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。
package op;
public abstract class Shape {
protected double area;
protected double per;
protected String color;
public Shape() {
}
public Shape(String color) {
this.color = color;
}
public abstract void getArea();
public abstract void getPer();
public abstract void showAll();
}
package op;
public class Rectangle extends Shape {
double width;
double height;
public Rectangle() {
}
public Rectangle(double width, double height, String color) {
super();
this.width = width;
this.height = height;
this.color = color;
}
public void getArea() {
area = width * height;
}
public void getPer() {
per = (width + height) * 2;
}
public void showAll() {
System.out.println("矩形面积为:" + area + ",周长为:" + per+",颜色:"+color);
}
}
package op;
public class Circle extends Shape {
double radius;
public Circle() {
}
public Circle(double radius, String color) {
this.color = color;
this.radius = radius;
}
public void getArea() {
area = radius * radius * 3.14;
}
public void getPer() {
per = 2 * radius * 3.14;
}
public void showAll() {
System.out.println("圆的面积为:" + area + ",周长为:" + per+",颜色:"+color);
}
}
package op;
public class PolyDemo {
public static void main(String[] args) {
// TODO Auto-generated method stub
Shape c = new Circle(4,"black");
Shape r = new Rectangle(5,8,"yellow");
c.getArea();
c.getPer();
c.showAll();
r.getArea();
r.getPer();
r.showAll();
}
}
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。
package op;
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 op;
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 op;
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 op;
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 op;
public class Company {
public void getSalary(ColaEmployee c,int month) {
System.out.println(c.name + "在" + month +
"月的月薪为" + c.getSalary(month)+"元");
}
}
package op;
public class TestCompany {
public static void main(String[] args) {
// TODO Auto-generated method stub
ColaEmployee[] cel = {
new SalariedEmployee("拿固定工资的员工", 7, 56000),
new HourlyEmployee("按小时拿工资的员工", 6, 200, 330),
new SalesEmployee("销售人员", 4, 7000000,0.5)
};
for (int i = 0; i < cel.length; i++) {
new Company().getSalary(cel[i],6);
}
}
}
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 op;
public interface Yuanding {
void apple();
void banana();
void putao();
}
package op;
public class Apple implements Yuanding {
public void apple() {
// TODO Auto-generated method stub
System.out.println("创建了一个苹果类的对象");
}
public void banana() {
}
public void putao() {
}
}
package op;
public class Banana implements Yuanding{
public void banana() {
// TODO Auto-generated method stub
System.out.println("创建了一个香蕉类的对象");
}
public void apple() {
}
public void putao() {
}
}
package op;
public class Putao implements Yuanding{
public void putao() {
// TODO Auto-generated method stub
System.out.println("创建了一个葡萄类的对象");
}
public void banana() {
}
public void apple() {
}
}
package op;
import java.util.*;
public class Test {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input=new Scanner(System.in);
System.out.println("请输入您要创建的类:");
String a=input.nextLine();
if(a.equals("apple")) {
Yuanding yuanding=new Apple();
yuanding.apple();
}
else if(a.equals("banana")) {
Yuanding yuanding=new Banana();
yuanding.banana();
}
else if(a.equals("putao")) {
Yuanding yuanding=new Putao();
yuanding.putao();
}
else System.out.println("输入有误!");
}
}