java继承8个题

1、实现如下类之间的继承关系，并编写Music类来测试这些类。

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

public class Wind extends Instrument{
    //复写play方法
    public void play(){
        System.out.println("弹奏Wind!");
    }
    public void play2(){
        System.out.println("调用wind的play2");
    }
}

public class Brass extends Instrument {
    //复写play方法
    public void play(){
        System.out.println("弹奏brass!");
    }
    public void play2(){
        System.out.println("调用brass的play2！");
    }
}

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();
        tune(w);
        tune(b);
    }
}

2、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）。

public class People {
    protected double height;
    protected double weight;
    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 void speakHello(){
        System.out.println("你好！！！");
    }
    public void averageHeight(){
        System.out.println("平均身高是："+height);
    }
    public void averageWeight(){
        System.out.println("平均体重是："+weight);
    }
}

public class ChinaPeople extends People {
    public void speakHello(){
        System.out.println("你好，我是中国人！");
    }
    public void averageHeight(){
        System.out.println("中国人的平均身高是："+height);
    }
    public void averageWeight(){
        System.out.println("中国人的平均体重是："+weight);
    }
    public void chinaGongfu(){
        System.out.println("我会中国功夫：坐如钟，站如松，睡如弓！");
    }
}

public class AmericanPeople extends People {
    public void speakHello(){
        System.out.println("你好，我是美国人！");
    }
    public void averageHeight(){
        System.out.println("美国人的平均身高是："+height);
    }
    public void averageWeight(){
        System.out.println("美国人的平均体重是："+weight);
    }
    public void amercianBoxing(){
        System.out.println("我会美式拳击：直拳，上勾拳！");
    }
}

public class TestPeople {
    public static void main(String[] args) {
        ChinaPeople chp=new ChinaPeople();
        chp.height=180;
        chp.weight=130;
        chp.speakHello();
        chp.averageHeight();
        chp.averageWeight();
        chp.chinaGongfu();
        AmericanPeople amp=new AmericanPeople();
        amp.setHeight(175);
        amp.setWeight(150);
        amp.speakHello();
        amp.averageHeight();
        amp.averageWeight();
        amp.amercianBoxing();
    }
}

3、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。

(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。

(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。

public class Monkey {
    private String name;           //声明属性name
    //getter、setter方法
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    //构造方法
    Monkey(String s){
        this.name=s;
    }
    //成员方法
    public void speak(){
        System.out.println("咿咿呀呀.........");
    }
}

public class People00 extends Monkey {
    People00(String s) {
        super(s);
    }
    //重写speak()方法
    public void speak(){
        System.out.println("小样的，不错嘛！会说话了！");
    }
    void think(){
        System.out.println("别说话！认真思考！");
    }
}

public class E {
    public static void main(String[] args) {
        Monkey m=new Monkey("Toney");
        System.out.println("我是猴子"+m.getName());
        m.speak();
        People00 p=new People00("Tom");
        System.out.println("我是人类"+p.getName());
        p.speak();
        p.think();
    }
}

4、定义类Human，具有若干属性和功能；定义其子类Man、Woman；在主类Test中分别创建子类、父类和上转型对象，并测试其特性。

public class Human {
    private String name;
    private int age;
    private String sex;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public void speak(){
        System.out.println("I am a human.");
    }
    public void run(){
        System.out.println("I can run.");
    }
    public void getInfo(){
        System.out.println("我的名字是："+getName()+" 我的年龄是："+getAge()+" 我的性别是："+getSex());
        Man m=new Man();
    }
}

public class Man extends Human{
    public void man(){
        if(getSex()=="男人"){
            System.out.println("I am a man.");
        }
        else{
            System.out.println("I am not a man.");
        }
    }
    public void run(){
        System.out.println("我是雄狮一样强壮的男人.");
    }
}

public class Woman extends Human {
    public void woman(){
        if(getSex()=="女"){
            System.out.println("I am a woman.");
        }
        else{
            System.out.println("I am not a woman.");
        }
    }
}

public class TestHuman {
    public static void main(String[] agrs){
        Man m=new Man();
        m.setName("Dave");
        m.setAge(28);
        m.setSex("男");
        m.getInfo();
        m.speak();
        m.run();
        m.man();
        //隐式转换
        //上转型对象
        Human h=new Woman();
        h.setName("Jude");
        h.setAge(58);
        h.setSex("女");
        h.speak();
        h.run();
        h.getInfo();
        if(h instanceof Woman){
            Woman w=(Woman)h;
            w.woman();
        }
        else{
            System.out.println("类型不符！");
        }
    }
}

