主线程等待线程池里所有线程执行完成之后再执行

主线程等待线程池里所有线程执行完成之后再执行

1. 使用CountDownLatch来实现

public class TestThread {
   private static ThreadPoolExecutor threadPool = new ThreadPoolExecutor(50, 100,
           60L, TimeUnit.SECONDS, new LinkedBlockingDeque<>(), new ThreadFactoryBuilder().setNameFormat("job-task-%d").build());

   public static void execute(Runnable runnable) {
       threadPool.execute(runnable);
   }

   public static void shutDown() {
       threadPool.shutdown();
   }

   public static void main(String[] args) {
       List list = new ArrayList<String>();
       list.add("a");list.add("b");list.add("c");list.add("d");list.add("e");list.add("f");
       final CountDownLatch latch = new CountDownLatch(list.size());
       System.out.println("kaishile ！");
       list.stream().forEach(x->{
           TestThread.execute(()-> test((String) x,latch));
       });
       try {
           latch.await();
       } catch (InterruptedException e) {
           e.printStackTrace();
       }
       System.out.println("=====主线程执行完成了！");
       TestThread.shutDown();
       System.out.println("=====线程池关闭了！");
   }

   public static void test(String a,CountDownLatch latch){
       System.out.println(a);
       latch.countDown();
   }
}

===========================================
打印内容如下：
kaishile ！
a
b
c
d
e
f
=====主线程执行完成了！
=====线程池关闭了！

Process finished with exit code 0