業務介紹:

　　多執行緒執行春節車票售賣!

程式碼邏輯如下:

/**
 * 售票任務
 */
class TaskRunnable implements Runnable{

    /**
     * 剩餘車票數量
     */
    private AtomicInteger count;

    /**
     * 當前任務名稱
     */
    private String taskName;

    /**
     * 任務鎖
     */
    private ReentrantLock lock;

    public TaskRunnable(AtomicInteger count, String taskName, ReentrantLock lock) {
        
 
this.count = count;
        this.taskName = taskName;
        this.lock = lock;
    }

    @Override
    public void run() {
        System.out.println(taskName + "號售票廳的開始售票~~");
        while (true) {
            this.lock.lock();

            if (this.count.get() <= 0) {
                //任務結束解鎖
                this
 
.lock.unlock();
                break;
            }
            System.out.println("恭喜搶到" + taskName+"號銷售廳的車票! 當前剩餘車票數" + this.count.decrementAndGet());
            this.lock.unlock();
        }
        System.out.println(taskName+"號售票廳的售票結束--");
    }
}

/**
 * @author Kevin
 * @DateTime 2019/1/12 11:08
 * @Description
 
 
*/
public class ExecutorServiceL {

    public static void main(String[] args) {

        //建立執行緒池
        ExecutorService executorService = getExecutor();

        //執行任務
        executeTask(executorService);

        while (true) {
            if (((ThreadPoolExecutor) executorService).getActiveCount() <= 0) {
                System.out.println("售票結束~~");
                break;
            }
        }
        try {
            /**
             * 關閉執行緒池:
             * 1.不在接收新的任務
             * 2.等待已執行任務執行完畢
             * 3.關閉執行緒池(清除尚未執行任務,試圖停止正在執行的任務)
             */
            executorService.shutdown();
            if (!executorService.awaitTermination(2, TimeUnit.SECONDS)) {
                System.out.println("尚未執行任務列表: "+executorService.shutdownNow());
            }

        } catch (Exception e) {
            System.out.println("超出時間強制結束!");
        }
    }

    /**
     * 執行任務
     *
     * @param executorService
     */
    public static void executeTask(ExecutorService executorService) {

        //總車票數
        AtomicInteger total = new AtomicInteger(30);
        //執行緒鎖
        ReentrantLock lock = new ReentrantLock();

        executorService.execute(new TaskRunnable(total, "1", lock));
        executorService.execute(new TaskRunnable(total, "2", lock));
        executorService.execute(new TaskRunnable(total, "3", lock));
        executorService.execute(new TaskRunnable(total, "4", lock));
    }

    /**
     * 獲取執行緒池
     *
     * @return
     */
    public static ExecutorService getExecutor() {
        return new ThreadPoolExecutor(
                2,
                4,
                2,
                TimeUnit.SECONDS,
                new SynchronousQueue(),
                new ThreadPoolExecutor.DiscardOldestPolicy()
        );
    }
}