Java中通过通用接口实现多态方法调用：处理共享同名方法的设计模式

public class FruitProcessor {
    public String showObjSpec(Object fruit) {
        // 编译错误：Object类没有showSpecifications()方法
        // fruit.showSpecifications();
        return "Error: Cannot call showSpecifications() on Object type.";
    }
}

/**
 * 定义一个通用的水果接口，包含展示规格的方法
 */
public interface Fruit {
    String showSpecifications();
}

/**
 * 苹果类实现Fruit接口
 */
public class Apple implements Fruit {
    @Override
    public String showSpecifications() {
        return "Apple: A crisp, sweet fruit, typically red or green.";
    }
}

/**
 * 橙子类实现Fruit接口
 */
public class Orange implements Fruit {
    @Override
    public String showSpecifications() {
        return "Orange: A citrus fruit, typically round, orange-colored, and sweet.";
    }
}

/**
 * 猕猴桃类实现Fruit接口
 */
public class Kiwi implements Fruit {
    @Override
    public String showSpecifications() {
        return "Kiwi: A small, oval fruit with a fuzzy brown skin and bright green flesh.";
    }
}

// 如果Apple本身也是一个接口
public interface AdvancedApple extends Fruit {
    // 可以提供默认实现
    default String showSpecifications() {
        return "Advanced Apple: Enhanced crispness and flavor.";
    }
    // 也可以定义其他特有方法
    void processApple();
}

/**
 * 水果处理器，能够统一处理实现了Fruit接口的对象
 */
public class FruitProcessor {
    /**
     * 展示任何实现了Fruit接口的对象的规格
     *
     * @param fruit 实现了Fruit接口的水果对象
     * @return 该水果的规格描述
     */
    public String showObjSpec(Fruit fruit) {
        // 编译通过，因为Fruit接口定义了showSpecifications()方法
        return fruit.showSpecifications();
    }
}

public class Main {
    public static void main(String[] args) {
        // 创建不同类型的水果对象
        Apple apple = new Apple();
        Orange orange = new Orange();
        Kiwi kiwi = new Kiwi();

        // 创建水果处理器
        FruitProcessor processor = new FruitProcessor();

        // 使用统一的方法处理不同类型的水果
        System.out.println(processor.showObjSpec(apple));
        System.out.println(processor.showObjSpec(orange));
        System.out.println(processor.showObjSpec(kiwi));

        // 也可以直接将接口引用指向具体实现
        Fruit myFruit = new Apple();
        System.out.println(processor.showObjSpec(myFruit));

        myFruit = new Orange();
        System.out.println(processor.showObjSpec(myFruit));
    }
}

Apple: A crisp, sweet fruit, typically red or green.
Orange: A citrus fruit, typically round, orange-colored, and sweet.
Kiwi: A small, oval fruit with a fuzzy brown skin and bright green flesh.
Apple: A crisp, sweet fruit, typically red or green.
Orange: A citrus fruit, typically round, orange-colored, and sweet.