Java设计模式-工厂模式

简单工厂模式

简单工厂的定义：提供一个创建对象实例的功能，而无须关心其具体实现。被创建实例的类型可以是接口、抽象类，也可以是具体的类
实现汽车接口

public interface Car {
    String getName();
}

奔驰类

public class Benz implements Car {
    @Override
    public String getName() {
        return "Benz";
    }
}

宝马类

public class BMW implements Car {
    @Override
    public String getName() {
        return "BMW";
    }
}

简单工厂，既能生产宝马又能生产奔驰

public class simpleFactory {
    public Car getCar(String name) {
        if ( name.equals("BMW")) {
            return new BMW();
        }  else if ( name.equals("Benz")) {
            return new Benz();
        } else {
            System.out.println("no");
            return null;
        }
    }
}

测试类

public class SimpleFactoryTest {
    public static void main(String[] args) {
        simpleFactory simple = new simpleFactory();
        Car car = simple.getCar("BMW");
        System.out.println(car.getName());
    }
}

工厂方法

工厂接口

public interface Factory {
    Car getCar();
}

奔驰工厂

public class BenzFactory implements Factory {
    @Override
    public Car getCar() {
        return new Benz();
    }
}

宝马工厂

public class BMWFactory implements Factory {
    @Override
    public Car getCar() {
        return new BMW();
    }
}

测试类

public static void main(String[] args) {
    Factory bmwFactory = new BMWFactory();
    System.out.println(bmwFactory.getCar().getName());
    Factory benzFactory = new BenzFactory();
    System.out.println(benzFactory.getCar().getName());
}

抽象工厂

抽象工厂

public abstract class AbastractFactory {
    protected abstract Car getCar();
    public Car getCar(String name) {
        if ( "BMW".equalsIgnoreCase(name)) {
            return new BMWFactory().getCar();
        } else if ( "Benz".equalsIgnoreCase(name) ) {
            return new BenzFactory().getCar();
        } else {
            return null;
        }
    }
}