设计模式-工厂模式、抽象工厂模式-USB迷|专注于互联网分享

菜鸟教程：http://www.runoob/design-pattern/abstract-factory-pattern.html

一、工厂模式

1、概念：
是 Java 中最常用的设计模式之一。这种类型的设计模式属于创建型模式，它提供了一种创建对象的最佳方式。
在工厂模式中，我们在创建对象时不会对客户端暴露创建逻辑，并且是通过使用一个共同的接口来指向新创建的对象。
3、优点：扩展性强，当需要增加一个产品时，只需要增加一个具体实体类，还有修改一下工厂方法就行了，这样使得调用者不关心具体的实现。
4、缺点：工厂模式它的优点，同时也是它的缺点，增加一个产品，就要增加一个具体类，然后修改工厂方法，这样使得代码越来越复杂。
5、使用场景：

日志记录器：记录可能记录到本地硬盘、系统事件、远程服务器等，用户可以选择记录日志到什么地方。
数据库访问，当用户不知道最后系统采用哪一类数据库，以及数据库可能有变化时。
设计一个连接服务器的框架，需要三个协议，"POP3"、"IMAP"、"HTTP"，可以把这三个作为产品类，共同实现一个接口。

6、注意事项：作为一种创建类模式，在任何需要生成复杂对象的地方，都可以使用工厂方法模式。有一点需要注意的地方就是复杂对象适合使用工厂模式，而简单对象，特别是只需要通过 new 就可以完成创建的对象，无需使用工厂模式。如果使用工厂模式，就需要引入一个工厂类，会增加系统的复杂度
>>>案例
汽车工厂，传入车的类型，工厂返回一个具体车对象

1、Car

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public interface Car {
}

2、BmwCar

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class BmwCar implements Car{
}

3、JaguarCar

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class JaguarCar implements Car {
}

4、MercedesCar

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class MercedesCar  implements Car{
}

5、CarEnum

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public enum CarEnum {
    bmw("BMW"),
    jaguar("Jaguar"),
    mercedes("Mercedes");
    String carType;
    String desc;

    CarEnum(String carType) {
        this.carType = carType;
    }

}

6、CarFactoryMain

package factory;

import static factory.CarEnum.jaguar;

/**
 * Created by yanshao on 2019/1/4.
 */
public class CarFactoryMain {

    public static void main(String[] args) {
        Car car = getInstance(jaguar);
        System.out.println("您的汽车>>>"+car.getClass().getName());
    }
    public static Car getInstance(CarEnum carType){
        Car car = null;
        if(carType == null){
            return car;
        }
        switch (carType){
            case bmw:
                car = new BmwCar();
                break;
            case jaguar:
                car = new JaguarCar();
                break;
            case mercedes:
                car = new MercedesCar();
                break;
            default:
                return null;
        }
        return car;
    }

}

7、执行结果

您的汽车>>>factory.JaguarCar

二、抽象工厂模式

1、概念：

抽象工厂模式（Abstract Factory Pattern）是围绕一个超级工厂创建其他工厂。该超级工厂又称为其他工厂的工厂。这种类型的设计模式属于创建型模式，它提供了一种创建对象的最佳方式。在抽象工厂模式中，接口是负责创建一个相关对象的工厂，不需要显式指定它们的类。每个生成的工厂都能按照工厂模式提供对象。

2、优点：当一个产品族中的多个对象被设计成一起工作时，它能保证客户端始终只使用同一个产品族中的对象。

3：缺点：增加产品的相当麻烦，系统越来越复杂。

>>>>案例：

在前面汽车案例的基础上，再增加一个轮船产品，最后通过一个Factory方法，根据传入参数的不同，获取不同的对象

1、Ship

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public interface Ship {
}

2、CruiseShip

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class CruiseShip implements Ship{
}

3、FreighterShip

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class FreighterShip implements Ship{
}

4、Factory

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public interface Factory {
    Ship getInstance(ShipEnum shipEnum);
    Car  getInstance(CarEnum carEnum);
}

5、ShipEnum

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public enum ShipEnum {
    freighter("Freighter"),
    cruise("Cruise");
    String carType;

    ShipEnum(String carType) {
        this.carType = carType;
    }
}

6、CarFactory

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class CarFactory implements Factory {

    @Override
    public Ship getInstance(ShipEnum shipEnum) {
        return null;
    }

    @Override
    public Car getInstance(CarEnum carType) {
        Car car = null;
        if(carType == null){
            return car;
        }
        switch (carType){
            case bmw:
                car = new BmwCar();
                break;
            case jaguar:
                car = new JaguarCar();
                break;
            case mercedes:
                car = new MercedesCar();
                break;
            default:
                return null;
        }
        return car;
    }
}

7、ShipFactory

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class ShipFactory implements Factory {
    @Override
    public Ship getInstance(ShipEnum shipType) {
        Ship ship = null;
        if(shipType == null){
            return ship;
        }
        switch (shipType){
            case cruise:
                ship = new CruiseShip();
                break;
            case freighter:
                ship = new FreighterShip();
                break;
            default:
                return null;
        }
        return ship;
    }

    @Override
    public Car getInstance(CarEnum carEnum) {
        return null;
    }
}

8、SuperFactory

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class SuperFactory {
    public Factory getInstance(SuperEnum superEnum){
        switch (superEnum){
            case ship:
                return new ShipFactory();
            case car:
                return new CarFactory();
            default:
                return null;
        }
    }
}

9、SuperEnum

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public enum SuperEnum {
    ship,
    car;
}

