工厂模式

public interface Animal {
    void eat();
}

public class Dog implements Animal {
    @Override
    public void eat() {
        System.out.println("dog eat......");
    }
}

public class AnimalFactory {
    public static Animal getAnimal(String type) throws ClassNotFoundException, IllegalAccessException, InstantiationException {
       // test.demo03.factorymode.Dog
        Class<?> aClass = Class.forName(AnimalFactory.class.getPackage().getName() + "." + type);
        Object o = aClass.newInstance();
        return (Animal) o;
    }
}

// 利用工厂来获取指定的类

public class Main {
    public static void main(String[] args) throws IllegalAccessException, InstantiationException, ClassNotFoundException {
        Animal dog = AnimalFactory.getAnimal("Dog");
        dog.eat();
    }
}