SpringBoot线程池

太过爱你忘了你带给我的痛 2022-09-10 01:28 173阅读 0赞

### 这里写自定义目录标题 ###

做公司项目的时候，前端需要批量导入大量数据，想通过线程异步实现，找了下相关资料，记录如下：  
  
Spring Boot项目，可以用Spring提供的对ThreadPoolExecutor封装的线程池ThreadPoolTaskExecutor，直接使用注解启用。

先创建一个线程池的配置，让Spring Boot加载，用来定义如何创建一个ThreadPoolTaskExecutor，要使用@Configuration和@EnableAsync这两个注解，表示这是个配置类，并且是线程池的配置类

@Configuration
    @EnableAsync
    public class ExecutorConfig { 
        private static final Logger logger = LoggerFactory.getLogger(ExecutorConfig.class);
    
        @Value("${async.executor.thread.core_pool_size}")
        private int corePoolSize;
        @Value("${async.executor.thread.max_pool_size}")
        private int maxPoolSize;
        @Value("${async.executor.thread.queue_capacity}")
        private int queueCapacity;
        @Value("${async.executor.thread.name.prefix}")
        private String namePrefix;
    
        @Bean(name = "asyncServiceExecutor")
        public Executor asyncServiceExecutor() { 
            logger.info("start asyncServiceExecutor");
            ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
            //配置核心线程数
            executor.setCorePoolSize(corePoolSize);
            //配置最大线程数
            executor.setMaxPoolSize(maxPoolSize);
            //配置队列大小
            executor.setQueueCapacity(queueCapacity);
            //配置线程池中的线程的名称前缀
            executor.setThreadNamePrefix(namePrefix);
    
            // rejection-policy：当pool已经达到max size的时候，如何处理新任务
            // CALLER_RUNS：不在新线程中执行任务，而是有调用者所在的线程来执行
            executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
            //执行初始化
            executor.initialize();
            return executor;
        }
    }

创建一个Service接口，是异步线程的接口

public interface AsyncService { 
       
         
        /** * 执行异步任务 * 可以根据需求，自己加参数拟定，我这里就做个测试演示 */
        void executeAsync();
    }

实现类

@Service
    public class AsyncServiceImpl implements AsyncService {       
        private static final Logger logger = LoggerFactory.getLogger(AsyncServiceImpl.class);
        @Override
        @Async("asyncServiceExecutor")
        public void executeAsync() { 
            logger.info("start executeAsync");
    
            System.out.println("异步线程要做的事情");
            System.out.println("可以在这里执行批量插入等耗时的事情");
            logger.info("end executeAsync");
        }
    }

将Service层的服务异步化，在executeAsync()方法上增加注解@Async(“asyncServiceExecutor”)，asyncServiceExecutor方法是前面ExecutorConfig.java中的方法名，表明executeAsync方法进入的线程池是asyncServiceExecutor方法创建的

接下来就是在Controller里或者是哪里通过注解@Autowired注入这个Service

@Autowired
    private AsyncService asyncService;
    @GetMapping("/async")
    public void async(){ 
        asyncService.executeAsync();
    }

