工厂模式 Factory Pattern

// 汽车产品接口类
public interface Car {
    public void drive();
}
// 不同的汽车产品类
public class Audi implements Car {
    @Override
    public void drive() {
        System.out.println("Driving AUDI Sedans");
    }
}
public class Benz implements Car {
    @Override
    public void drive() {
        System.out.println("Driving BENZ Sedans");
    }
}
public class Bwm implements Car {
    @Override
    public void drive() {
        System.out.println("Driving BWM Sedans");
    }
}
// 简单工厂类
public class SimpleFactory {
    public static Car drive(String carType) {
        if (StringUtils.isBlank(carType)) {
            throw new RuntimeException("carType can not be empty.");
        }
        Car car = null;
        switch (carType.toLowerCase()) {
            case "bwm":
                car = new Bwm();
                break;
            case "benz":
                car = new Benz();
                break;
            case "audi":
                car = new Audi();
                break;
            default:
                throw new RuntimeException("invalid data.");
        }
        return car;
    }
}
// 测试类
public class SimpleFactoryTest {
    @org.junit.Test
    public void drive() {
        Car car = SimpleFactory.drive("Bwm");
        if (car != null) {
            car.drive();
        }
        car = SimpleFactory.drive("BENZ");
        if (car != null) {
            car.drive();
        }
        car = SimpleFactory.drive("audi");
        if (car != null) {
            car.drive();
        }
    }
}

// 创建抽象工厂类
public abstract class CarFactory {
    abstract public Car drive();
}
// 三个产品的实现类
public class AudiFactory extends CarFactory {
    @Override
    public Car drive() {
        return new Audi();
    }
}
public class BenzFactory extends CarFactory {
    @Override
    public Car drive() {
        return new Benz();
    }
}
public class BwmFactory extends CarFactory {
    @Override
    public Car drive() {
        return new Bwm();
    }
}
// 测试类
public class CarFactoryTest {
    @org.junit.Test
    public void drive() {
        CarFactory factory = new BwmFactory();
        Car car = factory.drive();
        if (car != null) {
            car.drive();
        }
        factory = new BenzFactory();
        car = factory.drive();
        if (car != null) {
            car.drive();
        }
        factory = new AudiFactory();
        car = factory.drive();
        if (car != null) {
            car.drive();
        }
    }
}