java第17次

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。

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();

}

public class Rectangle1 extends Shape {
     double width;
        double height;

        public Rectangle1() {
        }

        public Rectangle1(double width, double height, String color) {
            super();
            this.width = width;
            this.height = height;
            this.color = color;
        }

    @Override
    public void getArea() {
        // TODO Auto-generated method stub
        area = width * height;

    }

    @Override
    public void getPer() {
        // TODO Auto-generated method stub
        per = (width + height) * 2;

    }

    @Override
    public void showAll() {
        // TODO Auto-generated method stub
        System.out.println("矩形面积为：" + area + "，周长为：" + per + ",颜色：" + color);
        
    }

}

public class Circle extends Shape {
     double radius;

     public Circle() {
     }

     public Circle(double radius, String color) {
         this.color = color;
         this.radius = radius;
     }

    @Override
    public void getArea() {
        // TODO Auto-generated method stub
         area = radius * radius * 3.14;

    }

    @Override
    public void getPer() {
        // TODO Auto-generated method stub
         per = 2 * radius * 3.14;

    }

    @Override
    public void showAll() {
        // TODO Auto-generated method stub
         System.out.println("圆的面积为：" + area + "，周长为：" + per + ",颜色：" + color);

    }

}



public class PlayDemo {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
         Shape a = new Circle(6, "red");
         Shape b = new Rectangle1(6,3, "粉色");
         a.getArea();
         a.getPer();
         a.showAll();
         b.getArea();
         b.getPer();
         b.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。

Ÿ 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。

Ÿ 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。

Ÿ 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。

Ÿ 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。

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;
        }
}

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;
        }    
    }

}

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;
        }
    }         
  }

public class SalaesEmployee extends ColaEmployee {
     private int monthSales;
     private double royaltyRate; 
    public SalaesEmployee(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;
        }
    }    

}

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;
        }
    }         
  }

public class SalaesEmployee extends ColaEmployee {
     private int monthSales;
     private double royaltyRate; 
    public SalaesEmployee(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;
        }
    }    

}

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

}

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", 6, 10000),
                    new HourlyEmployee("按小时拿工资的员工", 5, 100, 280),
                    new SalaesEmployee("销售人员", 3, 7000, 0.6)
                    };
            for (int i = 0; i < cel.length; i++) {
                new Company().getSalary(cel[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("创建一个苹果");
    }

}

public class Banana implements Fruit{
    public Banana() {
        System.out.println("创建一个香蕉");
    }

}

public class Grape implements Fruit{
    public Grape() {
        System.out.println("创建一个葡萄");
    }

}

import java.util.Scanner;
public class Gardener {
    public Fruit create() {
        System.out.println("输入：");
        Scanner input = new Scanner(System.in);
        String name = input.next();
        Fruit fruit = null;
        switch(name){
        case "苹果":
            fruit = new Apple();
            break;
        case "香蕉":
            fruit = new Banana();
            break;
        }
        input.close();
        return fruit;
    }


}

public class FruitText {

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

    }

}