工厂模式

工厂模式（实现了创建者与调用者的分离）

核心本质：实例化对象，用工厂方法代替new操作；将选择实现类、创建对象统一管理和控制，从而将调用者跟我们的实现类解耦。

分类

1 简单工厂模式:用来生产同一等级结构中的任意产品，只有一个工厂类。也叫静态工厂模式，就是工厂类一般使用静态方法，通过接受的参数来返回不同的对象实例（缺点：对于增加新的产品，需要修改已有代码，违反了开闭原则）

 

2 工厂方法模式：有一组实现了相同接口的工厂类，不修改已有类的基础上，通过增加新的工厂类实现扩展

根据设计理论建议：工厂方法模式，但实际上一般使用简单工厂模式

 

3 抽象工厂模式：用来生产不同产品族的全部产品（不可以增加产品，但可以增加产品族）；是工厂方法模式的升级版，在有多个业务品种，业务分类时，通过抽象工厂模式产生需要的对象是一种非常好的解决方式。

Java代码：

1简单工厂模式：

package factory.simplefactory;public class Audi implements Car {@Overridepublic void run() {System.out.println("奥迪在跑！");}}

package factory.simplefactory;public class Byd implements Car {@Overridepublic void run() {System.out.println("比亚迪在跑！");}}

package factory.simplefactory;public interface Car {void run();}

package factory.simplefactory;public class CarFactory {public static Car createCar(String type) {if ("奥迪".equals(type)) {return new Audi();} else if ("比亚迪".equals(type)) {return new Byd();} else {return null;}}}

package factory.simplefactory;//简单工厂类public class CarFactory2 {public static Car createAudi() {return new Audi();}public static Car createByd() {return new Byd();}}

注：CarFactory与CarFactory2都可以用在简单工厂模式

package factory.simplefactory;//测试在没有工厂模式的情况下public class Client01 { // 调用者public static void main(String[] args) {Car c1 = new Audi();Car c2 = new Byd();c1.run();c2.run();}}

package factory.simplefactory;//测试在简单工厂模式的情况下public class Client02 { // 调用者public static void main(String[] args) {Car c1 = CarFactory.createCar("奥迪");Car c2 = CarFactory.createCar("比亚迪");c1.run();c2.run();}}

注：Client01是在没有简单工厂模式下的测试类，Client02是在有简单工厂模式下的测试类

2  工厂方法模式

package factory.factorymethod;public class Audi implements Car {@Overridepublic void run() {System.out.println("奥迪在跑！");}}

package factory.factorymethod;public class Byd implements Car {@Overridepublic void run() {System.out.println("比亚迪在跑！");}}

package factory.factorymethod;public interface Car {void run();}

package factory.factorymethod;public interface CarFactory {Car createCar();}

package factory.factorymethod;public class AudiFactory implements CarFactory {public Car createCar() {return new Audi();}}

package factory.factorymethod;public class BydFactory implements CarFactory {public Car createCar() {return new Audi();}}

package factory.factorymethod;public class Client {public static void main(String[] args) {Car c1 = new AudiFactory().createCar();Car c2 = new BydFactory().createCar();c1.run();c2.run();}}

3 抽象工厂模式：

package factory.abstractFactory;public interface Engine {void run();void start();}class LuxuryEngine implements Engine {public void run() {System.out.println("转的快！");}public void start() {System.out.println("启动快！可以自动启停！");}}class LowEngine implements Engine {public void run() {System.out.println("转的慢！");}public void start() {System.out.println("启动慢！");}}

package factory.abstractFactory;public interface Seat {void massage();// 按摩}class LuxurySeat implements Seat {public void massage() {System.out.println("可以自动按摩！");}}class LowSeat implements Seat {public void massage() {System.out.println("不可以自动按摩！");}}

package factory.abstractFactory;public interface Tyre {void revolve();}class LuxuryTyre implements Tyre {public void revolve() {System.out.println("旋转不磨损");}}class LowTyre implements Tyre {public void revolve() {System.out.println("旋转磨损快");}}

package factory.abstractFactory;public interface CarFactory {Engine createEngine();Seat createSeat();Tyre createTyre();}

package factory.abstractFactory;public class LuxuryCarFactory implements CarFactory {public Engine createEngine() {return new LuxuryEngine();}public Seat createSeat() {return new LuxurySeat();}public Tyre createTyre() {return new LuxuryTyre();}}

package factory.abstractFactory;public class LowCarFactory implements CarFactory {public Engine createEngine() {return new LowEngine();}public Seat createSeat() {return new LowSeat();}public Tyre createTyre() {return new LowTyre();}}

package factory.abstractFactory;public class Client {public static void main(String[] args) {CarFactory factory = new LuxuryCarFactory();Engine e = factory.createEngine();e.run();e.start();}}