java继承相关

Posted 2020-08-09

实现如下类之间的继承关系，并编写Music类来测试这些类。

 

package eryi;

public class Instrument {

    public void play()
    {
        System.out.println("弹奏乐器");
    }
}

wind：

package eryi;

public class Wind extends Instrument {

    public void play()
    {
        System.out.println("弹奏wind");
    }
    public void play2()
    {
        System.out.println("调用wind的play2");
    }
}

brass：

package eryi;

public class Brass extends Instrument {

    public void play()
    {
        System.out.println("弹奏brass");
    }
    public void play2()
    {
        System.out.println("调用brass的跑play2");
    }
}

package eryi;

public class MUSIC {
    public static void tune(Instrument i) {
        i.play();
    }

    public static void main(String args[]) {
        Wind w = new Wind();
        Brass b = new Brass();

        w.play();
        w.play2();
        b.play();
        b.play2();

    }

}

编写一个Java应用程序，该程序包括3个类：Monkey类、People类和主类

E。要求：

(1) Monkey类中有个构造方法：Monkey (String s)，并且有个public void speak()

方法，在speak方法中输出“咿咿呀呀......”的信息。

package eryi;

public class Monkey {

    Monkey(String s)
    {
        
    }
    public void speak()
    {
        System.out.println("咿咿呀呀...");
    }
}

(2)People类是Monkey类的子类，在People类中重写方法speak(),在speak方法

中输出“小样的，不错嘛！会说话了！”的信息。

(3)在People类中新增方法void think()，在think方法中输出“别说话！认真思考！”

的信息。

package eryi;

public class People1 extends Monkey {

    People1(String s) {
        super(s);
    
    }

    public void speak()
    {
        System.out.println("小样的，不错嘛！会说话了！");
    }
    
    public void think()
    {
        System.out.println("别说话！认真思考！");
    }
}

(4)在主类E的main方法中创建Monkey与People类的对象类测试这2个类的功

能。

package eryi;

public class E {

    public static void main(String[] args) {
        // TODO 自动生成的方法存根

        Monkey m=new Monkey("猴子");
        
        m.speak();
        
        People1 p=new People1("人类");
        
        p.speak();
        p.think();
    }

}

创建如下三个类：（People类中的三个方法分别输出一些信息，ChinaPeople

和AmericanPeople类重写父类的三个方法）。

 

People：

package eryi;

public class People {

    protected double height;
    protected double weight;
    private String person;
    
    public void speakHello()
    {
        System.out.println();
    }
    public void averageHeight()
    {
        System.out.println();
    }
    public void averageWight()
    {
        System.out.println();
    }
    public double getHeight() {
        return height;
    }
    public void setHeight(double height) {
        this.height = height;
    }
    public double getWeight() {
        return weight;
    }
    public void setWeight(double weight) {
        this.weight = weight;
    }
    public String getPerson() {
        return person;
    }
    public void setPerson(String person) {
        this.person = person;
    }
}

ChinaPeople：

package eryi;

public class ChinaPeople extends People{

    public void speakHello()
    {
        System.out.println("你好");
    }
    
    public void averageHeight()
    {
        System.out.println("平均身高：175cm");
    }
    
    public void averageWight()
    {
        System.out.println("平均体重：60kg");
    }
    
    public void chinaGongFu()
    {
        System.out.println("我可以坐如钟，站如松，睡如弓");
    }
}

AmericanPeople：

package eryi;

public class AmericanPeople extends People {

    public void speakHello()
    {
        System.out.println("Hello");
    }
    
    public void averageHeight()
    {
        System.out.println("平均身高：178cm");
    }
    
    public void averageWight()
    {
        System.out.println("平均体重：65kg");
    }
    
    public void americanBoxing()
    {
        System.out.println("我会直拳");
    }
}

测试：

package eryi;

public class Person {

    public static void main(String[] args) {
        // TODO 自动生成的方法存根

        ChinaPeople cp=new ChinaPeople();
        
        cp.setPerson("中国人");
        
        System.out.println(cp.getPerson());
        cp.speakHello();
        cp.averageHeight();
        cp.averageWight();
        cp.chinaGongFu();
        
        AmericanPeople ap=new AmericanPeople();
        
        ap.setPerson("美国人");
        
        System.out.println(ap.getPerson());
        ap.speakHello();
        ap.averageHeight();
        ap.averageWight();
        ap.americanBoxing();
        
    }

}