工厂模式（二）工厂方法模式

简单工厂的弊端可以用工厂方法一定程度的避免；

public interface Screw {
	
	public void useScrew();
}

public class EgihtScrew implements Screw{

	@Override
	public void useScrew() {
		System.out.println("使用8号螺丝。");
	}
}

public class SixScrew implements Screw{

	@Override
	public void useScrew() {
		System.out.println("使用6号螺丝。");;
	}
}

public class SevenScrew implements Screw {

	@Override
	public void useScrew() {
		System.out.println("使用7号螺丝。");
	}
}

public interface ScrewFactory {

	public Screw produceScrew();
}

public class EgihtScrewFactory implements ScrewFactory{

	@Override
	public Screw produceScrew() {
		return new EgihtScrew();
	}
}

public class SixScrewFactory implements ScrewFactory{

	@Override
	public Screw produceScrew() {
		return new SixScrew();
	}
}

public class SevenScrewFactory implements ScrewFactory{

	@Override
	public Screw produceScrew() {
		return new SevenScrew();
	}
}

public class Store {

	public static void main(String[] args) {
		ScrewFactory factory = new SevenScrewFactory();
		Screw screw = factory.produceScrew();
		screw.useScrew();
	}
}

优点：

• 当需要新增产品的时候，只需要新建一个产品类和对应的工厂类即可；