java多線程示例 模擬生產者消費者

public class ProducerConsumer {


public static void main(String[] args) {
    SyncStack ss=new SyncStack();
    Producer pro=new Producer(ss);
    Consumer con=new Consumer(ss);
    new Thread(pro).start();
    new Thread(pro).start();
    new Thread(con).start();

}


}
class Product{
    int id;
    public Product(int id){
        this.id=id;
    }
    public String toString(){//重寫toString 方法，給pro加上編號，以便調試
        return "product   "+id;
    }
}
class SyncStack{//棧，先進后出
    Product[] proArr=new Product[6];//定義容器只能裝6件產品
    int index=0;
    public synchronized void push(Product pro){
        while(index==proArr.length){//當容器裝滿了產品，暫停生產
            try{
                this.wait();
            }catch(InterruptedException e){
                e.printStackTrace();
            }
        }
        this.notifyAll();//喚醒消費者消費
        proArr[index]=pro;
        index++;

}
public synchronized Product pop(){//同步，確保不被打斷
    while(index==0){//當容器里沒有產品可消費，暫停消費
        try{
            this.wait();
        }catch(InterruptedException e){
            e.printStackTrace();
        }
    }
    this.notifyAll();//喚醒生產者生產
    index--;
    return proArr[index];
}

}
class Producer implements Runnable{
    SyncStack ss=null;
    public Producer(SyncStack ss){
        this.ss=ss;
    }
    public void run() {
        for(int i=0;i<20;i++){
            Product pro=new Product(i);
            ss.push(pro);
            System.out.println("生產了:"+pro);
            try{//方便觀察結果，沒有實際意義
                Thread.sleep((int)(Math.random()200));
            }catch(InterruptedException e){
                e.printStackTrace();
            }
        }
    }
}
class Consumer implements Runnable{
    SyncStack ss=null;
    public Consumer(SyncStack ss){
        this.ss=ss;
    }
    public void run(){
        for(int i=0;i<20;i++){
            Product pro=ss.pop();
            System.out.println("消費了:"+pro);
            try{//方便觀察結果，沒有實際意義
                Thread.sleep((int)(Math.random()1000));
            }catch(InterruptedException e){
                e.printStackTrace();
            }
        }
    }
}
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