thread46

package com.neutron.t23;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.TimeUnit;/** * 线程池接口 * 了解线程池 */public class T235ThreadPool {    public static void main(String[] args) throws InterruptedException {        // 创建固定大小为5的线程池，线程池都实现ExecutorService接口        ExecutorService service = Executors.newFixedThreadPool(5);        for (int i = 0; i < 6; i++) {            // 向ExecutorService可以扔Callable或Runnable类型的任务            service.execute(() -> {                try {                    TimeUnit.MILLISECONDS.sleep(500);                } catch (InterruptedException e) {                    e.printStackTrace();                }                System.out.println(Thread.currentThread().getName());            });        }        /*         java.util.concurrent.ThreadPoolExecutor@568db2f2         [Running, pool size = 5, active threads = 5, queued tasks = 1, completed tasks = 0]         Running表示线程池状态         pool size = 5表示线程池大小         active threads = 5表示当前活跃的线程个数         queued tasks = 1表示在队列等待执行的线程个数，程序中0-5共6个线程，但是目前线程池只有5个，那会有1个线程等待         线程执行完成，但是线程不消失，不需要重新启动新的线程         */        System.out.println(service);        // 线程池关闭，等待线程全部执行完毕，然后线程池关闭。        service.shutdown();        // 线程池关闭，但是不等待其他执行的线程，立刻关闭线程池        // service.shutdownNow();        // isTerminated判断所有的任务是否都执行完成        System.out.println(service.isTerminated());        // isShutdown判断线程池是否已经关闭，关闭进行中        System.out.println(service.isShutdown());        /*          java.util.concurrent.ThreadPoolExecutor@568db2f2          [Shutting down, pool size = 5, active threads = 5, queued tasks = 1, completed tasks = 0]          Shutting down表示正在关闭         */        System.out.println(service);        // 主线程休息5秒        TimeUnit.SECONDS.sleep(5);        System.out.println(service.isTerminated());        System.out.println(service.isShutdown());        /*            java.util.concurrent.ThreadPoolExecutor@568db2f2            [Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 6]            Terminated表示线程结束            completed tasks = 6表示完成任务个数         */        System.out.println(service);        /*         * 1个线程池维护两个队列：         *         * a.待处理任务队列         * b.已完成任务队列         */    }}