用postmain或者其他工具来多次测试请求一下

2021-09-02 22:15:47.655  INFO 10516 --- [async-service-5] c.u.d.e.executor.impl.AsyncServiceImpl   : start executeAsync
    异步线程要做的事情
    可以在这里执行批量插入等耗时的事情
    2021-09-02 22:15:47.655  INFO 10516 --- [async-service-5] c.u.d.e.executor.impl.AsyncServiceImpl   : end executeAsync
    2021-09-02 22:15:47.770  INFO 10516 --- [async-service-1] c.u.d.e.executor.impl.AsyncServiceImpl   : start executeAsync
    异步线程要做的事情
    可以在这里执行批量插入等耗时的事情
    2021-09-02 22:15:47.770  INFO 10516 --- [async-service-1] c.u.d.e.executor.impl.AsyncServiceImpl   : end executeAsync
    2021-09-02 22:15:47.816  INFO 10516 --- [async-service-2] c.u.d.e.executor.impl.AsyncServiceImpl   : start executeAsync
    异步线程要做的事情
    可以在这里执行批量插入等耗时的事情
    2021-09-02 22:15:47.816  INFO 10516 --- [async-service-2] c.u.d.e.executor.impl.AsyncServiceImpl   : end executeAsync
    2021-09-02 22:15:48.833  INFO 10516 --- [async-service-3] c.u.d.e.executor.impl.AsyncServiceImpl   : start executeAsync
    异步线程要做的事情
    可以在这里执行批量插入等耗时的事情
    2021-09-02 22:15:48.834  INFO 10516 --- [async-service-3] c.u.d.e.executor.impl.AsyncServiceImpl   : end executeAsync
    2021-09-02 22:15:48.986  INFO 10516 --- [async-service-4] c.u.d.e.executor.impl.AsyncServiceImpl   : start executeAsync
    异步线程要做的事情
    可以在这里执行批量插入等耗时的事情
    2021-09-02 22:15:48.987  INFO 10516 --- [async-service-4] c.u.d.e.executor.impl.AsyncServiceImpl   : end executeAsync

通过以上日志可以发现，\[async-service-\]是有多个线程的，显然已经在我们配置的线程池中执行了，并且每次请求中，controller的起始和结束日志都是连续打印的，表明每次请求都快速响应了，而耗时的操作都留给线程池中的线程去异步执行；

虽然我们已经用上了线程池，但是还不清楚线程池当时的情况，有多少线程在执行，多少在队列中等待呢？这里我创建了一个ThreadPoolTaskExecutor的子类，在每次提交线程的时候都会将当前线程池的运行状况打印出来

import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
    import org.springframework.util.concurrent.ListenableFuture;
    
    import java.util.concurrent.Callable;
    import java.util.concurrent.Future;
    import java.util.concurrent.ThreadPoolExecutor;
    
    /** * @Author: ChenBin */
    public class VisiableThreadPoolTaskExecutor extends ThreadPoolTaskExecutor {  
    
        private static final Logger logger = LoggerFactory.getLogger(VisiableThreadPoolTaskExecutor.class);
    
        private void showThreadPoolInfo(String prefix) { 
            ThreadPoolExecutor threadPoolExecutor = getThreadPoolExecutor();
    
            if (null == threadPoolExecutor) { 
                return;
            }
    
            logger.info("{}, {},taskCount [{}], completedTaskCount [{}], activeCount [{}], queueSize [{}]",
                    this.getThreadNamePrefix(),
                    prefix,
                    threadPoolExecutor.getTaskCount(),
                    threadPoolExecutor.getCompletedTaskCount(),
                    threadPoolExecutor.getActiveCount(),
                    threadPoolExecutor.getQueue().size());
        }
    
        @Override
        public void execute(Runnable task) { 
            showThreadPoolInfo("1. do execute");
            super.execute(task);
        }
    
        @Override
        public void execute(Runnable task, long startTimeout) { 
            showThreadPoolInfo("2. do execute");
            super.execute(task, startTimeout);
        }
    
        @Override
        public Future<?> submit(Runnable task) { 
            showThreadPoolInfo("1. do submit");
            return super.submit(task);
        }
    
        @Override
        public <T> Future<T> submit(Callable<T> task) { 
            showThreadPoolInfo("2. do submit");
            return super.submit(task);
        }
    
        @Override
        public ListenableFuture<?> submitListenable(Runnable task) { 
            showThreadPoolInfo("1. do submitListenable");
            return super.submitListenable(task);
        }
    
        @Override
        public <T> ListenableFuture<T> submitListenable(Callable<T> task) { 
            showThreadPoolInfo("2. do submitListenable");
            return super.submitListenable(task);
        }
    }

如上所示，showThreadPoolInfo方法中将任务总数、已完成数、活跃线程数，队列大小都打印出来了，然后Override了父类的execute、submit等方法，在里面调用showThreadPoolInfo方法，这样每次有任务被提交到线程池的时候，都会将当前线程池的基本情况打印到日志中；

修改ExecutorConfig.java的asyncServiceExecutor方法，将ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor()改为ThreadPoolTaskExecutor executor = new VisiableThreadPoolTaskExecutor()

