Java主线程等候子线程执行完毕-CountDownLatch

Java主线程等待子线程执行完毕-CountDownLatch

主线程：

?

1. //Main主线程??
2. publicclassMainThread?{???
3. ???
4. ????publicstaticvoid?main(String[]?args)?throwsInterruptedException?{???
5. ????????longstartTime?=?System.currentTimeMillis();???
6. ????????intthreadNum?=?5;//线程数??
7. ????????//定义正在运行的线程数??
8. ????????CountDownLatch?runningThreadNum?=?newCountDownLatch(threadNum);??
9. ????????System.out.println(Thread.currentThread().getName()+"-start");??
10. ????????//创建多个子线程??
11. ????????for(inti?=?0;?i?<?threadNum;?i++)?{???
12. ????????????newSubThread(runningThreadNum).start();??
13. ????????}??
14. ????????//等待子线程都执行完了再执行主线程剩下的动作??
15. ????????runningThreadNum.await();??
16. ????????System.out.println(Thread.currentThread().getName()+"-end");??
17. ????????longendTime?=?System.currentTimeMillis();???
18. ????????System.out.println("runningTime:"+(endTime-startTime));??
19. ????}??
20. }??

子线程：

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1. //子线程??
2. publicclassSubThread?extendsThread{??
3. ???
4. ????//子线程记数器,记载着运行的线程数??
5. ????privateCountDownLatch?runningThreadNum;???
6. ???
7. ????publicSubThread(CountDownLatch?runningThreadNum){???
8. ????????this.runningThreadNum?=?runningThreadNum;???
9. ????}??
10. ???????
11. ????@Override??
12. ????publicvoidrun()?{???
13. ????????System.out.println(Thread.currentThread().getName()+"-start");??
14. ????????System.out.println(Thread.currentThread().getName()+"-do?something");??
15. ????????System.out.println(Thread.currentThread().getName()+"-end");??
16. ????????runningThreadNum.countDown();//正在运行的线程数减一??
17. ????}??
18. }??