简单工厂，工厂方法和抽象工厂模式

1，简单工厂模式：将创建类实例的过程封装到工厂类的方法中。

2，工厂方法：处了将创建类实例封装到一个工厂类外，还将类的实例化推迟到子类。用于当用户想得到某一种产品的类型时。比如，有一系列的飞机类，战斗机，运输机等，用户通过工厂可以得到某一个所需要的某个飞机类型，但是通过使用接口（抽象类），飞机类型的实例真正创建是在工厂类（接口）的子类（实现类）中完成的。这就是所谓的“实例化推迟到子类”。 planefactory.h 1 2 class Plane; 3 class PlaneFactory 4 { 5 private: 6 public: 7 PlaneFactory(); 8 virtual Plane* getPlane()=0; 9 virtual ~PlaneFactory(); 10 11 }; 12 class FightPlaneFactory:public PlaneFactory 13 { 14 public: 15 FightPlaneFactory(); 16 ~FightPlaneFactory(); 17 Plane* getPlane(); 18 private: 19 Plane *plane; 20 }; 21 class TransportPlaneFactory:public PlaneFactory 22 { 23 public: 24 TransportPlaneFactory(); 25 Plane* getPlane(); 26 ~TransportPlaneFactory(); 27 private: 28 Plane *plane; 29 }; plane.h 1 #include <iostream> 2 using namespace std; 3 #include <string> 4 class Plane 5 { 6 private: 7 int length; 8 int num; 9 string name; 10 public: 11 void setName(string name); 12 string getName(); 13 virtual void show(){} 14 }; 15 class FightPlane:public Plane 16 { 17 public: 18 void show(); 19 }; 20 class TransportPlane:public Plane 21 { 22 public: 23 void show(); 24 }; ~ ~ main.cpp 1 #include "plane.h" 2 #include "planefactory.h" 3 4 int main() 5 { 6 PlaneFactory *factory =new FightPlaneFactory; 7 Plane *plane = factory->getPlane(); 8 plane->show(); 9 delete plane; 10 } ~

3，抽象工厂：和前面提到的工厂方法比较（用户创建某一种产品的不同类型），抽象工厂为创建多种产品（飞机，坦克，舰船等）提供了接口。实际上，抽象工厂是工厂方法的累加，而工厂方法是抽象工厂的特列。当增加产品种类需要对工厂方法进行扩展，使得工厂类能够创建多种产品，对应每一个工厂类的子类都能创建不同的产品，但每个子类可以根据“同种产品的不同类型”，实际创建出不同的产品类型，例如可以创建战斗机和运输机，陆上坦克和水上坦克等。 abstract_factory.h 1 class Plane; 2 class Tanker; 3 class AbstractFactory 4 { 5 private: 6 public: 7 AbstractFactory(); 8 virtual Plane* getPlane()=0; 9 virtual Tanker* getTanker()=0; 10 virtual ~AbstractFactory(); 11 12 }; 13 class AbstractFactory1:public AbstractFactory 14 { 15 public: 16 AbstractFactory1(); 17 ~AbstractFactory1(); 18 Plane* getPlane(); 19 Tanker* getTanker(); 20 private: 21 }; 22 class AbstractFactory2:public AbstractFactory 23 { 24 public: 25 AbstractFactory2(); 26 ~AbstractFactory2(); 27 Plane* getPlane(); 28 Tanker* getTanker(); 29 private: 30 }; tanker.h 1 #include <iostream> 2 using namespace std; 3 #include <string> 4 class Tanker 5 { 6 public: 7 Tanker(); 8 virtual ~Tanker()=0; 9 virtual void show()=0; 10 private: 11 string name; 12 int num; 13 }; 14 class GroundTanker:public Tanker 15 { 16 public: 17 GroundTanker(); 18 void show(); 19 ~GroundTanker(); 20 }; 21 class SeaTanker:public Tanker 22 { 23 public: 24 SeaTanker(); 25 void show(); 26 ~SeaTanker(); 27 }; plane.h 1 #include <iostream> 2 using namespace std; 3 #include <string> 4 class Plane 5 { 6 private: 7 int length; 8 int num; 9 string name; 10 public: 11 void setName(string name); 12 string getName(); 13 virtual void show(){} 14 }; 15 class FightPlane:public Plane 16 { 17 public: 18 void show(); 19 }; 20 class TransportPlane:public Plane 21 { 22 public: 23 void show(); 24 }; main.cpp 1 #include "plane.h" 2 #include "tanker.h" 3 #include "abstract_factory.h" 4 5 int main() 6 { 7 AbstractFactory *factory =new AbstractFactory1; 8 Plane *plane = factory->getPlane(); 9 plane->show(); 10 delete plane; 11 Tanker *tanker = factory->getTanker(); 12 tanker->show(); 13 delete tanker; 14 }