@Bean(name = "asyncServiceExecutor")
        public Executor asyncServiceExecutor() { 
            logger.info("start asyncServiceExecutor");
            //在这里修改
            ThreadPoolTaskExecutor executor = new VisiableThreadPoolTaskExecutor();
            //配置核心线程数
            executor.setCorePoolSize(corePoolSize);
            //配置最大线程数
            executor.setMaxPoolSize(maxPoolSize);
            //配置队列大小
            executor.setQueueCapacity(queueCapacity);
            //配置线程池中的线程的名称前缀
            executor.setThreadNamePrefix(namePrefix);
    
            // rejection-policy：当pool已经达到max size的时候，如何处理新任务
            // CALLER_RUNS：不在新线程中执行任务，而是有调用者所在的线程来执行
            executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
            //执行初始化
            executor.initialize();
            return executor;
        }

再次启动该工程测试

2021-09-02 22:23:30.951  INFO 14088 --- [nio-8087-exec-2] u.d.e.e.i.VisiableThreadPoolTaskExecutor : async-service-, 2. do submit,taskCount [0], completedTaskCount [0], activeCount [0], queueSize [0]
    2021-09-02 22:23:30.952  INFO 14088 --- [async-service-1] c.u.d.e.executor.impl.AsyncServiceImpl   : start executeAsync
    异步线程要做的事情
    可以在这里执行批量插入等耗时的事情
    2021-09-02 22:23:30.953  INFO 14088 --- [async-service-1] c.u.d.e.executor.impl.AsyncServiceImpl   : end executeAsync
    2021-09-02 22:23:31.351  INFO 14088 --- [nio-8087-exec-3] u.d.e.e.i.VisiableThreadPoolTaskExecutor : async-service-, 2. do submit,taskCount [1], completedTaskCount [1], activeCount [0], queueSize [0]
    2021-09-02 22:23:31.353  INFO 14088 --- [async-service-2] c.u.d.e.executor.impl.AsyncServiceImpl   : start executeAsync
    异步线程要做的事情
    可以在这里执行批量插入等耗时的事情
    2021-09-02 22:23:31.353  INFO 14088 --- [async-service-2] c.u.d.e.executor.impl.AsyncServiceImpl   : end executeAsync
    2021-09-02 22:23:31.927  INFO 14088 --- [nio-8087-exec-5] u.d.e.e.i.VisiableThreadPoolTaskExecutor : async-service-, 2. do submit,taskCount [2], completedTaskCount [2], activeCount [0], queueSize [0]
    2021-09-02 22:23:31.929  INFO 14088 --- [async-service-3] c.u.d.e.executor.impl.AsyncServiceImpl   : start executeAsync
    异步线程要做的事情
    可以在这里执行批量插入等耗时的事情
    2021-09-02 22:23:31.930  INFO 14088 --- [async-service-3] c.u.d.e.executor.impl.AsyncServiceImpl   : end executeAsync
    2021-09-02 22:23:32.496  INFO 14088 --- [nio-8087-exec-7] u.d.e.e.i.VisiableThreadPoolTaskExecutor : async-service-, 2. do submit,taskCount [3], completedTaskCount [3], activeCount [0], queueSize [0]
    2021-09-02 22:23:32.498  INFO 14088 --- [async-service-4] c.u.d.e.executor.impl.AsyncServiceImpl   : start executeAsync
    异步线程要做的事情
    可以在这里执行批量插入等耗时的事情
    2021-09-02 22:23:32.499  INFO 14088 --- [async-service-4] c.u.d.e.executor.impl.AsyncServiceImpl   : end executeAsync

注意这一行日志：

2021-09-02 22:23:32.496  INFO 14088 --- [nio-8087-exec-7] u.d.e.e.i.VisiableThreadPoolTaskExecutor : async-service-, 2. do submit,taskCount [3], completedTaskCount [3], activeCount [0], queueSize [0]

这说明提交任务到线程池的时候，调用的是submit(Callable task)这个方法，当前已经提交了3个任务，完成了3个，当前有0个线程在处理任务，还剩0个任务在队列中等待，线程池的基本情况一路了然。