5、编写一个Animal类，具有属性：种类；具有功能：吃、睡。定义其子类Fish和Dog，定义主类E，在其main方法中分别创建其对象并测试对象的特性。

public class Animal {
    private String zhonglei;
    private String name;
    public String getZhonglei() {
        return zhonglei;
    }
    public void setZhonglei(String zhonglei) {
        this.zhonglei = zhonglei;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public void eat(){
        System.out.println("我需要觅食！");
    }
    public void sleep(){
        System.out.println("我需要睡觉！");
    }
    public void getInfo(){
        System.out.println("我的名字是："+getName()+" 我的种类是："+getZhonglei());
    }
}

public class Fish extends Animal {
    public void speak(){
        System.out.println("我是"+getZhonglei());
    }
    public void eat(){
        System.out.println("我吃鱼食！");
    }
}

public class Dog extends Animal{
    public void speak(){
        System.out.println("我是"+getZhonglei());
    }
    public void eat(){
        System.out.println("我吃狗粮！");
    }
}

public class TestAnimal {
    public static void main(String[] args){
        Animal a=new Fish();
        a.setName("Tom");
        a.setZhonglei("动物");
        a.getInfo();
        a.eat();
        a.sleep();
        if(a instanceof Fish){
            Fish f=(Fish)a;
            f.setZhonglei("鱼类");
            f.eat();
            f.getInfo();
        }
        else{
            System.out.println("类型不符！");
        }
        Dog d = new Dog();
        d.setName("哮天犬");
        d.setZhonglei("哺乳动物");
        d.getInfo();
        Animal aa=(Dog)d;
        aa.eat();
        aa.sleep();
    }
}

6、按要求编写一个Java应用程序：

（1）定义一个类，描述一个矩形，包含有长、宽两种属性，和计算面积方法。

（2）编写一个类，继承自矩形类，同时该类描述长方体，具有长、宽、高属性，和计算体积的方法。

（3）编写一个测试类，对以上两个类进行测试，创建一个长方体，定义其长、宽、高，输出其底面积和体积。

public class Juxing {
    private double chang;
    private double kuan;
    public double getChang() {
        return chang;
    }
    public void setChang(double chang) {
        this.chang = chang;
    }
    public double getKuan() {
        return kuan;
    }
    public void setKuan(double kuan) {
        this.kuan = kuan;
    }
    public double area(){
        return chang*kuan;
    }
}

public class ChangFangTi extends Juxing {
    private double gao;
    public double getGao() {
        return gao;
    }
    public void setGao(double gao) {
        this.gao = gao;
    }
    public double tiji(){
        return area()*gao;
    }
}

public class Test {
    public static void main(String[] args){
        ChangFangTi a=new ChangFangTi();
        a.setChang(12);
        a.setKuan(10);
        a.setGao(5);
        System.out.println("长方体的底面积是："+a.area());
        System.out.println("长方体的体积是："+a.tiji());
    }
}

7、编写一个Java应用程序，设计一个汽车类Vehicle，包含的属性有车轮个数wheels和车重weight。小车类Car是Vehicle的子类，其中包含的属性有载人数loader。卡车类Truck是Car类的子类，其中包含的属性有载重量payload。每个类都有构造方法和输出相关数据的方法。最后，写一个测试类来测试这些类的功能。

public class Vehicle {
    private int wheels;
    private double weight;
    public int getWheels() {
        return wheels;
    }
    public void setWheels(int wheels) {
        this.wheels = wheels;
    }
    public double getWeight() {
        return weight;
    }
    public void setWeight(double weight) {
        this.weight = weight;
    }
    Vehicle(){

