假设5个人要去厕所，只有2个位置。代码：

@Slf4j
public class WashRoom implements Runnable {private int n; // 用来记录第几个人@Overridepublic void run() {try {log.info(n+" 开始");int milliSecond = RandomUtils.createMilliSecond(1, 4); // 这里只要是随机秒数就行Thread.sleep(milliSecond);log.info(n +"结束，用时： "+milliSecond);} catch (InterruptedException e) {e.printStackTrace();}}public WashRoom(int n){this.n=n;}public static void main(String[] args) {ExecutorService executorService = Executors.newFixedThreadPool(2);for (int i = 0; i < 5; i++) {  // 5个人上厕所，只有2个位置executorService.execute(new WashRoom(i));}executorService.shutdown(); // 别忘了关闭}
}