编写一个Java应用程序除了主类外该程序中还有4个类：People、ChinaPeople、AmericanPeople和BeijingPeople类。要求如下： People类有访问权限是protected的double型成员变量height和weight以及public void speakHello、public void averageHeight和public void averageW

People类代码：

public class People {
    protected double height;
    protected double weight;

    public void speakHello() {
        System.out.println("Hello!");
    }

    public void averageHeight() {
        System.out.println("The average height is 170cm.");
    }

    public void averageWeight() {
        System.out.println("The average weight is 65kg.");
    }
}

ChinaPeople类代码：

public class ChinaPeople extends People {
    public void chinaGongfu() {
        System.out.println("I can do China Gongfu.");
    }

    @Override
    public void speakHello() {
        System.out.println("你好！");
    }

    @Override
    public void averageHeight() {
        System.out.println("中国人的平均身高是170cm。");
    }

    @Override
    public void averageWeight() {
        System.out.println("中国人的平均体重是65kg。");
    }
}

AmericanPeople类代码：

public class AmericanPeople extends People {
    public void americanBoxing() {
        System.out.println("I can do American Boxing.");
    }

    @Override
    public void speakHello() {
        System.out.println("Hello!");
    }

    @Override
    public void averageHeight() {
        System.out.println("The average height of Americans is 175cm.");
    }

    @Override
    public void averageWeight() {
        System.out.println("The average weight of Americans is 75kg.");
    }
}

BeijingPeople类代码：

public class BeijingPeople extends ChinaPeople {
    public void beijingOpera() {
        System.out.println("I can do Beijing Opera.");
    }

    @Override
    public void speakHello() {
        System.out.println("您好！");
    }

    @Override
    public void averageHeight() {
        System.out.println("北京人的平均身高是173cm。");
    }

    @Override
    public void averageWeight() {
        System.out.println("北京人的平均体重是70kg。");
    }
}

Main方法代码：

public class Main {
    public static void main(String[] args) {
        People people = new People();
        people.speakHello();
        people.averageHeight();
        people.averageWeight();

        ChinaPeople chinaPeople = new ChinaPeople();
        chinaPeople.speakHello();
        chinaPeople.averageHeight();
        chinaPeople.averageWeight();
        chinaPeople.chinaGongfu();

        AmericanPeople americanPeople = new AmericanPeople();
        americanPeople.speakHello();
        americanPeople.averageHeight();
        americanPeople.averageWeight();
        americanPeople.americanBoxing();

        BeijingPeople beijingPeople = new BeijingPeople();
        beijingPeople.speakHello();
        beijingPeople.averageHeight();
        beijingPeople.averageWeight();
        beijingPeople.chinaGongfu();
        beijingPeople.beijingOpera();
    }
}
``