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();
    }

}

color推荐 java java的color类_color推荐 java

 

 

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);
        }
    }
}

color推荐 java java的color类_构造方法_02

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:

color推荐 java java的color类_子类_03

(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:

 

color推荐 java java的color类_System_04

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!");
    }
}

color推荐 java java的color类_构造方法_05