題目：

方法1：（有問題）

package com.gao.Project.Pro9;

public class Product {//商品類
    //品牌
    private String brand;
    //名字
    private String name;

    public String getBrand() {
        return brand;
    }

    public void setBrand(String brand) {
        this.brand = brand;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

package com.gao.Project.Pro9;

public class PuoducerThread extends Thread{ //生產者線程
    //共享商品
    private Product p ;
    //構造器
    public PuoducerThread(Product p) {
        this.p = p;
    }

    @Override
    public void run() {
        for (int i = 1; i <= 10 ; i++) {//生產10個商品   i--->生產次數
            synchronized (p){
                if(i%2 == 0){
                    //生成費列羅巧克力
                    p.setBrand("費列羅");
                    p.setName("巧克力");
                    try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                        throw new RuntimeException(e);
                    }
                }else {
                    //生產哈爾濱啤酒
                    p.setBrand("哈爾濱");
                    p.setName("啤酒");
                    try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                        throw new RuntimeException(e);
                    }
                }
            }
            //將生產的產品打印出來
            System.out.println("生產者生產了"+p.getBrand()+"---"+p.getName());
        }
    }
}

package com.gao.Project.Pro9;

public class CustomerThread extends Thread{//消費者線程
    //共享商品
    private Product p;

    public CustomerThread(Product p) {
        this.p = p;
    }

    @Override
    public void run() {
        for (int i = 1; i <=10 ; i++) {// 消費次數
           synchronized (p){//用同一個鎖鎖住，解決同步問題-->防止數據錯亂--->費列羅啤酒，哈爾濱巧克力
               System.out.println("消費者消費了"+p.getBrand()+"---"+p.getName());
           }
        }
    }
}

package com.gao.Project.Pro9;

public class Test {
    public static void main(String[] args) {
        //共享的商品
        Product p = new Product();
        //創建生產者和消費者線程
        PuoducerThread pt = new PuoducerThread(p);
        CustomerThread ct = new CustomerThread(p);
        pt.start();
        ct.start();
    }
}

方法2：(同步)

package com.gao.Project.Pro10;

public class PuoducerThread extends Thread{ //生產者線程
    //共享商品
    private Product p ;
    //構造器
    public PuoducerThread(Product p) {
        this.p = p;
    }

    @Override
    public void run() {
        for (int i = 1; i <= 10 ; i++) {//生產10個商品   i--->生產次數
            if(i % 2 == 0){
                p.setProduct("費列羅","巧克力");
            }else {
                p.setProduct("哈爾濱","啤酒");

            }

        }
    }
}

package com.gao.Project.Pro10;

public class CustomerThread extends Thread{//消費者線程
    //共享商品
    private Product p;

    public CustomerThread(Product p) {
        this.p = p;
    }

    @Override
    public void run() {
        for (int i = 1; i <=10 ; i++) {// 消費次數
            p.getProduct();
           }
      }
}

package com.gao.Project.Pro10;

public class Product {//商品類
    //品牌
    private String brand;
    //名字
    private String name;

    //引入一個燈    ture:紅燈   false:綠燈
    boolean flag = false;  //默認情況沒有商品，生產者得生產了之后才能消費

    public String getBrand() {
        return brand;
    }

    public void setBrand(String brand) {
        this.brand = brand;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }


    //生產商品
    public synchronized void setProduct(String brand,String name){
        if(flag == true){//燈是紅的，證明有商品，生產者不生產，等待消費者消費
            try {
                wait();  //出現異常，用try catch 捕獲
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        }
        //燈是綠的，證明沒有商品，就生產
            this.setBrand(brand);
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
            this.setName(name);

        //將生產的產品打印出來
        System.out.println("生產者生產了"+this.getBrand()+"---"+this.getName());

        //生產完以后，燈變色
        flag = true;
        //告訴消費者來消費
        notify();
    }

    //消費商品
    public synchronized void getProduct (){
        if(!flag){//(flag == false) 燈是綠的，證明沒有商品，消費者需要等待
            try {
                wait();
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        }
        //燈是紅的，證明有商品，可以消費
        System.out.println("消費者消費了"+this.getBrand()+"---"+this.getName());
        //消費完，燈變色
        flag = false;
        //告訴生產者趕緊生產
        notify();
    }
}

package com.gao.Project.Pro10;

public class Test {
    public static void main(String[] args) {
        //共享的商品
        Product p = new Product();
        //創建生產者和消費者線程
        PuoducerThread pt = new PuoducerThread(p);
        CustomerThread ct = new CustomerThread(p);
        pt.start();
        ct.start();
    }
}