用PHP代码实现简单的工厂模式

//家禽类
abstract class Fowl
{
	abstract public function eat();//吃方法
}

//牛类
class Cattle extends Fowl
{
	public function eat()
	{
		echo "我是牛，我吃草";
	}
}
//鸭类
class Duck extends Fowl
{
	public function eat()
	{
		echo "我是鸭，我吃鱼";
	}
}
//羊类
class Sheep extends Fowl
{
	public function eat()
	{
		echo "我是羊，我吃草";
	}
}

//工厂类
class Factory
{
	public static function create($fowlName)
	{
		switch ($fowlName) {
			case 'Cattle':
				return new Cattle();
				break;
			case 'Duck':
				return new Duck();
				break;
			case 'Sheep':
				return new Sheep();
				break;
		}
	}
}

$cattle = Factory::create('Cattle');
$cattle->eat();//我是牛，我吃草

$duck = Factory::create('Duck');
$duck->eat();//我是鸭，我吃鱼

$sheep = Factory::create('Sheep');
$sheep->eat();//我是羊，我吃草