importjava.util.concurrent.CountDownLatch;importorg.junit.Assert;importorg.junit.Test;/*** @Description: 规定线程次序的方法*/
public classThreadOrderTest {private long millisUnit = 1000;private int count = 2;classThreadOrder {/*** join方法使多个线程依次执行
*
*@return*@throwsInterruptedException*/
public long preserveOrderViaJoin() throwsInterruptedException {long startMillis =System.currentTimeMillis();
Thread tmp;for (int i = 0; i < count; i++) {
tmp= new Thread(newRunnable() {
@Overridepublic voidrun() {try{
Thread.sleep(millisUnit);
}catch(InterruptedException e) {
e.printStackTrace();
}
}
},"join-" +i);
tmp.start();
tmp.join();//不停地检测线程是否执行完成，执行完成才继续往下
}return System.currentTimeMillis() -startMillis;
}/*** CountdownLatch可同时阻塞多个线程，但它们可并发执行
*
*@return*@throwsInterruptedException*/
public long preserveOrderViaCountdownLatch() throwsInterruptedException {long startMillis =System.currentTimeMillis();final CountDownLatch countDownLatch = newCountDownLatch(count);for (int i = 0; i < count; i++) {new Thread(newRunnable() {
@Overridepublic voidrun() {try{
Thread.sleep(millisUnit);
}catch(InterruptedException e) {
e.printStackTrace();
}
countDownLatch.countDown();//只要计数器清零，等待的线程就可以开始执行，于是可以达到并发的效果
}
},"countDownLatch-" +i).start();
}
countDownLatch.await();return System.currentTimeMillis() -startMillis;
}
}
@Testpublic void testPreserveOrderViaJoin() throwsInterruptedException {
ThreadOrder threadOrder= newThreadOrder();
Assert.assertEquals(count, threadOrder.preserveOrderViaJoin()/millisUnit);
}
@Testpublic void testPreserveOrderViaCountdownLatch() throwsInterruptedException {
ThreadOrder threadOrder= newThreadOrder();
Assert.assertEquals(1, threadOrder.preserveOrderViaCountdownLatch() /millisUnit);
}
}
