Java 多线程-生产者、消费者

一、整体代码

        ThreadDemo.java

 

public  class ThreadDemo { 

        public static void main(String[] args) { 

                Godown godown = new Godown(0); 

                Consumer c1 = new Consumer(50, godown); 

                Consumer c2 = new Consumer(20, godown); 

                Consumer c3 = new Consumer(30, godown); 

                Producer p1 = new Producer(10, godown); 

                Producer p2 = new Producer(10, godown); 

                Producer p3 = new Producer(10, godown); 

                Producer p4 = new Producer(10, godown); 

                Producer p5 = new Producer(10, godown); 

                Producer p6 = new Producer(10, godown); 

                Producer p7 = new Producer(80, godown); 



                c1.start(); 

                c2.start(); 

                c3.start(); 

                p1.start(); 

                p2.start(); 

                p3.start(); 

                p4.start(); 

                p5.start(); 

                p6.start(); 

                p7.start(); 

        } 

} 



/** 

* 仓库 

*/ 

class Godown { 

        public static final int max_size = 100; //最大库存量 

        public int curnum;     //当前库存量 



        Godown() { 

        } 



        Godown(int curnum) { 

                this.curnum = curnum; 

        } 



        /** 

         * 生产指定数量的产品 

         * 

         * @param neednum 

         */ 

        public synchronized void produce(int neednum) { 

                //测试是否需要生产 

                while (neednum + curnum > max_size) { 

                        System.out.println("要生产的产品数量" + neednum + "超过剩余库存量" + (max_size - curnum) + "，暂时不能执行生产任务!"); 

                        try { 

                                //当前的生产线程等待 

                                wait(); 

                        } catch (InterruptedException e) { 

                                e.printStackTrace(); 

                        } 

                } 

                //满足生产条件，则进行生产，这里简单的更改当前库存量 

                curnum += neednum; 

                System.out.println("已经生产了" + neednum + "个产品，现仓储量为" + curnum); 

                //唤醒在此对象监视器上等待的所有线程 

                notifyAll(); 

        } 



        /** 

         * 消费指定数量的产品 

         * 

         * @param neednum 

         */ 

        public synchronized void consume(int neednum) { 

                //测试是否可消费 

                while (curnum < neednum) { 

                        try { 

                                //当前的生产线程等待 

                                wait(); 

                        } catch (InterruptedException e) { 

                                e.printStackTrace(); 

                        } 

                } 

                //满足消费条件，则进行消费，这里简单的更改当前库存量 

                curnum -= neednum; 

                System.out.println("已经消费了" + neednum + "个产品，现仓储量为" + curnum); 

                //唤醒在此对象监视器上等待的所有线程 

                notifyAll(); 

        } 

} 



/** 

* 生产者 

*/ 

class Producer extends Thread { 

        private int neednum;                //生产产品的数量 

        private Godown godown;            //仓库 



        Producer(int neednum, Godown godown) { 

                this.neednum = neednum; 

                this.godown = godown; 

        } 



        public void run() { 

                //生产指定数量的产品 

                godown.produce(neednum); 

        } 

} 



/** 

* 消费者 

*/ 

class Consumer extends Thread { 

        private int neednum;                //生产产品的数量 

        private Godown godown;            //仓库 



        Consumer(int neednum, Godown godown) { 

                this.neednum = neednum; 

                this.godown = godown; 

        } 



        public void run() { 

                //消费指定数量的产品 

                godown.consume(neednum); 

        } 

}

 

 

二、解释