1、精選優(yōu)質(zhì)文檔-傾情為你奉上/定義一個(gè)抽象基類Shape，其中包含area方法abstract class Shape public abstract double area();/定義Cirele并且繼承Shape類，實(shí)現(xiàn)area方法class Circle extends Shapeprivate double r;public Circle(double r)this.r = r;public double area()return Math.PI*r*r;/定義Rectangle并且繼承Shape類，實(shí)現(xiàn)area方法，并且對(duì)其進(jìn)行重載class Rectangle extends Sha

2、peprivate double r;private double length;public Rectangle(double r, double length)this.r = r;this.length = length;public double area()double temp;temp = 2 * Math.PI * r * length;return temp + 2 * Math.PI * r * r;public double area(double r, double length)double temp;temp = 2 * Math.PI * r * length;r

3、eturn temp + 2 * Math.PI * r * r;/定義MyTest作為測試類public class MyTest public static void main(String args) Circle d=new Circle(2);Rectangle s=new Rectangle(2, 2);System.out.println(d.area();System.out.println(s.area();System.out.println(s.area(3, 3);import java.util.*;class Mydateprivate Calendar date

4、= Calendar.getInstance();public void setTime(int hour, int minute, int second)Date temp= new Date();Temp.sethous(hour);Temp.setminutes(minute);Temp.setseconds(second);date.setTime(temp);public void setDate(int year, int month, int day)date.set(year, month-1, day);public String getNowDate()return dat

5、e.get(Calendar.YEAR) + "年" + (date.get(Calendar.MONTH )+1) + "月" + date.get(Calendar.DAY_OF_MONTH) + "日"public String getNowTime()return date.get(Calendar.HOUR) + ":" + date.get(Calendar.MINUTE ) + ":" + date.get(Calendar.SECOND );public class Testpublic static void main(String args)Mydate my=new Mydate();System.out.println(my.getNowDate();System.out.println(my.getNowTime();my.setDate(2012, 9, 9);my.setTime(1,