多线程实现生产者消费者，堆积满 100 后停止生产，消费到小于 50 后继续生产
这是一种写法，但是我觉得不太好：
- 它通过循环创建了很多的线程，每个线程只消费/生产一次
- 它使用
notifyAll()通知所有的线程唤醒，包括生产者和消费者，感觉产品数量永远也达不到 50
public class Producer implements Runnable {
private final Queue<Product> queue;
private final int maxCapacity;
public Producer(Queue<Product> queue, int maxCapacity) {
this.queue = queue;
this.maxCapacity = maxCapacity;
}
@Override
public void run() {
synchronized (queue) {
while (queue.size() == maxCapacity) { //一定要用 while，而不是 if，下文解释
try {
System.out.println("生产者" + Thread.currentThread().getName() + "等待中... Queue 已达到最大容量，无法生产");
queue.wait();
System.out.println("生产者" + Thread.currentThread().getName() + "退出等待");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
int i = new Random().nextInt();
queue.offer(new Product("产品" + i));
System.out.println("生产者" + Thread.currentThread().getName() + "生产了产品：" + i);
queue.notifyAll();// 通知消费者消费
}
}
}
public class Consumer implements Runnable {
private final Queue<Product> queue;
private final int minCapacity;
public Consumer(Queue<Product> queue, int minCapacity) {
this.queue = queue;
this.minCapacity = minCapacity;
}
@Override
public void run() {
synchronized (queue) {
while (queue.isEmpty()) {
try {
System.out.println("消费者" + Thread.currentThread().getName() + "等待中... Queue 已缺货，无法消费");
queue.wait();
System.out.println("消费者" + Thread.currentThread().getName() + "退出等待");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
Product product = queue.poll();
System.out.println("消费者" + Thread.currentThread().getName() + "消费了：" + product.getName());
if (queue.size() < minCapacity) queue.notifyAll();// 库存小于50，通知生产者生产
}
}
}
public static void main(String[] args) {
Queue<Product> queue = new ArrayDeque<>();
for (int i = 0; i < 100; i++) {
new Thread(new Producer(queue, 100)).start();
new Thread(new Consumer(queue, 50)).start();
}
}