一、面向对象第一章上机作业参考答案（略）
可参考课堂Demo进行编写
二、面向对象第二章上机作业参考答案：
1、上机练习1——设计Dog和Penguin类 - 需求说明： – 运用面向对象思想抽象出Dog类和Penguin类，画出对应类图
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– 根据类图编写Dog类和Penguin类 – 添加默认构造方法
2、上机练习2——打印Dog信息2-1 - 需求说明： – 根据控制台提示信息选择领养宠物（狗）， ▪ 输入昵称、品种、健康值 ▪ 打印宠物信息 – 要保证健康值的有效性（在1到100之间） 3、上机练习3——Dog类的带参构造方法 - 需求说明： – 增加带参构造方法
Dog(String name, String strain)
– 修改Test类，使用带参构造方法创建对象 4、上机练习4——操作企鹅性别属性 - 需求说明： – 给Penguin类提供SEX_MALE和SEX_FEMALE两个静态常量，分别取值“Q仔”或“Q妹” – 修改Test类，使用静态常量对性别进行赋值 – 修改企鹅的性别只能取值“雄”或“雌”，通过修改静态变量实现该需求
参考：
Dog.java
package netclass05.homework2;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 15:42
* @Description: netclass05.homework2
* @version: 1.0
*/
public class Dog {
//昵称
private String name;
//健康值
private int health;
//亲密度
private int love;
//品种
private String strain;
public Dog(){
}
public Dog(String name, int health, String strain) {
this.name = name;
this.health = health;
this.strain = strain;
}
public Dog(String name, int health, int love, String strain) {
this.name = name;
this.health = health;
this.love = love;
this.strain = strain;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getHealth() {
return health;
}
public void setHealth(int health) {
if(health >= 1 &&health <= 100){
this.health = health;
}else{
System.out.println("你输入的健康值有误，请重新输入。");
}
}
public int getLove() {
return love;
}
public void setLove(int love) {
this.love = love;
}
public String getStrain() {
return strain;
}
public void setStrain(String strain) {
this.strain = strain;
}
// 输出信息
public void print(){
System.out.println("狗的昵称是：" +this.name + ",健康值：" +this.health + ",亲密度：" + this.love + ",品种是：" + this.strain);
}
}
Penguin.java
package netclass05.homework2;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 15:47
* @Description: netclass05.homework2
* @version: 1.0
*/
public class Penguin {
//昵称
private String name;
//健康值
private int health;
//亲密度
private int love;
//性别
private static String gender;
//添加静态常量
static final String SEX_MALE = "Q仔";
static final String SEX_FEMALE = "Q妹";
public Penguin() {
}
public Penguin(String name, int health, int love, String gender) {
this.name = name;
this.health = health;
this.love = love;
this.gender = gender;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getHealth() {
return health;
}
public void setHealth(int health) {
if(health >= 1 &&health <= 100){
this.health = health;
}else{
System.out.println("你输入的健康值有误，请重新输入。");
}
}
public int getLove() {
return love;
}
public void setLove(int love) {
this.love = love;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
if("雄".equals(gender)){
this.gender = "雄";
}else if("雌".equals(gender)){
this.gender = "雌";
}else{
System.out.println("您输入的性别有误，请重新输入！");
}
// this.gender = gender;
}
//输出方法
public void print(){
System.out.println("企鹅的昵称是：" +this.name + ",健康值：" +this.health + ",亲密度：" + this.love + ",性别是：" + this.gender);
}
public static void main(String[] args) {
// Penguin p = new Penguin("小黑",10,20,"雄性");
// Penguin p = new Penguin();
// p.setName("小白");
// p.setHealth(10);
// p.setLove(20);
// p.setGender("雄性");
// System.out.println(p.getName());
// p.print();
// 创建
}
}
TestDemo.java
package netclass05.homework2;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 16:32
* @Description: netclass05.homework2
* @version: 1.0
*/
public class TestDemo {
public static void main(String[] args) {
// //创建Scanner对象，接收键盘输入
// Scanner scanner = new Scanner(System.in);
// //读取昵称
// System.out.print("请输入狗的昵称：");
// String name = scanner.next();
// //读取品种
// System.out.print("请输入狗的品种：");
// String strain = scanner.next();
// //读取健康值
// System.out.print("请输入狗的健康值：");
// int health = scanner.nextInt();
//创建狗对象
// Dog dog = new Dog();
// dog.setName(name);
// dog.setStrain(strain);
// dog.setHealth(health);
// Dog dog = new Dog(name,health,strain);
// dog.print();
Penguin p = new Penguin();
p.setName("小白");
p.setHealth(30);
// p.setGender(Penguin.SEX_MALE);
p.setGender("雄性");
p.print();
}
}
三、面向对象第三章上机作业参考答案：
1、上机练习1已在第三章博客中编写，请参考；
链接地址：
【0基础学java】教学日志：javaSE-面向对象3-this关键字、static关键字、代码块、package、import、封装、访问修饰符
2、上机练习2
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参考：
父类Animal.java
package netclass05.homework3;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 15:21
* @Description: netclass05.homework3
* @version: 1.0
*/
public abstract class Animal {
//年龄
private int age;
public Animal(){
}
public Animal(int age){
this.age = age;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
