JAVA生产者消费者(线程同步)代码学习示例

一、问题描述

生产者消费者问题是一个典型的线程同步问题。生产者生产商品放到容器中，容器有一定的容量（只能顺序放，先放后拿），消费者消费商品，当容器满了后，生产者等待，当容器为空时，消费者等待。当生产者将商品放入容器后，通知消费者；当消费者拿走商品后，通知生产者。

二、解决方案

对容器资源加锁，当取得锁后，才能对互斥资源进行操作。

public class producerconsumertest {

    public static void main(string []args){
        container con = new container();
        producer p = new producer(con);
        consumer c = new consumer(con);
        new thread(p).start();
        new thread(c).start();
    }

}

class goods{
    int id;
    public goods(int id){
        this.id=id;
    }

    public string tostring(){
        return "商品"+this.id;
    }
}

class container{//容器采用栈，先进后出
    private int index = 0;
    goods[] goods = new goods[6];

    public synchronized void push(goods good){
        while(index==goods.length){//当容器满了，生产者等待
            try {
                wait();
            } catch (interruptedexception e) {
                // todo auto-generated catch block
                e.printstacktrace();
            }
        }
        goods[index]=good;
        index++;
        notifyall();//当生产者放入商品后通知消费者
    }

    public synchronized goods pop(){
        while(index==0){//当容器内没有商品是等待
            try {
                wait();
            } catch (interruptedexception e) {
                // todo auto-generated catch block
                e.printstacktrace();
            }
        }
        index--;
        notifyall();//当消费者消费了商品后通知生产者
        return goods[index];
    }
}

class producer implements runnable{

    container con = new container();
    public producer(container con){
        this.con=con;
    }

    public void run(){
        for(int i=0; i<20; i++){
            goods good = new goods(i);
            con.push(good);
            system.out.println("生产了："+good);
            try {
                thread.sleep(100);
            } catch (interruptedexception e) {
                // todo auto-generated catch block
                e.printstacktrace();
            }
        }
    }

}

class consumer implements runnable{

    container con = new container();
    public consumer(container con){
        this.con=con;
    }

    public void run(){
        for(int i=0; i<20; i++){
            goods good=con.pop();
            system.out.println("消费了："+good);
            try {
                thread.sleep(1000);
            } catch (interruptedexception e) {
                // todo auto-generated catch block
                e.printstacktrace();
            }
        }
    }

   
}