工厂方法

Factory.java

public class Factory {

    public static void main(String[] args) {
        Dog dog = new FactoryDog().create();
        dog.walk();

        Cat cat = new FactoryCat().create();
        cat.walk();
    }

    public interface Animal {
        void walk();
    }

    public static class Dog implements Animal {

        @Override
        public void walk() {
            System.out.println(">>> dog");
        }
    }

    public static class Cat implements Animal {

        @Override
        public void walk() {
            System.out.println(">>> cat");
        }
    }

    public interface FactoryAnimal {
        Animal create();
    }

    public static class FactoryDog implements FactoryAnimal {

        @Override
        public Dog create() {
            return new Dog();
        }
    }

    public static class FactoryCat implements FactoryAnimal {

        @Override
        public Cat create() {
            return new Cat();
        }
    }

}