1、设计四个类,分别是:(知识点:抽象类及抽象方法)
(1)Shape表示图形类,有面积属性area、周长属性per,颜色属性color,有两个构造方法(一个是默认的、一个是为颜色赋值的),还有3个抽象方法,分别是:getArea计算面积、getPer计算周长、showAll输出所有信息,还有一个求颜色的方法getColor。
(2)2个子类:
1)Rectangle表示矩形类,增加两个属性,Width表示长度、height表示宽度,重写getPer、getArea和showAll三个方法,另外又增加一个构造方法(一个是默认的、一个是为高度、宽度、颜色赋值的)。
2)Circle表示圆类,增加1个属性,radius表示半径,重写getPer、getArea和showAll三个方法,另外又增加两个构造方法(为半径、颜色赋值的)。
(3)一个测试类PolyDemo,在main方法中,声明创建每个子类的对象,并调用2个子类的showAll方法。
2、Cola公司的雇员分为以下若干类:(知识点:多态)
(1) ColaEmployee :这是所有员工总的父类,属性:员工的姓名,员工的生日月份。
方法:getSalary(int month) 根据参数月份来确定工资,如果该月员工过生日,则公司会额外奖励100 元。
(2) SalariedEmployee : ColaEmployee 的子类,拿固定工资的员工。
属性:月薪
(3) HourlyEmployee :ColaEmployee 的子类,按小时拿工资的员工,每月工作超出160 小时的部分按照1.5 倍工资发放。
属性:每小时的工资、每月工作的小时数
(4) SalesEmployee :ColaEmployee 的子类,销售人员,工资由月销售额和提成率决定。
属性:月销售额、提成率
(5) 定义一个类Company,在该类中写一个方法,调用该方法可以打印出某月某个员工的工资数额,写一个测试类TestCompany,在main方法,把若干各种类型的员工放在一个ColaEmployee 数组里,并单元出数组中每个员工当月的工资。
3、利用接口实现动态的创建对象:(知识点:接口 )
(1)创建4个类
1苹果
2香蕉
3葡萄
4园丁
(2)在三种水果的构造方法中打印一句话.
以苹果类为例
class apple
{
public apple()
{
System.out.println(“创建了一个苹果类的对象”);
}
}
(3)类图如下:
(4)要求从控制台输入一个字符串,根据字符串的值来判断创建三种水果中哪个类的对象。
运行结果如图:
package itheima01.com;
public abstract class Shape {
double area;
double per;
String color;
public Shape(){
}
public Shape(String color){
this.color = color;
}
public abstract double getArea();
public abstract double getPer();
public abstract void showAll();
public String getColor(){
return this.color;
}
}
package itheima01.com;
public class Rectangle extends Shape{
int weidth;
int height;
public Rectangle() {
}
public Rectangle(int weidth,int height,String color){
super(color);
this.weidth = weidth;
this.height = height;
}
public double getArea() {
this.area = weidth * height;
return this.area;
}
public double getPer() {
this.per = 2 * (weidth + height);
return this.per;
}
public void showAll() {
System.out.println("该矩形长为"+this.weidth+",宽为"+this.height+",周长为"+this.getPer()+",面积为"+this.getArea()+",颜色为"+this.getColor());
}
}
package itheima01.com;
public class Circle extends Shape {
double radius;
double pi = Math.PI;
public Circle(){
}
public Circle(double radius,String color){
super(color);
this.radius = radius;
}
public double getArea() {
double area =pi * radius *radius;
return area;
}
public double getPer() {
double per = 2 * pi * radius;
return per;
}
public void showAll() {
System.out.println("半径为"+this.radius+"的圆,周长为"+this.getPer()+",面积为"+this.getArea()+",颜色为"+this.getColor());
}
}
package itheima01.com;
public class PolyDemo {
public static void main(String[] args) {
Rectangle r = new Rectangle(8,9,"brown");
Circle c = new Circle(10,"pink");
r.showAll();
c.showAll();
}
}
2.package itheima01.com;
public class ColaEmployee {
String name;
int month;
public ColaEmployee() {
}
public ColaEmployee(String name, int month) {
this.name = name;
this.month = month;
}
public double getSalary(int month) {
return 0;
}
}package itheima01.com;
public class SalariedEmployee extends ColaEmployee {
double monSalary;
public SalariedEmployee(String name, int month, double monSalary) {
super(name, month);
this.monSalary = monSalary;
}
