spring async异步线程任务简例

心已赠人 2023-10-01 12:58 9阅读 0赞

spring通过一个注解关键字 @Async 表明一段代码将放入异步线程代码块里面运行。

import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.scheduling.annotation.Async;
    import org.springframework.stereotype.Service;
    
    import java.util.concurrent.CompletableFuture;
    
    
    @Service
    public class MyService {
        private static final Logger logger = LoggerFactory.getLogger(MyService.class);
    
        public MyService() {
        }
    
        //这部分代码将放入到一个线程内完成。
        @Async
        public CompletableFuture<Integer> sum(int a, int b) throws InterruptedException {
            logger.info("计算: " + a + " + " + b);
            int s = a + b;
            Thread.sleep(3 * 1000);
            logger.info("计算: " + a + " + " + b + " 结束");
            return CompletableFuture.completedFuture(s);
        }
    }

上面代码示例计算两数之和，假设很耗时，所以放到线程里面执行。

定义一个runner：

import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.boot.CommandLineRunner;
    import org.springframework.stereotype.Component;
    
    import java.util.concurrent.CompletableFuture;
    
    @Component
    public class MyAppRunner implements CommandLineRunner {
        private static final Logger logger = LoggerFactory.getLogger(MyAppRunner.class);
        private final MyService myService;
    
        public MyAppRunner(MyService service) {
            this.myService = service;
        }
    
        @Override
        public void run(String... args) throws Exception {
            logger.info("-" + System.currentTimeMillis());
    
            CompletableFuture s1 = myService.sum(1, 2);
            CompletableFuture s2 = myService.sum(3, 4);
            CompletableFuture s3 = myService.sum(5, 6);
            CompletableFuture s4 = myService.sum(7, 8);
    
            //CompletableFuture.allOf(s1, s2, s3, s4).join();
    
            logger.info("--" + System.currentTimeMillis());
    
            logger.info("1,2--> " + s1.get());
            logger.info("3,4--> " + s2.get());
            logger.info("5,6--> " + s3.get());
            logger.info("7,8--> " + s4.get());
        }
    }

在spring的application里面关闭main()函数里面的线程池，取而代之由自己定义的一个线程池执行线程任务：

import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.scheduling.annotation.EnableAsync;
    import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
    
    import java.util.concurrent.Executor;
    
    @SpringBootApplication
    @EnableAsync
    public class SpringAsyncApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(SpringAsyncApplication.class, args).close();
        }
    
        @Bean
        public Executor taskExecutor() {
            ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
            executor.setCorePoolSize(10);
            executor.setMaxPoolSize(10);
            executor.setQueueCapacity(500);
            executor.setThreadNamePrefix("phil-thread:");
            executor.initialize();
            return executor;
        }
    }

运行日志输出（截取部分）：

:02:59.815  INFO 37044 --- [           main] c.e.spring_async.SpringAsyncApplication  : Started SpringAsyncApplication in 1.556 seconds (JVM running for 2.012)
    :02:59.817  INFO 37044 --- [           main] com.example.spring_async.MyAppRunner     : -1642158179816
    :02:59.821  INFO 37044 --- [           main] com.example.spring_async.MyAppRunner     : --1642158179820
    :02:59.827  INFO 37044 --- [  phil-thread:1] com.example.spring_async.MyService       : 计算: 1 + 2
    :02:59.827  INFO 37044 --- [  phil-thread:3] com.example.spring_async.MyService       : 计算: 5 + 6
    :02:59.827  INFO 37044 --- [  phil-thread:2] com.example.spring_async.MyService       : 计算: 3 + 4
    :02:59.827  INFO 37044 --- [  phil-thread:4] com.example.spring_async.MyService       : 计算: 7 + 8
    :03:02.832  INFO 37044 --- [  phil-thread:2] com.example.spring_async.MyService       : 计算: 3 + 4 结束
    :03:02.832  INFO 37044 --- [  phil-thread:4] com.example.spring_async.MyService       : 计算: 7 + 8 结束
    :03:02.832  INFO 37044 --- [  phil-thread:1] com.example.spring_async.MyService       : 计算: 1 + 2 结束
    :03:02.832  INFO 37044 --- [  phil-thread:3] com.example.spring_async.MyService       : 计算: 5 + 6 结束
    :03:02.832  INFO 37044 --- [           main] com.example.spring_async.MyAppRunner     : 1,2--> 3
    :03:02.832  INFO 37044 --- [           main] com.example.spring_async.MyAppRunner     : 3,4--> 7
    :03:02.832  INFO 37044 --- [           main] com.example.spring_async.MyAppRunner     : 5,6--> 11
    :03:02.832  INFO 37044 --- [           main] com.example.spring_async.MyAppRunner     : 7,8--> 15