    }
    Vehicle(int wheels,double weight){
        this.wheels=wheels;
        this.weight=weight;
    }
    public void getInfo(){
        System.out.println("车轮的个数是："+wheels+" 车重："+weight);
    }
}

public class Car extends Vehicle {
    private int loader;
    public int getLoader() {
        return loader;
    }
    public void setLoader(int loader) {
        this.loader = loader;
    }
    Car(){

    }
    Car(int wheels,double weight,int loader){
        super(wheels,weight);
        this.loader=loader;
    }
    public void loader(){
        if(loader<=6){
            System.out.println("这辆车能载"+loader+"人");
        }
        else{
            System.out.println("超员了");
        }
    }
}

public class Truck extends Car {
    Truck(){
        super();
    }
    private double payload;
    public double getPayload() {
        return payload;
    }
    public void setPayload(double payload) {
        this.payload = payload;
    }
    public void payload(){
        if(payload<=1000){
            System.out.println("这辆车的载重是"+payload);
        }
        else{
            System.out.println("超重了");
        }
    }
}

public class Testcar {
    public static void main(String[] args){
        Car c=new Car(4,600,4);
        c.getInfo();
        c.loader();
        Truck t =new Truck();
        t.setLoader(3);
        t.setPayload(800);
        t.setWeight(1000);
        t.setWheels(6);
        t.getInfo();
        t.loader();
        t.payload();
    }
}

8、编写一个Shape类，具有属性：周长和面积；定义其子类三角形和矩形，分别具有求周长的方法。定义主类E，在其main方法中创建三角形和矩形类的对象，并赋给Shape类的对象a、b，使用对象a、b来测试其特性。

public class Shape {
    private int bian;
    private double zhouchang;
    private double mianji;
    public int getBian() {
        return bian;
    }
    public void setBian(int bian) {
        this.bian = bian;
    }
    public double getZhouchang() {
        return zhouchang;
    }
    public void setZhouchang(double zhouchang) {
        this.zhouchang = zhouchang;
    }
    public double getMianji() {
        return mianji;
    }
    public void setMianji(double mianji) {
        this.mianji = mianji;
    }
    public void bian(){
        System.out.println("您创建了一个"+bian+"边形！");
    }
}

public class San extends Shape{
    double[] bianchang=new double[3];
    San(){

    }
    San(double a,double b, double c){
        bianchang[0]=a;
        bianchang[1]=b;
        bianchang[2]=c;
    }
    public void zhouchang(){
        if(getBian()==3&&bianchang[0]+bianchang[1]>bianchang[2]&&bianchang[0]-bianchang[1]<bianchang[2]){
            double sum=0;
            for(int i=0;i<bianchang.length;i++){
                sum+=bianchang[i];
                System.out.print(" 边长"+(i+1)+"是"+ bianchang[i]);
            }
            System.out.println(" 三角形的周长是："+sum);
        }
        else{
            System.out.println("这不是一个三角形");
        }
    }
}

public class Juxx extends Shape {
    double[] bianchang=new double[4];
    Juxx(){}
    Juxx(double a,double b,double c,double d){
        bianchang[0]=a;
        bianchang[1]=b;
        bianchang[2]=c;
        bianchang[3]=d;
    }
    public void zhouchang(){
        if(getBian()==4 && bianchang[0]==bianchang[2]&&bianchang[1]==bianchang[3]){
            double sum=0;
            for(int i=0;i<bianchang.length;i++){
                sum+=bianchang[i];
                System.out.print(" 边长"+(i+1)+"是"+bianchang[i]);
            }
            System.out.println(" 矩形的周长是："+sum);
        }
        else{
            System.out.println("这不是一个矩形");
        }
    }
}

public class TestE {
    public static void main(String[] args){
        Shape s=new Shape();
        s.setBian(5);
        s.bian();
        San sa=new San(3,4,5);
        sa.setBian(3);
        sa.zhouchang();
        Juxx ju=new Juxx(3,4,3,4);
        ju.setBian(4);
        ju.zhouchang();
    }
}