public double getSalary(int month) {
if (super.month == month) {
return monSalary + 100;
} else {
return monSalary;
}
}
}package itheima01.com;
public class HourlyEmployee extends ColaEmployee {
private int hourSalary;
private int hourNum;
public HourlyEmployee(String name, int month, int hourSalary, int hourNum) {
super(name, month);
this.hourSalary = hourSalary;
this.hourNum = hourNum;
}
public double getSalary(int month) {
if (super.month == month) {
if (hourNum > 160) {
return hourSalary * 160 + hourSalary * (hourNum - 160) * 1.5 + 100;
} else {
return hourSalary * hourNum + 100;
}
} else {
if (hourNum > 160) {
return hourSalary * 160 + hourSalary * (hourNum - 160) * 1.5;
} else {
return hourSalary * hourNum;
}
}
}
}package itheima01.com;
public class SalesEmployee extends ColaEmployee {
private int monthSales;
private double royaltyRate;
public SalesEmployee(String name, int month, int monthSales, double royaltyRate) {
super(name, month);
this.monthSales = monthSales;
this.royaltyRate = royaltyRate;
}
public double getSalary(int month) {
if (super.month == month) {
return monthSales * royaltyRate + 100;
} else {
return monthSales * royaltyRate;
}
}
}package itheima01.com;
public class TestCompany {
public static void main(String[] args) {
ColaEmployee[] z = {
new SalariedEmployee("员工: 王二麻子", 5, 12300),
new HourlyEmployee("员工: 张三", 9, 140, 360),
new SalesEmployee("员工 :李四", 7, 873200, 0.25)
};
for (int i = 0; i <z.length; i++) {
new Company().getSalary(z[i],8);
}
}
}package itheima01.com;
public class Company {
public void getSalary(ColaEmployee k,int month) {
System.out.println(k.name + "在" + month + "月的月薪为" + k.getSalary(month)+"元");
}
}
3.package itheima01.com;
public interface Fruit {
void apple();
void banana();
void orange();
}
package itheima01.com;
public class apple implements Fruit{
public void apple(){
System.out.println("创建了一个苹果类的对象");
}
@Override
public void banana(){
}
@Override
public void orange(){
}
}
package itheima01.com;
public class banana implements Fruit {
public void banana(){
System.out.println("创建了一个香蕉类的对象");
}
@Override
public apple(){
}
@Override
public orange(){
}
}
package itheima01.com;
import java.util.*;
public class Text {
public static void main(String[]args){
Fruit b=new banana();
Scanner input=new Scanner (System.in);
System.out.println("请输入您要创建的类:");
String attr=input.nextLine();
if (attr.equals("banana")){
Fruit fruit =new banana();
fruit.banana();
}
else if (attr.equals("orange")){
Fruit fruit =new orange();
fruit.orange();
}
else if (attr.equals("apple")){
Fruit fruit =new apple();
fruit.apple();
}
else System.out.println("输入有误");
}
}
package itheima01.com;
public class orange implements Fruit {
public void orange(){
System.out.println("创建了一个橙子的对象");
}
@Override
public void apple(){
}
@Override
public void banana(){
}
}
![](https://img2020.cnblogs.com/blog/1962968/202005/1962968-20200521112508275-822769611.png)
![](https://img2020.cnblogs.com/blog/1962968/202005/1962968-20200521112523425-78340329.png)
![](https://img2020.cnblogs.com/blog/1962968/202005/1962968-20200521112532867-1548925254.png)