等待
spring.task.execution.shutdown.await-termination=false
spring.task.execution.shutdown.await-termination-period=
# 线程名称前缀
spring.task.execution.thread-name-prefix=task-
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第二步：需要异步调用的方法, 可以不使用@Async, 启动类上可以不添加@EnableAsync

public void hello(String name) throws InterruptedException {
    //这里使用logger 方便查看执行的线程是什么
    logger.info("异步线程启动 started."+name);
    Thread.sleep(200);
}
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第三步：测试类进行测试验证

@SpringBootTest
class ThreadPoolApplicationTests {
    protected final Logger logger = LoggerFactory.getLogger(this.getClass());

    @Autowired
    AsyncTest asyncTest;
    @Autowired
    ThreadPoolTaskExecutor threadPoolTaskExecutor;
    @Test
    void contextLoads() throws InterruptedException {
        asyncTest.hello("async注解创建");
        threadPoolTaskExecutor.submit(new Thread(()->{
            logger.info("threadPoolTaskExecutor 创建线程");
        }));
        //一定要休眠 不然主线程关闭了，子线程还没有启动
        Thread.sleep(1000);
    }
}
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开启新线程执行，方法是异步执行，验证成功。

使用多个线程池

第一步：创建ThreadPoolConfig 配置多个线程池。

@Configuration
public class ThreadPoolConfig {

       @Bean("taskExecutor")
    public Executor taskExecutor() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        //设置线程池参数信息
        taskExecutor.setCorePoolSize(10);
        taskExecutor.setMaxPoolSize(50);
        taskExecutor.setQueueCapacity(200);
        taskExecutor.setKeepAliveSeconds(60);
        taskExecutor.setThreadNamePrefix("myExecutor--");
        taskExecutor.setWaitForTasksToCompleteOnShutdown(true);
        taskExecutor.setAwaitTerminationSeconds(60);
        //修改拒绝策略为使用当前线程执行
        taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        //初始化线程池
        taskExecutor.initialize();
        return taskExecutor;
    }

    @Bean("poolExecutor")
    public Executor poolExecutor() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        //设置线程池参数信息
        taskExecutor.setCorePoolSize(10);
        taskExecutor.setMaxPoolSize(50);
        taskExecutor.setQueueCapacity(200);
        taskExecutor.setKeepAliveSeconds(60);
        taskExecutor.setThreadNamePrefix("myExecutor2--");
        taskExecutor.setWaitForTasksToCompleteOnShutdown(true);
        taskExecutor.setAwaitTerminationSeconds(60);
        //修改拒绝策略为使用当前线程执行
        taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        //初始化线程池
        taskExecutor.initialize();
        return taskExecutor;
    }

    @Bean("taskPoolExecutor")
    public Executor taskPoolExecutor() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        //设置线程池参数信息
        taskExecutor.setCorePoolSize(10);
        taskExecutor.setMaxPoolSize(50);
        taskExecutor.setQueueCapacity(200);
        taskExecutor.setKeepAliveSeconds(60);
        taskExecutor.setThreadNamePrefix("myExecutor3--");
        taskExecutor.setWaitForTasksToCompleteOnShutdown(true);
        taskExecutor.setAwaitTerminationSeconds(60);
        //修改拒绝策略为使用当前线程执行
        taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        //初始化线程池
        taskExecutor.initialize();
        return taskExecutor;
    }
}
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第二步：需要异步调用的方法, 可以不使用@Async, 启动类上可以不添加@EnableAsync

public void hello(String name) throws InterruptedException {
    //这里使用logger 方便查看执行的线程是什么
    logger.info("异步线程启动 started."+name);
    Thread.sleep(200);
}
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第三步：测试类进行测试验证

@SpringBootTest(classes = DemoApplication.class)
@RunWith(SpringRunner.class)
public class MultipleThreadPoolTest {

    @Autowired
    AsyncDemo asyncDemo;

    @Autowired
    @Qualifier("poolExecutor")
    ThreadPoolTaskExecutor threadPoolTaskExecutor;

    @Test
    public void contextLoads() throws InterruptedException {
        System.out.println(Thread.currentThread().getName()+"开始运行");
        threadPoolTaskExecutor.submit(new Thread(() -> {
            try {
                asyncDemo.hello("异步方法调用");
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        }));
        Thread.sleep(1000);
        System.out.println(Thread.currentThread().getName()+"运行结束");
    }
}

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然后执行之前写的测试代码发现，使用的线程池已经变成自定义的线程池了。

SpringBoot线程源码