我只想快速查看一下我是否正确地执行了不同的飞行策略。
这个程序只是由一个duck类组成，该类使用一个接口作为它的fly方法。接口有不同的实现（即simplefly和nofly），switch语句根据specie enum选择正确的方法。
据我所知，strategy模式旨在避免在同一级别的子类之间出现重复代码，从而降低可维护性和可扩展性。因此，我们将相关的算法抽象到接口中，并根据需要进行选择。
代码：

package DesignPatterns;

//Here we will separate the fly method of ducks into implementations of an internface and then instantiate ducks with those attributes

interface IFly {

    public void fly();

}

//These are called strategies
class SimpleFly implements IFly {

    @Override
    public void fly() {
        System.out.println("Quack Quack i am flying in the air");
    }

}

class NoFly implements IFly {

    @Override
    public void fly() {
        System.out.println("I cannot fly.");
    }

}

//Now the base class just has to implement one of these strategies
class Duck {

    private IFly flyType;

    public enum SPECIE {
        WILD, CITY, RUBBER
    }

    public Duck(SPECIE specie) {
        switch(specie) {

            //Here just select the algorithms you want to assign to each type of DUCK. More flexible than horizontal code between species.
            case WILD:
            case CITY:
                this.flyType = new SimpleFly();
                break;
            case RUBBER:
                this.flyType = new NoFly();
                break;
            default:
                //If a new enum is defined but no definition yet, this stops code from breaking
                this.flyType = new SimpleFly();
        }
    }

    public void fly() {
        flyType.fly();
    }

}

输出正确，如本例所示：

Duck rubberDuck = new Duck(Duck.SPECIE.RUBBER);
        Duck normalDuck = new Duck(Duck.SPECIE.WILD);

        rubberDuck.fly();
        normalDuck.fly();

产量：

I cannot fly.
Quack Quack i am flying in the air

提前谢谢你，请让我知道我知识上的任何差距，sshawarma