10、FactoryMain

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class FactoryMain {
    public static void main(String[] args) {
        SuperFactory superFactory = new SuperFactory();
        Factory factory = superFactory.getInstance(SuperEnum.car);
        Car car = factory.getInstance(CarEnum.jaguar);
        System.out.println("您的车>>>"+car.getClass().getName());

        Factory factory1 = superFactory.getInstance(SuperEnum.ship);
        Ship ship = factory1.getInstance(ShipEnum.cruise);
        System.out.println("您的船>>>"+ship.getClass().getName());
    }
}

11、执行结果

您的车>>>factory.JaguarCar
您的川>>>factory.CruiseShip

菜鸟教程：http://www.runoob/design-pattern/abstract-factory-pattern.html

一、工厂模式

日志记录器：记录可能记录到本地硬盘、系统事件、远程服务器等，用户可以选择记录日志到什么地方。
数据库访问，当用户不知道最后系统采用哪一类数据库，以及数据库可能有变化时。
设计一个连接服务器的框架，需要三个协议，"POP3"、"IMAP"、"HTTP"，可以把这三个作为产品类，共同实现一个接口。

1、Car

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public interface Car {
}

2、BmwCar

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class BmwCar implements Car{
}

3、JaguarCar

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class JaguarCar implements Car {
}

4、MercedesCar

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class MercedesCar  implements Car{
}

5、CarEnum

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public enum CarEnum {
    bmw("BMW"),
    jaguar("Jaguar"),
    mercedes("Mercedes");
    String carType;
    String desc;

    CarEnum(String carType) {
        this.carType = carType;
    }

}

6、CarFactoryMain

package factory;

import static factory.CarEnum.jaguar;

/**
 * Created by yanshao on 2019/1/4.
 */
public class CarFactoryMain {

    public static void main(String[] args) {
        Car car = getInstance(jaguar);
        System.out.println("您的汽车>>>"+car.getClass().getName());
    }
    public static Car getInstance(CarEnum carType){
        Car car = null;
        if(carType == null){
            return car;
        }
        switch (carType){
            case bmw:
                car = new BmwCar();
                break;
            case jaguar:
                car = new JaguarCar();
                break;
            case mercedes:
                car = new MercedesCar();
                break;
            default:
                return null;
        }
        return car;
    }

}

7、执行结果

您的汽车>>>factory.JaguarCar

二、抽象工厂模式

1、概念：

2、优点：当一个产品族中的多个对象被设计成一起工作时，它能保证客户端始终只使用同一个产品族中的对象。

3：缺点：增加产品的相当麻烦，系统越来越复杂。

>>>>案例：

在前面汽车案例的基础上，再增加一个轮船产品，最后通过一个Factory方法，根据传入参数的不同，获取不同的对象

1、Ship

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public interface Ship {
}

2、CruiseShip

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class CruiseShip implements Ship{
}

3、FreighterShip

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class FreighterShip implements Ship{
}

4、Factory

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public interface Factory {
    Ship getInstance(ShipEnum shipEnum);
    Car  getInstance(CarEnum carEnum);
}

5、ShipEnum

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public enum ShipEnum {
    freighter("Freighter"),
    cruise("Cruise");
    String carType;

    ShipEnum(String carType) {
        this.carType = carType;
    }
}

6、CarFactory

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class CarFactory implements Factory {

    @Override
    public Ship getInstance(ShipEnum shipEnum) {
        return null;
    }

    @Override
    public Car getInstance(CarEnum carType) {
        Car car = null;
        if(carType == null){
            return car;
        }
        switch (carType){
            case bmw:
                car = new BmwCar();
                break;
            case jaguar:
                car = new JaguarCar();
                break;
            case mercedes:
                car = new MercedesCar();
                break;
            default:
                return null;
        }
        return car;
    }
}

7、ShipFactory

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class ShipFactory implements Factory {
    @Override
    public Ship getInstance(ShipEnum shipType) {
        Ship ship = null;
        if(shipType == null){
            return ship;
        }
        switch (shipType){
            case cruise:
                ship = new CruiseShip();
                break;
            case freighter:
                ship = new FreighterShip();
                break;
            default:
                return null;
        }
        return ship;
    }

    @Override
    public Car getInstance(CarEnum carEnum) {
        return null;
    }
}

8、SuperFactory

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class SuperFactory {
    public Factory getInstance(SuperEnum superEnum){
        switch (superEnum){
            case ship:
                return new ShipFactory();
            case car:
                return new CarFactory();
            default:
                return null;
        }
    }
}

9、SuperEnum

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public enum SuperEnum {
    ship,
    car;
}

10、FactoryMain

package factory;

/**
 * Created by yanshao on 2019/1/4.
 */
public class FactoryMain {
    public static void main(String[] args) {
        SuperFactory superFactory = new SuperFactory();
        Factory factory = superFactory.getInstance(SuperEnum.car);
        Car car = factory.getInstance(CarEnum.jaguar);
        System.out.println("您的车>>>"+car.getClass().getName());

        Factory factory1 = superFactory.getInstance(SuperEnum.ship);
        Ship ship = factory1.getInstance(ShipEnum.cruise);
        System.out.println("您的船>>>"+ship.getClass().getName());
    }
}

11、执行结果

您的车>>>factory.JaguarCar
您的川>>>factory.CruiseShip

USB迷 | 专注于互联网分享

设计模式-工厂模式、抽象工厂模式

菜鸟教程：http://www.runoob/design-pattern/abstract-factory-pattern.html

一、工厂模式

二、抽象工厂模式

菜鸟教程：http://www.runoob/design-pattern/abstract-factory-pattern.html

一、工厂模式

二、抽象工厂模式

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