经典例题：生产者/消费者问题

蔚落 2023-10-13 09:58 69阅读 0赞

生产者(Productor)将产品放在柜台(Counter)，而消费者(Customer)从柜台  
处取走产品，生产者一次只能生产固定数量的产品(比如:1）， 这时柜台中不能  
再放产品,此时生产者应停止生产等待消费者拿走产品,此时生产者唤醒消费者来  
取走产品,消费者拿走产品后,唤醒生产者,消费者开始等待.

package 生产与消费;
    
    public class Counter {
         int num=0;
    
        public synchronized void add(){
            if(num==0){
                num=1;
                this.notify();//唤醒消费者进程
                System.out.println("生产者生产了一件商品");
            }else {
                try {
                    this.wait();//生产者线程等待
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
    
        }
        public synchronized void sub(){
            if(num==1){
                num=0;
                this.notify();//唤醒生产者进程
                System.out.println("消费者消费了一件商品");
            }else {
                try {
                    this.wait();//消费者线程等待
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    
    }

package 生产与消费;
    
    public class ProductThread extends Thread{
        Counter counter;
    
        public ProductThread(Counter counter) {
            this.counter = counter;
        }
    
        @Override
        public void run() {
            while (true){
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                counter.add();
            }
        }
    }

package 生产与消费;
    
    public class ConsumeThread extends Thread{
        Counter counter;
    
        public ConsumeThread(Counter counter) {
            this.counter = counter;
        }
        public void run() {
            while (true){
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                counter.sub();
            }
        }
    }

package 生产与消费;
    
    public class Test {
        public static void main(String[] args) {
            Counter counter=new Counter();
            ProductThread productThread=new ProductThread(counter);
            ConsumeThread consumeThread=new ConsumeThread(counter);
            productThread.start();
            consumeThread.start();
        }
    
    
    }