VIP31/spring-demo/src/main/java/com/sf/Main.java

package com.sf;

public class Main {

    // 三个重载方法，参数类型分别为以上三种类型
    static void sayHello(Human human) {
        System.out.println("human say Hello");
    }

    static void sayHello(Man man) {
        System.out.println("man say Hello");
    }

    static void sayHello(Woman woman) {
        System.out.println("woman say Hello");
    }

    public static void main(String[] args) {
        Human man = new Man();
        Human woman = new Woman();
        sayHello(man);
        sayHello(woman);
    }
}

// 声明一个父类 两个子类
class Human {
}

class Man extends Human {
}

class Woman extends Human {
}