/**
     * 用给定的初始参数创建一个新的ThreadPoolExecutor。
     */
    public ThreadPoolExecutor(int corePoolSize,//线程池的核心线程数量
                              int maximumPoolSize,//线程池的最大线程数
                              long keepAliveTime,//当线程数大于核心线程数时，多余的空闲线程存活的最长时间
                              TimeUnit unit,//时间单位
                              BlockingQueue<Runnable> workQueue,//任务队列，用来储存等待执行任务的队列
                              ThreadFactory threadFactory,//线程工厂，用来创建线程，一般默认即可
                              RejectedExecutionHandler handler//拒绝策略，当提交的任务过多而不能及时处理时，我们可以定制策略来处理任务
                               ) {
        if (corePoolSize < 0 ||
            maximumPoolSize <= 0 ||
            maximumPoolSize < corePoolSize ||
            keepAliveTime < 0)
            throw new IllegalArgumentException();
        if (workQueue == null || threadFactory == null || handler == null)
            throw new NullPointerException();
        this.corePoolSize = corePoolSize;
        this.maximumPoolSize = maximumPoolSize;
        this.workQueue = workQueue;
        this.keepAliveTime = unit.toNanos(keepAliveTime);
        this.threadFactory = threadFactory;
        this.handler = handler;
    }

private static final int CORE_POOL_SIZE = 5;
    private static final int MAX_POOL_SIZE = 10;
    private static final int QUEUE_CAPACITY = 100;
    private static final Long KEEP_ALIVE_TIME = 1L;

    public static void main(String[] args) {

        //使用阿里巴巴推荐的创建线程池的方式
        //通过ThreadPoolExecutor构造函数自定义参数创建
        ThreadPoolExecutor executor = new ThreadPoolExecutor(
                CORE_POOL_SIZE,
                MAX_POOL_SIZE,
                KEEP_ALIVE_TIME,
                TimeUnit.SECONDS,
                new ArrayBlockingQueue<>(QUEUE_CAPACITY),
                new ThreadPoolExecutor.CallerRunsPolicy());

        for (int i = 0; i < 10; i++) {
            executor.execute(() -> {
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println("CurrentThread name:" + Thread.currentThread().getName() + "date：" + Instant.now());
            });
        }
        //终止线程池
        executor.shutdown();
        try {
            /* 
            awaitTermination()方法的作用:
			当前线程阻塞，直到
			1. 等所有已提交的任务（包括正在跑的和队列中等待的）执行完
			2. 或者等超时时间到
			3. 或者线程被中断，抛出InterruptedException 然后返回true（shutdown请求后所有任务执行完毕）或false（已超时）
            */
            executor.awaitTermination(5, TimeUnit.SECONDS);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("Finished all threads");
    }
/*输出
 CurrentThread name:pool-1-thread-5date：2020-06-06T11:45:31.639Z
CurrentThread name:pool-1-thread-3date：2020-06-06T11:45:31.639Z
CurrentThread name:pool-1-thread-1date：2020-06-06T11:45:31.636Z
CurrentThread name:pool-1-thread-4date：2020-06-06T11:45:31.639Z
CurrentThread name:pool-1-thread-2date：2020-06-06T11:45:31.639Z
CurrentThread name:pool-1-thread-2date：2020-06-06T11:45:33.656Z
CurrentThread name:pool-1-thread-4date：2020-06-06T11:45:33.656Z
CurrentThread name:pool-1-thread-1date：2020-06-06T11:45:33.656Z
CurrentThread name:pool-1-thread-3date：2020-06-06T11:45:33.656Z
CurrentThread name:pool-1-thread-5date：2020-06-06T11:45:33.656Z
Finished all threads 
*/

    /**
     * 打印线程池的状态
     *
     * @param threadPool 线程池对象
     */
    public static void printThreadPoolStatus(ThreadPoolExecutor threadPool) {
        ScheduledExecutorService scheduledExecutorService = new ScheduledThreadPoolExecutor(1, createThreadFactory("print-images/thread-pool-status", false));
        scheduledExecutorService.scheduleAtFixedRate(() -> {
            log.info("=========================");
            log.info("ThreadPool Size: [{}]", threadPool.getPoolSize());
            log.info("Active Threads: {}", threadPool.getActiveCount());
            log.info("Number of Tasks : {}", threadPool.getCompletedTaskCount());
            log.info("Number of Tasks in Queue: {}", threadPool.getQueue().size());
            log.info("=========================");
        }, 0, 1, TimeUnit.SECONDS);
    }