1、设计个类,分别是:(知识点:抽象类及抽象方法)

1Shape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

22个子类:

1Rectangle表示矩形类,增加两个属性,Width表示长度、height表示宽度,重写getPergetAreashowAll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)。

2Circle表示圆类,增加1个属性,radius表示半径,重写getPergetAreashowAll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。

(1)

 

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 a();
	    public abstract void b();
	    public abstract void showAll();
	}

 

 (2)

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 a(){
	        area = width*height;
	    }
	    public void b(){
	        per = (width+height)*2;
	    }
	    public void showAll(){
	        System.out.println("矩形的面积为:"+area+",周长为:"+per+",颜色为:"+color);
	    }
	}

 

public class Circle extends Shape {
    double radius;
    public Circle(){
        
    }
    public Circle(double radius,String color){
        this.color = color;
        this.radius = radius;
    }
    public void a(){
        area = radius*radius*3.14;
    }
    public void b(){
        per = 2*radius*3.14;
    }
    public void showAll(){
        System.out.println("圆的面积为:"+area+",周长为:"+per+",颜色:"+color);
    }
} 

(3)

public class PolyDemo {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Circle circle = new Circle(4,"break");
        Rectangle rectangle = new Rectangle(6,9,"yellow");
        circle.a();
        circle.b();
        circle.showAll();
        rectangle.a();
        rectangle.b();
        rectangle.showAll();
    }

}

  

2Cola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,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。

(1)

 

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;
    }
}

 

(2)

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;
        }
    }
    
    }

(3)

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;
        }
    }
    }
}

(4)

public class SalesEmployee extends ColaEmployee {
    private int monthSales;
    private double royatyRate;
    public SalesEmployee(String name,int month,int monthSales,double royaltyRate){
        super(name,month);
        this.monthSales = monthSales;
        this.royatyRate = royaltyRate;
    }
    public double getSalary(int month){
        if(super.month==month){
            return monthSales*royatyRate+100;
        }else{
            return monthSales*royatyRate;
        }
    }
}

(5)

public class Company {
    public void getSalary(ColaEmployee a,int month){
        System.out.println(a.name+"在"+month+"月的月薪为"+a.getSalary(month)+"元");
    }

}

  

public class TestCompany {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        ColaEmployee[] ae1={
                new SalariedEmployee("SalariedEmployee",5,15000),
                new HourlyEmployee("hourlyEmplotee",5,50,300),
                new SalesEmployee("salesEmployee",4,50000,0.4)
        };
        for(int i=0;i<ae1.length;i++){
            new Company().getSalary(ae1[i],5);
        }
    }

}

 

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:

 

 

 

public interface Fruit {

}
public class Apple implements Fruit {
    public Apple(){
        System.out.println("创建了一个苹果类对象");
    }
} 
public class Banana implements Fruit {
    public Banana(){
        System.out.println("创建了一个香蕉类对象");
    }
}
public class Grape implements Fruit {
    public Grape(){
        System.out.println("创建了一个葡萄类对象");
    }
}

  

import java.util.Scanner;

public class Gardener {
	 private Scanner in;

	public void creater() {
	        String m = "";
	        in = new Scanner(System.in);
	        m = in.nextLine();
	        if(m.equals("苹果")){
	            new Apple();
	        }else if(m.equals("香蕉")){
	            new Banana();
	        }else if(m.equals("葡萄")){
	            new Grape();
	        }else{
	            System.out.println("请输入正确的对象");
	        }

	    }

	    }

  

public class FruitTest {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        new Gardener().creater();
    }

}