设计模式之简单工厂模式

Posted 2021-01-02 lzh110

简单画图理解

//设计模式之简单工厂模式
//创建一个食物类
interface Food {
    void eat();
}

//我今天想吃薯条或汉堡
class Hamburger implements Food {

    @Override
    public void eat() {
        System.out.println("我吃汉堡");
    }
}

class FrenchFries implements Food {

    @Override
    public void eat() {
        System.out.println("我吃薯条");
    }
}

//我到速食店了，要开始点餐了
class FoodFactory {
    static Food createFood(String name) {
        Food food = null;
        switch (name) {
            case "汉堡":
                food = new Hamburger();
                break;
            case "薯条":
                food = new FrenchFries();
                break;
        }
        return food;
    }
}

public class Demo3 {
    public static void main(String[] args) {
        //我全部都要
        Food hamburger = FoodFactory.createFood("汉堡");
        hamburger.eat();
        Food frenchFries = FoodFactory.createFood("薯条");
        frenchFries.eat();
    }
}

输出：
我吃汉堡
我吃薯条

 

但是这段代码需要改进，因为汉堡有很多种类，薯条也有不同的类型

 

//创建一个食物类
interface Food {
    void eat();
}

//我今天想吃薯条或汉堡
class Hamburger implements Food {

    @Override
    public void eat() {
        System.out.println("我要吃奥尔良烤鸡腿堡");
    }
}

class FrenchFries implements Food {

    @Override
    public void eat() {
        System.out.println("我要吃皱纹炸薯条");
    }
}

class HamburgerFactory {
     static Hamburger createHamburger() {
        return new Hamburger();
    }
}

class FrenchFriesFactory {
     static FrenchFries createFrenchFries() {
        return new FrenchFries();
    }
}

//我到速食店了，要开始点餐了
//class FoodFactory {
//    static Food createFood(String name) {
//        Food food = null;
//        switch (name) {
//            case "汉堡":
//                food = new Hamburger();
//                break;
//            case "薯条":
//                food = new FrenchFries();
//                break;
//        }
//        return food;
//    }
//}

public class Demo3 {
    public static void main(String[] args) {
        //我全部都要
//        Food hamburger = FoodFactory.createFood("汉堡");
//        hamburger.eat();
//        Food frenchFries = FoodFactory.createFood("薯条");
//        frenchFries.eat();
        Hamburger hamburger = HamburgerFactory.createHamburger();
        hamburger.eat();
        FrenchFries frenchFries = FrenchFriesFactory.createFrenchFries();
        frenchFries.eat();
    }
}

输出：
我要吃奥尔良烤鸡腿堡
我要吃皱纹炸薯条