生產者生產饅頭，消費者消費饅頭。一個籃子，生產者往籃子中放饅頭，消費者從籃子中取饅頭。

/**
 * 這是一個籃子類
 *
 * @author xcx
 * @time 2017年7月21日上午10:01:32
 */
public class Basket {
    // 籃子裏最多可以裝10個饅頭
    private final int Max_Numbers_StreamedBread = 10;
    SteamedBread[] sbBreads = new SteamedBread[Max_Numbers_StreamedBread];
    // 用來標記籃子中饅頭的數量
    private
 
 int index = 0;

    // 向籃子中放饅頭的方法
    public synchronized void push(SteamedBread sbBread) {
        while (index >= Max_Numbers_StreamedBread) {
            try {
                this.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        
 
this.notify();
        sbBreads[index] = sbBread;
        index++;

    }

    // 從籃子中拿饅頭的方法
    public synchronized SteamedBread pop() {
        while (index <= 0) {
            try {
                this.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            
 
return null;
        }
        this.notify();
        index--;
        return sbBreads[index];

    }

}

/**
 *消費者類
 *@author xcx 
 [email protected] 2017年7月21日上午10:23:53
 */
public class Consumer implements Runnable {
    Basket b = new Basket();
    private SteamedBread steamedBread;
    public Consumer(Basket b){
        this.b = b;        
    }

    @Override
    public void run() {
        for(int i=0;i<20;i++){
            steamedBread = b.pop();
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            if(steamedBread == null){
            }else{
                System.out.println("消費"+steamedBread);
            }
            
        }
            
        
    }

}

/**
 * 這是一個生產者類
 *
 * @author xcx
 * @time 2017年7月21日上午10:16:25
 */
public class Producer implements Runnable {
    private Basket b = new Basket();
    public Producer(Basket b){
        this.b = b;
    }
    @Override
    public void run() {
        for(int i=0;i<20;i++){
            SteamedBread sBread = new SteamedBread(i);
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("生產了第"+i+"個饅頭");
            b.push(sBread);
        }    
    }
}

/**
 *this is a class about SteamedBread
 *@author xcx 
 [email protected] 2017年7月21日上午9:59:16
 */
public class SteamedBread {
    private int i;
    public SteamedBread(int i){
        this.i = i;
    }
    
    @Override
    public String toString() {
        return "第"+i+"個饅頭";
    }

}

/**
 *同步線程測試類
 *@author xcx 
 [email protected] 2017年7月21日上午10:44:10
 */
public class Test {

    public static void main(String[] args) {
        //創建籃子的對象
        Basket basket = new Basket();
        //創建生產者線程和消費者線程
        Producer producer = new Producer(basket);
        Consumer consumer = new Consumer(basket);
        
        Thread t1 = new Thread(producer);
        Thread t2 = new Thread(consumer);
        
        t1.start();
        t2.start();
        

    }

}

Java學習（7）：同步問題之生產者與消費者的問題