JAVA模拟三个老师同时给十个小朋友发礼品，每个老师相当于一个线程

好的，这是一个典型的生产者-消费者模型问题。我们可以使用 Java 中的多线程技术来实现。具体步骤如下：

1. 定义一个礼品类 Gift，包含礼品名称和礼品数量属性。

public class Gift {
    private String name;
    private int count;

    public Gift(String name, int count) {
        this.name = name;
        this.count = count;
    }

    public String getName() {
        return name;
    }

    public int getCount() {
        return count;
    }

    public void setCount(int count) {
        this.count = count;
    }
}

2. 定义一个礼品列表类 GiftList，包含一个 Gift 数组和一个计数器，用于统计礼品总数。

public class GiftList {
    private Gift[] gifts;
    private int count;

    public GiftList(int size) {
        gifts = new Gift[size];
        count = 0;
    }

    public synchronized boolean addGift(Gift gift) {
        if (count >= gifts.length) {
            return false;
        }
        gifts[count] = gift;
        count++;
        return true;
    }

    public int getCount() {
        return count;
    }
}

3. 定义一个生产者类 Teacher，代表一个老师。每个老师都有自己的礼品列表和礼品数量，可以向礼品列表中添加礼品。

public class Teacher implements Runnable {
    private String name;
    private GiftList giftList;
    private int giftCount;

    public Teacher(String name, GiftList giftList, int giftCount) {
        this.name = name;
        this.giftList = giftList;
        this.giftCount = giftCount;
    }

    public void run() {
        for (int i = 0; i < giftCount; i++) {
            Gift gift = new Gift(name + "的礼品" + (i + 1), 1);
            while (!giftList.addGift(gift)) {
                Thread.yield();
            }
            System.out.println(name + "发放了礼品" + (i + 1));
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

4. 定义一个消费者类 Child，代表一个小朋友。每个小朋友都从礼品列表中取出一件礼品，并将礼品数量减 1。

public class Child implements Runnable {
    private String name;
    private GiftList giftList;

    public Child(String name, GiftList giftList) {
        this.name = name;
        this.giftList = giftList;
    }

    public void run() {
        while (giftList.getCount() > 0) {
            Gift gift = null;
            synchronized (giftList) {
                if (giftList.getCount() > 0) {
                    gift = giftList.getGift();
                }
            }
            if (gift != null) {
                System.out.println(name + "收到了礼品：" + gift.getName());
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

5. 在主函数中创建三个 Teacher 实例和十个 Child 实例，并分别启动它们的线程。

public static void main(String[] args) {
    GiftList giftList = new GiftList(30);

    Thread[] teacherThreads = new Thread[3];
    for (int i = 0; i < teacherThreads.length; i++) {
        Teacher teacher = new Teacher("老师" + (i + 1), giftList, 10);
        teacherThreads[i] = new Thread(teacher);
        teacherThreads[i].start();
    }

    Thread[] childThreads = new Thread[10];
    for (int i = 0; i < childThreads.length; i++) {
        Child child = new Child("小朋友" + (i + 1), giftList);
        childThreads[i] = new Thread(child);
        childThreads[i].start();
    }
}

这样就可以模拟三个老师同时给十个小朋友发礼品的场景了。