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 d18; 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 getcolor(); public abstract void showall(); }
package d18; public class Rectangle extends Shape { double Width; double height; public Rectangle() { } public Rectangle(double width, double height, String color) { super(color); 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("面积是" + area + "周长是" + per + "颜色是" + color); } @Override public void getcolor() { // TODO Auto-generated method stub } }
package d18; public class Circle extends Shape { double radius; public void Shape() { } public Circle(double radius, String color) { super(color); this.radius = radius; this.color = color; } @Override public void getarea() { // TODO Auto-generated method stub area = 3.14 * radius * radius; } @Override public void getper() { // TODO Auto-generated method stub per = 3.14 * radius * 2; } @Override public void getcolor() { // TODO Auto-generated method stub } @Override public void showall() { // TODO Auto-generated method stub System.out.println("面积是" + area + "周长是" + per + "颜色是" + color); } }
package d18; public class PolyDemo { public static void main(String[] args) { // TODO Auto-generated method stub Shape a=new Rectangle(5.0,3.0,"黑色"); a.getarea(); a.getper(); a.showall(); Shape b= new Circle(2.0,"白色"); 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。
(2) SalariedEmployee : ColaEmployee 的子类,拿固定工资的员工。
(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。
(4) SalesEmployee :ColaEmployee 的子类,销售人员,工资由月销售额和提成率决定。
(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 d19; public class ColaEmployee { String name; int month; public ColaEmployee() { super(); } public ColaEmployee(String name, int month) { super(); this.name = name; this.month = month; } public double getmoney(int month) { return 0; } }
package d19; public class SalariedEmployee extends ColaEmployee { double money; public SalariedEmployee() { super(); } public SalariedEmployee(String name, int month, double money) { super(name, month); this.money = money; } public double getmoney(int month) { if(super.month==month){ return money+100; }else{ return money; } } }
package d19; public class HourlyEmployee extends ColaEmployee { double hmoney; int hour; public HourlyEmployee() { super(); } public HourlyEmployee(String name, int month, double hmoney, int hour) { super(name, month); this.hmoney = hmoney; this.hour = hour; } public double getmoney(int month) { if (super.month == month) { if (hour > 160) { return hmoney * 160 + (hour - 160) * 1.5 + 100; } else { return hmoney * hour + 100; } } else { if (hour > 160) { return hmoney * 160 + (hour - 160) * 1.5; } else { return hmoney * hour; } } } }
package d19; public class SalesEmployee extends ColaEmployee { int sales; double rate; public SalesEmployee() { super(); } public SalesEmployee(String name, int month, int sales, double rate) { super(name, month); this.sales = sales; this.rate = rate; } public double getmoney(int month) { if (super.month == month) { return sales * rate + 100; } else { return sales * rate; } } }
package d19; public class Company { public void getmoney(ColaEmployee c,int month) { System.out.println(c.name + "在" + month + "月的月薪为" + c.getmoney(month)+"元"); } }
package d19; public class TestCompany { public static void main(String[] args) { // TODO Auto-generated method stub ColaEmployee[] all = { new SalariedEmployee("张三", 5, 9000), // name,month,月薪 new HourlyEmployee("李四", 5, 120, 165), // name,month,时薪,小时数 new SalesEmployee("王五",5,100,2.5)// name,month,月销售额,提成率 }; for (int i = 0; i < all.length; i++) { new Company().getmoney(all[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”);
}
package d20; public interface Fruit { }
package d20; public class apple implements Fruit { public apple() { System.out.println("创建了一个苹果类对象"); } }
package d20; public class banana implements Fruit { public banana() { System.out.println("创建了一个香蕉类对象"); } }
package d20; public class grape implements Fruit { public grape() { System.out.println("创建了一个葡萄类对象"); } }
package d20; import java.util.Scanner; public class gardener { public void creater() { Scanner input = new Scanner(System.in); String a = input.next(); if (a.equals("苹果")) { new apple(); } else if (a.equals("香蕉")) { new banana(); } else if (a.equals("葡萄")) { new grape(); } else { System.out.println("请重新运行"); } } public static void main(String[] args) { new gardener().creater(); } }