1，仓库类
public class WareHouse {

    private ArrayList<String>  list = new ArrayList<>();

    private Integer i = 0;
    /**
     * 向集合中添加元素
     */
    public synchronized String add(){
        if(list.size()<20){
            list.add(i+++"");
        }else{
            //return;
            try {
                this.notifyAll();//唤醒全部线程，可根据设置的优先级唤醒顺序
                this.wait();//进入等待（阻塞）
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        if(list.size()>0){
            return list.get(list.size()-1);
        }else{
            return "";
        }
    }

    /**
     * 从集合中取出元素
     */
    public synchronized String get(){
        String name = "";
        if(list.size()>0){
            name = list.remove(0);
        }else{
            //return;
            try {
                this.notifyAll();//唤醒全部线程，可根据设置的优先级唤醒顺序
                this.wait();//进入等待（阻塞）
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        return name;
    }
}

2，消费者类

public class Consumer extends Thread{

    private String name;

    private WareHouse house;


    public Consumer(String name,WareHouse house){
        this.name = name;
        this.house = house;
    }

    public void run(){
        String houseName = null;
        while(true){
            houseName = house.get();
            System.out.println(this.name+"拿走了一件货物。。"+houseName);
            try {
                this.sleep(400);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}
3，生产者类

public class Producer extends Thread{

    private String name;

    private WareHouse house;

    public Producer(String name,WareHouse house){
        this.name = name;
        this.house = house;
    }

    public void run(){
        String houseName = null;
        while(true){
            houseName = house.add();
            System.out.println(this.name+"生产了一件货物。。"+houseName);
            try {
                this.sleep(200);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

}