1.1 示例描述
小朋友过生日: 要点燃N根蜡烛(N个线程), 才能唱生日歌(末尾的任务);
- (1). 然而每个蜡烛都要点, 都是一个线程; countDown 减1
- (2). N个蜡烛点燃后; 才能唱生日歌:main线程; countDown 减到0了, 才能破除await, 唱歌吃蛋糕!
1.2 示例代码
import lombok.extern.slf4j.Slf4j;
import java.util.Random;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
/**
* @Author weijun.nie
* @Date 2020/4/20 15:11
* @Version 1.0
*/
@Slf4j
public class CountDownLatchCelebrateBirthday {
public static void main(String[] args) throws InterruptedException {
final int AGE = 10;
CountDownLatch cdl = new CountDownLatch(AGE);
/**
* 给小朋友过生日, 小朋友N岁
*/
ExecutorService exec = Executors.newCachedThreadPool();
for (int i = 0; i < AGE; i++) {
int finalI = i;
exec.submit(() -> {
try {
Thread.currentThread().setName("[生日蜡烛第" + finalI + "个]");
// 让main线程先走起;
Thread.sleep(500);
String name = Thread.currentThread().getName();
log.info("点亮{}, 激动的心, 颤抖的手, 燃亮的火柴, 可爱的蜡烛 ,插向蛋糕~", name);
long time = new Random().nextInt(10) * 1000;
Thread.sleep(time);
log.info("{} 点燃并插到蛋糕上了......耗时{} ms", name, time);
cdl.countDown();
} catch (InterruptedException e) {
e.printStackTrace();
}
});
}
exec.shutdown();
log.info("蛋糕摆放好, 等着插蜡烛呢....");
cdl.await();
log.info("所有蜡烛都点亮并插上了..一起唱:祝你生日快乐......");
}
}1.3 结果输出
console:
15:41:57.353 [main] INFO CountDownLatchCelebrateBirthday - 蛋糕摆放好, 等着插蜡烛呢….
15:41:57.857 [[生日蜡烛第1个]] INFO CountDownLatchCelebrateBirthday - 点亮[生日蜡烛第1个], 激动的心, 颤抖的手, 燃亮的火柴, 可爱的蜡烛 ,插向蛋糕~
15:41:57.860 [[生日蜡烛第0个]] INFO CountDownLatchCelebrateBirthday - 点亮[生日蜡烛第0个], 激动的心, 颤抖的手, 燃亮的火柴, 可爱的蜡烛 ,插向蛋糕~
15:41:57.861 [[生日蜡烛第9个]] INFO CountDownLatchCelebrateBirthday - 点亮[生日蜡烛第9个], 激动的心, 颤抖的手, 燃亮的火柴, 可爱的蜡烛 ,插向蛋糕~
15:41:57.861 [[生日蜡烛第8个]] INFO CountDownLatchCelebrateBirthday - 点亮[生日蜡烛第8个], 激动的心, 颤抖的手, 燃亮的火柴, 可爱的蜡烛 ,插向蛋糕~
15:41:57.861 [[生日蜡烛第7个]] INFO CountDownLatchCelebrateBirthday - 点亮[生日蜡烛第7个], 激动的心, 颤抖的手, 燃亮的火柴, 可爱的蜡烛 ,插向蛋糕~
15:41:57.861 [[生日蜡烛第6个]] INFO CountDownLatchCelebrateBirthday - 点亮[生日蜡烛第6个], 激动的心, 颤抖的手, 燃亮的火柴, 可爱的蜡烛 ,插向蛋糕~
15:41:57.861 [[生日蜡烛第5个]] INFO CountDownLatchCelebrateBirthday - 点亮[生日蜡烛第5个], 激动的心, 颤抖的手, 燃亮的火柴, 可爱的蜡烛 ,插向蛋糕~
15:41:57.861 [[生日蜡烛第4个]] INFO CountDownLatchCelebrateBirthday - 点亮[生日蜡烛第4个], 激动的心, 颤抖的手, 燃亮的火柴, 可爱的蜡烛 ,插向蛋糕~
15:41:57.861 [[生日蜡烛第3个]] INFO CountDownLatchCelebrateBirthday - 点亮[生日蜡烛第3个], 激动的心, 颤抖的手, 燃亮的火柴, 可爱的蜡烛 ,插向蛋糕~
15:41:57.861 [[生日蜡烛第2个]] INFO CountDownLatchCelebrateBirthday - 点亮[生日蜡烛第2个], 激动的心, 颤抖的手, 燃亮的火柴, 可爱的蜡烛 ,插向蛋糕~
15:41:57.861 [[生日蜡烛第8个]] INFO CountDownLatchCelebrateBirthday - [生日蜡烛第8个] 点燃并插到蛋糕上了……耗时0 ms
15:42:01.862 [[生日蜡烛第5个]] INFO CountDownLatchCelebrateBirthday - [生日蜡烛第5个] 点燃并插到蛋糕上了……耗时4000 ms
15:42:01.862 [[生日蜡烛第9个]] INFO CountDownLatchCelebrateBirthday - [生日蜡烛第9个] 点燃并插到蛋糕上了……耗时4000 ms
15:42:04.862 [[生日蜡烛第4个]] INFO CountDownLatchCelebrateBirthday - [生日蜡烛第4个] 点燃并插到蛋糕上了……耗时7000 ms
15:42:05.861 [[生日蜡烛第3个]] INFO CountDownLatchCelebrateBirthday - [生日蜡烛第3个] 点燃并插到蛋糕上了……耗时8000 ms
15:42:05.861 [[生日蜡烛第0个]] INFO CountDownLatchCelebrateBirthday - [生日蜡烛第0个] 点燃并插到蛋糕上了……耗时8000 ms
15:42:05.861 [[生日蜡烛第1个]] INFO CountDownLatchCelebrateBirthday - [生日蜡烛第1个] 点燃并插到蛋糕上了……耗时8000 ms
15:42:05.861 [[生日蜡烛第2个]] INFO CountDownLatchCelebrateBirthday - [生日蜡烛第2个] 点燃并插到蛋糕上了……耗时8000 ms
15:42:06.861 [[生日蜡烛第7个]] INFO CountDownLatchCelebrateBirthday - [生日蜡烛第7个] 点燃并插到蛋糕上了……耗时9000 ms
15:42:06.861 [[生日蜡烛第6个]] INFO CountDownLatchCelebrateBirthday - [生日蜡烛第6个] 点燃并插到蛋糕上了……耗时9000 ms
15:42:06.861 [main] INFO CountDownLatchCelebrateBirthday - 所有蜡烛都点亮并插上了..一起唱:祝你生日快乐……
转载请注明来源，欢迎对文章中的引用来源进行考证，欢迎指出任何有错误或不够清晰的表达。可以在下面评论区评论，也可以邮件至 hi@niewj.com