//自我介绍的抽象方法
public abstract void introduce();
}
子类Fish.java
package netclass05.homework3;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 15:24
* @Description: netclass05.homework3
* @version: 1.0
*/
public class Fish extends Animal {
private int weight;
public Fish(){
}
public Fish(int age,int weight){
super(age);
this.weight = weight;
}
public int getWeight() {
return weight;
}
public void setWeight(int weight) {
this.weight = weight;
}
@Override
public void introduce() {
System.out.println("鱼的年龄是：" + super.getAge() + ",重量是：" + weight + "kg");
}
//子类特有的方法 游泳
public void swim(){
System.out.println("我是一条鱼，正在游泳呢... ...");
}
}
子类Bird.java
package netclass05.homework3;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 15:27
* @Description: netclass05.homework3
* @version: 1.0
*/
public class Bird extends Animal{
private String color;
public Bird(){
}
public Bird(int age,String color){
super(age);
this.color = color;
}
public void setColor(String color){
this.color = color;
}
public String getColor(){
return color;
}
@Override
public void introduce() {
System.out.println("鸟的年龄：" + super.getAge() +",颜色是：" +color);
}
//子类特有的方法 飞
public void fly(){
System.out.println("我是一只鸟，我正在飞... ...");
}
}
测试类AnimalTest.java
package netclass05.homework3;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 15:30
* @Description: netclass05.homework3
* @version: 1.0
*/
public class AnimalTest {
public static void main(String[] args) {
Fish fish = new Fish(17,2);
fish.introduce();
fish.swim();
Bird bird = new Bird(16,"彩色");
bird.introduce();
bird.fly();
}
}
四、面向对象第四章作业参考答案：
1、上机练习—使用多态实现主人领养宠物并与宠物玩耍
需求说明：
– 主人根据宠物编号领养宠物
– 主人和狗狗玩接飞盘游戏，狗狗健康值减少10，不主人亲密度增加5
– 主人和企鹅玩游泳游戏，企鹅健康值减少10，不主人亲密度增加5
2、上机练习——计算一次租赁多辆汽车的总租金
编辑
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添加图片注释，不超过 140 字（可选）
3、上机练习——购置新车
编辑
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添加图片注释，不超过 140 字（可选）
编辑
切换为居中
添加图片注释，不超过 140 字（可选）
参考：
机动车类 MotoVehical.java
package netclass04.abstracts.homework;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/12 - 01 - 12 - 16:23
* @Description: netclass04.abstracts.homework
* @version: 1.0
*/
public abstract class MotoVehical {
private String no;
private String brand;
public MotoVehical(){
}
public MotoVehical(String no, String brand) {
this.no = no;
this.brand = brand;
}
public String getNo() {
return no;
}
public void setNo(String no) {
this.no = no;
}
public String getBrand() {
return brand;
}
public void setBrand(String brand) {
this.brand = brand;
}
//抽象方法（根据天数计算租金）
public abstract int calcRent(int days);
}
轿车类 Car.java
package netclass04.abstracts.homework;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/12 - 01 - 12 - 16:25
* @Description: netclass04.abstracts.homework
* @version: 1.0
*/
public class Car extends MotoVehical {
private String type;
public Car(){
}
public Car(String no,String brand,String type){
super(no,brand);
this.type = type;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
@Override
public int calcRent(int days) {
if(this.type.equals("0")){
return 600 * days;
}else if(this.type.equals("1")){
return 500 * days;
}else if(this.type.equals("2")){
return 300 * days;
}else{
System.out.println("您输入的车型不存在！");
return 0;
}
}
}
客车类 Bus.java
package netclass04.abstracts.homework;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/12 - 01 - 12 - 16:28
* @Description: netclass04.abstracts.homework
* @version: 1.0
*/
public class Bus extends MotoVehical {
private int seatCount;
public Bus(){
}
public Bus(String no,String brand,int seatCount){
super(no,brand);
this.seatCount = seatCount;
}
public int getSeatCount() {
return seatCount;
}
public void setSeatCount(int seatCount) {
this.seatCount = seatCount;
}
@Override
public int calcRent(int days) {
if(this.seatCount > 16){
return 1500 * days;
}else{
return 800 * days;
}
}
}
卡车类 Truck.java
package netclass04.abstracts.homework;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 14:50
* @Description: netclass04.abstracts.homework
* @version: 1.0
*/
public class Truck extends MotoVehical {
//吨位
private int weight;
public Truck(String no,String brand,int weight){
super(no,brand);
this.weight = weight;
}
@Override
public int calcRent(int days) {
return 50 * days * this.weight;
}
}
测试类 MotoVehicalTest.java
package netclass04.abstracts.homework;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/12 - 01 - 12 - 16:30
* @Description: netclass04.abstracts.homework
* @version: 1.0
*/
