JUC系列学习工具类CountDownLatch详解

public class JoinAThread extends Thread
{
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName() + 
                " 线程开始");
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
         System.out.println( Thread.currentThread().getName() + 
                " 线程执行完毕");
    }
}

public class JoinBThread extends Thread
{
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName() + 
                " 线程开始");
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
         System.out.println( Thread.currentThread().getName() + 
                " 线程执行完毕");
    }
}

public class JoinTest
{
   public static void main(String[] args) throws InterruptedException
{
       JoinAThread joinA =new JoinAThread();
       Thread threadA =new Thread(joinA,"线程A");

       JoinBThread joinB =new JoinBThread();
       Thread threadB =new Thread(joinB,"线程B");
       threadA.start();
       threadB.start();
       threadA.join();
       threadB.join();

       System.out.println("子线程执行完成了，主线程"+Thread.currentThread().getName()+"开始执行了");
     }
}

public class CountDownLatchTest
{
    private static Logger logger =LoggerFactory.getLogger(CountDownLatchTest.class);
    public static void main(String[] args) throws InterruptedException
    {
        ExecutorService exec = Executors.newCachedThreadPool();
        final CountDownLatch countDownLatch = new CountDownLatch(10);
        for (int i = 1; i <= 10; i++){
            exec.execute(() -> {
                try {
                    invokeServiec();
                } catch (InterruptedException e) 
                {
                    logger.info("invoce service error",e);
                }
                finally 
                {
                    //计数器减一
                    countDownLatch.countDown();
                }
            });
        }
        countDownLatch.await();
        logger.info("所有的子线程执行完成,主线程"+Thread.currentThread().getName()+"开始执行");
    }

    private static void invokeServiec() throws InterruptedException
    {
        logger.info(Thread.currentThread().getName()+",开始执行任务");
        Thread.sleep(300);
    }
}