CountDownLatch和枚舉配合使用

import java.util.concurrent.CountDownLatch;

public class CountDownLatchDemo {

    public static void main(String[] args) throws Exception {
        CountDownLatch countDownLatch = new CountDownLatch(6);
        for (int i = 1; i <= 6; i++) {
            new Thread(()->{
                System.out.println(Thread.currentThread().getName()+"\t 國，被滅");
                countDownLatch.countDown();
            },CountryEnum.forEach_CountryEnum(i).getRetMessage()).start();
        }
        countDownLatch.await();
        System.out.println(Thread.currentThread().getName()+"\t***秦帝國一統華夏");
    }

    public static void closeDoor() throws InterruptedException {
        CountDownLatch countDownLatch = new CountDownLatch(6);
        for (int i = 0; i <= 6; i++) {
            new Thread(() -> {
                System.out.println(Thread.currentThread().getName() + "\t上完自學，離開教室");
                countDownLatch.countDown();//減1
            }, String.valueOf(i)).start();
        }
        countDownLatch.await();
        System.out.println(Thread.currentThread().getName() + "\t****最後離開，關門");
    }
}      

　　枚舉：

import lombok.Getter;

public enum CountryEnum {
    ONE(1," 齊"),
    TWO(2,"楚"),
    THREE(3,"燕"),
    FOUR(4,"趙"),
    FIVE(5,"魏"),
    SIX(6,"韓");

    @Getter private Integer retCode;
    @Getter private String retMessage;

    CountryEnum(Integer retCode, String retMessage) {
        this.retCode = retCode;
        this.retMessage = retMessage;
    }

    public static CountryEnum forEach_CountryEnum(int index){
        CountryEnum[] myArray= CountryEnum.values();
        for(CountryEnum element: myArray){
            if(index==element.getRetCode()){
                return element;
            }
        }
        return null;
    }
}      

CountDownLatch 作用：讓一些線程阻塞，直到另一個線程完成一系列操作後才被喚醒      

CountDownLatch 主要有兩個方法，當一個活多個線程調用await方法時，調用線程會被阻塞。其他線程調用coutDown方法會将技術器減1（調用countDown方法的線程不會阻塞），
當計數器的值變為0時，因為調用await方法被阻塞的線程會被喚醒，繼續執行.