public class MotoVehicalTest {
public static void main(String[] args) {
// MotoVehical moto = new MotoVehical();
// Car car = new Car("豫A 8888888","别克","0");
// int total1 = car.calcRent(5);
// System.out.println("租金为：" +total1);
// Bus bus = new Bus("豫A 6666666","金杯",16);
// int total2 = bus.calcRent(5);
// System.out.println("租金为：" +total2);
MotoVehical[] motoArray = new MotoVehical[5];
//String[] arrays = new String[4];
motoArray[0] = new Car("豫A 00099999","宝马550i","1");
motoArray[1] = new Car("豫B 00088888","宝马550i","1");
motoArray[2] = new Car("豫C 00066666","别克林荫大道","2");
motoArray[3] = new Bus("豫D 00011111","金龙",34);
motoArray[4] = new Truck("豫E 000333333","东方红",50);
// int totalRent = 0;
// for(int i = 0; i<motoArray.length;i++){
// totalRent += motoArray[i].calcRent(5);
// }
int totalRent = MotoVehicalTest.calcRent(motoArray,5);
System.out.println("租5天的总租金是：" + totalRent);
}
public static int calcRent(MotoVehical[] motoArray,int days){
int totalRent = 0;
for(int i = 0; i<motoArray.length;i++){
totalRent += motoArray[i].calcRent(days);
}
return totalRent;
}
}
五、答疑，主要是关于Object对象、抽象类的使用、instanceof的使用、向上转型和向下转型的理解。
1、Object对象的使用
package netclass05.demo;
import java.util.Objects;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 17:17
* @Description: netclass05
* @version: 1.0
*/
public class ObjectTest /*extends Object*/ {
private String name;
private int age;
public ObjectTest(){
// super();
}
public ObjectTest(String name,int age){
this.name = name;
this.age = age;
}
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;
}
@Override
public String toString() {
return "ObjectTest{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
ObjectTest that = (ObjectTest) o;
return age == that.age &&
Objects.equals(name, that.name);
}
@Override
public int hashCode() {
return Objects.hash(name, age);
}
public static void main(String[] args) {
// 需求：想打印出对象的内容
ObjectTest ot = new ObjectTest("张飞",18);
ObjectTest ot2 = new ObjectTest("张飞",18);
System.out.println(ot);
// System.out.println(ot == ot2);
// System.out.println(ot.equals(ot2));
// System.out.println(ot.getClass().getName());
// System.out.print(ot);
// ot.setName("张飞");
// ot.setAge(18);
// System.out.println(ot.getName());
// System.out.println(ot.getAge());
//instanceof的用法 ： 判断一个对象是否是某个类的实例
if(ot instanceof ObjectTest){
System.out.println("yes");
}else{
System.out.println("no");
}
}
}
2、instanceof的使用
package netclass05.demo;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 17:41
* @Description: netclass05.demo
* @version: 1.0
*/
public class A {
public void print(){
System.out.println("我是A... ...");
}
}
package netclass05.demo;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 17:41
* @Description: netclass05.demo
* @version: 1.0
*/
public class B extends A {
public void print(){
System.out.println("我是B... ...");
}
public static void main(String[] args) {
A a = new A();
//向下转型
B b = (B)a;
b.print();
}
}
3、抽象类的使用、向上转型和向下转型的理解
父类 AbstractTest.java
package netclass05.demo;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 17:31
* @Description: netclass05.demo
* @version: 1.0
*/
/**
* 定义一个人类
*/
public abstract class AbstractTest {
private String name;
private int age;
//基本工资
private double basicSalary;
public AbstractTest() {
}
public AbstractTest(String name, int age) {
this.name = name;
this.age = age;
}
public AbstractTest(String name, int age,double basicSalary) {
this.name = name;
this.age = age;
this.basicSalary = basicSalary;
}
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 double getBasicSalary() {
return basicSalary;
}
public void setBasicSalary(double basicSalary) {
this.basicSalary = basicSalary;
}
//定义一个计算工资的方法
public abstract double getSalary();
}
子类 Worker.java
package netclass05.demo;
/**
* @Auther: Yu Panpan
* @Date: 2022/1/14 - 01 - 14 - 17:32
* @Description: netclass05.demo
* @version: 1.0
*/
/**
* 工人类
*/
public class Worker extends AbstractTest {
//绩效工资
private double kpiSalary;
public Worker(){
}
public Worker(String name,int age,double kpiSalary){
super(name,age);
this.kpiSalary = kpiSalary;
}
public double getKpiSalary() {
return kpiSalary;
}
public void setKpiSalary(double kpiSalary) {
this.kpiSalary = kpiSalary;
}
@Override
public double getSalary() {
//基本工资+绩效工资
return super.getBasicSalary() + this.getKpiSalary();
}
public static void main(String[] args) {
//向上转型：子类向父类转化，会自动转化
AbstractTest at = new Worker();
//向下转型：父类向子类转化，需要强制转化，而且可能会出现问题
// AbstractTest at2 = new AbstractTest();//错误的
}
}
