我们在开发程序的时候，需要多个线程执行任务，每个线程都执行不同的准备工作，但我们要同时执行这些程序要怎么做呢?接下来我们就来给大家讲解一下这方面的内容。
一是用CyclicBarrier (适用在多线程相互等待，直到到达一个屏障点。并且CyclicBarrier是可重用的。)实现。
代码实现：
public class CyclicBarrierTest
{
boolean finalFlg = false;
/**
* CyclicBarrier 适用再多线程相互等待，直到到达一个屏障点。并且CyclicBarrier是可重用的。
*/
CyclicBarrier cyclicBarrier = new CyclicBarrier(10);
private void runThread()
{
ExecutorService executorService = Executors.newFixedThreadPool(10);
for (int i = 0; i < 10; i++)
{
try
{
Thread.sleep(100);
}
catch (InterruptedException e)
{
e.printStackTrace();
}
executorService.submit(createThread(i));
}
}
private Thread createThread(int i)
{
Thread thread = new Thread(new Runnable()
{
@Override
public void run()
{
try
{
cyclicBarrier.await();
System.out.println("Thread:" + Thread.currentThread()
.getName() + "准备完毕,time:" + System.currentTimeMillis());
}
catch (InterruptedException e)
{
e.printStackTrace();
}
catch (BrokenBarrierException e)
{
e.printStackTrace();
}
}
});
thread.setName("name" + i);
return thread;
}
public static void main(String[] args)
{
CyclicBarrierTest test = new CyclicBarrierTest();
test.runThread();
}
}执行结果：
Thread:pool-1-thread-10准备完毕,time:1521037864652
Thread:pool-1-thread-1准备完毕,time:1521037864652
Thread:pool-1-thread-3准备完毕,time:1521037864652
Thread:pool-1-thread-2准备完毕,time:1521037864652
Thread:pool-1-thread-7准备完毕,time:1521037864652
Thread:pool-1-thread-6准备完毕,time:1521037864652
Thread:pool-1-thread-5准备完毕,time:1521037864652
Thread:pool-1-thread-4准备完毕,time:1521037864652
Thread:pool-1-thread-9准备完毕,time:1521037864652
Thread:pool-1-thread-8准备完毕,time:1521037864652
从结果看，线程几乎是同时执行的。
二是用CountDownLatch 实现，CountDownLatch可以理解为一个计数器，直到计数器为0了，等待的线程才执行。
public class testCountDownLatch
{
CountDownLatch countDownLatch = new CountDownLatch(1);
private void runThread()
{
ExecutorService executorService = Executors.newFixedThreadPool(10);
for (int i = 0; i < 10; i++)
{
try
{
Thread.sleep(100);
}
catch (InterruptedException e)
{
e.printStackTrace();
}
executorService.submit(new Runnable()
{
@Override
public void run()
{
try
{
countDownLatch.await();
System.out.println("Thread:" + Thread.currentThread()
.getName() + ",time: " + System.currentTimeMillis());
}
catch (InterruptedException e)
{
e.printStackTrace();
}
}
});
}
countDownLatch.countDown();
}
public static void main(String[] args)
{
testCountDownLatch test = new testCountDownLatch();
test.runThread();
}
}从执行结果看，线程也几乎同时进行的：
Thread:pool-1-thread-2,time: 1521038129807
Thread:pool-1-thread-3,time: 1521038129807
Thread:pool-1-thread-1,time: 1521038129807
Thread:pool-1-thread-4,time: 1521038129807
Thread:pool-1-thread-6,time: 1521038129807
Thread:pool-1-thread-5,time: 1521038129807
Thread:pool-1-thread-9,time: 1521038129807
Thread:pool-1-thread-8,time: 1521038129807
Thread:pool-1-thread-7,time: 1521038129807
Thread:pool-1-thread-10,time: 1521038129807
其他自己用wait和notify实现。
java程序同时执行的话，可以利用以上的两个方法去执行，当然具体实施哪种方法，大家可以根据自己需求去选择!最后大家如果想要了解更多java实例知识，敬请关注奇Q工具网。
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