设计模式——工厂模式

工厂模式

1.需求

抽奖活动

新用户注册即参与抽奖，奖品为：1.优惠券，2.优酷会员，3.京东卡

2.无模式

public class FreeGoodsController{public Result<?> send(AwardInfo awardInfo){int awardType = awardInfo.getAwardType();if(awardType == 1){DiscountService discountService = new DiscountService();discountService.send();return Result.success();}if(awardType == 2){YouKuService youkuService = new YouKuService;youkuService.send();return Result.success();}if(awardType == 3){JDService jdService = new JDService();jdService.send();return Result.success();}return Result.failed();}}

3.简单工厂模式

简单工厂模式包含以下特征：

• 抽象产品
• 具体产品
• 具体工厂

3.1抽象产品

public interface IFreeGoods{boolean send();
}

3.2具体产品

public class DiscountService implements IFreeGoods{public boolean send(){System.out.println("发放打折券");return true;}
}

public class YouKuService implements IFreeGoods{public boolean send(){System.out.println("发放优酷会员");return true;}
}

public class JDCardService implements IFreeGoods{public boolean send(){System.out.println("发放京东卡");return true;}
}

3.3具体工厂

public class FreeGoodsServiceFactory{public static IFreeGoods getInstance(Integer awardType){if(awardType == 1){return new DiscountService();}if(awardType == 2){return new YouKuService();}if(awardType == 3){return new JDCardService();}return null;}
}

public class FreeGoodsController{public Result<?> send(AwardInfo awardInfo){int awardType = awardInfo.getAwardType();IFreeGoods freeGoods = FreeGoodsFServiceFactory.getInstance(awardType);if(freeGoods.send()){return Result.success();}else {return Result.failed();}}}

4.工厂方法模式

• 抽象产品
• 具体产品
• 抽象工厂
• 具体工厂

4.1抽象产品——定义产品的行为

public interface IFreeGoods{boolean send();
}

4.2具体产品——实现或继承抽象产品的子类

public DiscountFreeGoods implements IFreeGoods{public boolean send(){System.out.println("发放打折券");return true;}
}

public YouKuFreeGoods implements IFreeGoods{public boolean send(){System.out.println("发放优酷会员");return true;}
}

public JDFreeGoods implements IFreeGoods{public boolean send(){System.out.println("发放京东卡");return true;}
}

4.3抽象工厂——提供创建产品的接口

public interface FreeGoodsFactory{IFreeGoods createFreeGoods();
}

4.4具体工厂

public class DiscountFreeGoodsFactory implements FreeGoodsFacotry{public IFreeGoods createFreeGoods(){return new DiscountFreeGoods();}
}

public class YouKuFreeGoodsFactory implements FreeGoodsFacotry{public IFreeGoods createFreeGoods(){return new YoukuFreeGoods();}
}

public class JDFreeGoodsFactory implements FreeGoodsFacotry{public IFreeGoods createFreeGoods(){return new JDFreeGoods();}
}

5.抽象工厂模式

基于上述拉新人注册的需求进行扩展

之前是的奖品为：平台的打折券、优酷的月卡、京东的小礼品

现在的奖品为：平台的打折券、平台的会员卡，优酷的月卡打折券、优酷的月卡，京东的商品打折券、京东会员卡

由现在的需求可以看出，打折券、会员卡可以归为一类，奖品提供方可以归为另一类

打折券发放以后可以购买相关平台的指定商品

会员卡发放以后需要绑定相关平台的用户账户

由此引出了产品族以及产品等级结构的概念

5.1产品等级结构

产品等级结构即产品的继承结构，如一个抽象类是打折券，其子类有平台的打折券、优酷的打折券、京东的打折券；

5.2产品族

产品族是指由同一个工厂生产的，位于不同产品等级结构中的一组产品，比如平台的工厂生产平台的打折券，生产平台的会员卡

5.3抽象工厂模式的具体特征

• 抽象产品（产品等级结构父类）
• 具体产品（产品等级结构子类）
• 抽象工厂（产品族父类）
• 具体工厂（产品族子类）

5.4抽象产品

public interface IFreeGoods{boolean send();
}

public abstract class DiscountFreeGoods extends IFreeGoods{// 获取售卖的商品List getSaleList();// 计算价格BigDecimal calc(BigDecimal price);
}

public abstract class VipCardFreeGoods extends IFreeGoods {boolean bindAccount(Long phoneNumber);
}

5.5抽象工厂

public interface FreeGoodsFactory{DiscountFreeGoods createDiscountFreeGoods();VipCardFreeGoods createVipCardFreeGoods();
}

5.6具体产品

5.6.1打折券的具体实现

public class PlatformDiscountFreeGoods extends DiscountFreeGoods {public boolean send(){System.out.println("发放平台打折券");}public List getSaleList(){// 这里返回平台售卖的商品}public BigDecimal calc(BigDecimal price){// 这里计算平台打折券使用后的优惠价格}
}

public class YoukuDiscountFreeGoods extends DiscountFreeGoods {public boolean send(){System.out.println("发放优酷打折券");}public List getSaleList(){// 这里调用优酷的接口返回优酷售卖的商品}public BigDecimal calc(BigDecimal price){// 这里调用用户的接口计算打折券使用后的优惠价格}
}

public class JDDiscountFreeGoods extends DisCountFreeGoods {public boolean send(){System.out.println("发放京东打折券");}public List getSaleList(){// 这里调用京东的接口返回京东售卖的商品}public BigDecimal calc(BigDecimal price){// 这里调用京东的接口计算打折券使用后的优惠价格}
}

5.6.2会员卡的具体实现

public class PlatformVipCardFreeGoods extends VipCardFreeGoods {public boolean send(){System.out.println("发放京东会员卡");}public boolean bindAccount(Long phoneNumber) {// 这里绑定平台账号}
}

public class YouKuVipCardFreeGoods extends VipCardFreeGoods {public boolean send(){System.out.println("发放京东会员卡");}public boolean bindAccount(Long phoneNumber) {// 这里调用优酷的接口，传手机号过去绑定用户账号}
}

public class JDVipCardFreeGoods extends VipCardFreeGoods {public boolean send(){System.out.println("发放京东会员卡");}public boolean bindAccount(Long phoneNumber) {// 这里调用京东的接口，传手机号过去绑定用户账号}
}

5.7具体工厂

public class PlatformFreeGoodsFactory implements FreeGoodsFactory {public DiscountFreeGoods createFreeGoods(){return new PlatformDiscountFreeGoods();}public VipCardFreeGoods createVipCardFreeGoods(){return new PlatformVipCardFreeGoods();}
}

public class YouKuFreeGoodsFactory implements FreeGoodsFactory {public DiscountFreeGoods createFreeGoods(){return new YoukuDiscountFreeGoods();}public VipCardFreeGoods createVipCardFreeGoods(){return new YouKuVipCardFreeGoods();}
}

public class JDFreeGoodsFactory implements FreeGoodsFactory {public DiscountFreeGoods createFreeGoods(){return new JDDiscountFreeGoods();}public VipCardFreeGoods createVipCardFreeGoods(){return new JDVipCardFreeGoods();}
}

5.8调用

public class Client {private DiscountFreeGoods discountFreeGoods;private VipCardFreeGoods vipCardFreeGoods;public Client(FreeGoodsFactory factory){this.discountFreeGoods = factory.createDiscountFreeGoods();this.vipCardFreeGoods = factory.createVipCardFreeGoods();}// 省略 get和set
}