您好，请问JAVA语言程序设计两道练习题。谢谢！

Question

1、创建Person接口(即“人”)，它有setData()和getData()方法对“人”属性name、sex和birthday赋值和获得这些属性组成的字符串信息。创建类Student实现Person接口，并对自己的“学生”属性的成员变量sID、speciality设置值和获得它们值所组成的字符串信息。
2、编写程序,求柱体的体积:
（1）、为柱体的底面设计一个接口Geometry，包含计算面积的方法getArea();
（2）、为柱体设计类pillar，要求：
a)有两个成员变量，底面和高度。底面是任何可以计算面积的几何形状。
b)实现构造方法，对成员变量赋值。
c)包含成员方法，计算柱体pillar的体积。
（3）、编写测试类圆形类、矩形类实现Geometry接口，编写测试类Test，分别用圆形、矩形作为柱体的底面，并计算其体积。

Answer 1

第一题有问题：1、创建Person接口(即“人”)，它有setData()和getData()方法对“人”属性name、sex和birthday赋值和获得这些属性组成的字符串信息。问题是：你说要创建一个人（接口），然后里面有方法对人的属性进行赋值？这怎么可能呢，接口是没有成员变量（属性）的，怎么能赋值？接口里只能有常量。第二题可以答一下：package pillar;public class Pillar { private Geometry buttom;private double height;public Pillar() {// TODO Auto-generated constructor stub}public Pillar(Geometry button,double height){this.buttom = button;this.height = height;}public double getVolume(){return this.buttom.getArea()*height;}public Geometry getButtom() {return buttom;}public void setButtom(Geometry buttom) {this.buttom = buttom;}public double getHeight() {return height;}public void setHeight(double height) {this.height = height;}}------------------------------------------------类分割线---------------------------------------------------------package pillar;public interface Geometry { double getArea();}------------------------------------------------类分割线---------------------------------------------------------package pillar;public class Circle implements Geometry { private double r;public Circle() {// TODO Auto-generated constructor stub}public Circle(double r) {this.r = r;}public double getArea() { return Math.PI*r*r;}public double getR() {return r;}public void setR(double r) {this.r = r;}}------------------------------------------------类分割线---------------------------------------------------------package pillar;public class Rectangle implements Geometry { private double width;private double height;public Rectangle() {// TODO Auto-generated constructor stub}public Rectangle(double width, double height) {this.width = width;this.height = height;}public double getArea() { return this.width*this.height;}public double getWidth() {return width;}public void setWidth(double width) {this.width = width;}public double getHeight() {return height;}public void setHeight(double height) {this.height = height;}}------------------------------------------------类分割线---------------------------------------------------------package pillar;public class TestPillar {/** * @param args*/public static void main(String[] args) {Circle c = new Circle(5);Rectangle r = new Rectangle(3,4);Pillar p1 = new Pillar(c,6);Pillar p2 = new Pillar(r,6);System.out.println("圆的体积："+p1.getVolume()+"\t矩形的体积："+p2.getVolume());}}

Answer 2

第一题Person接口import java.util.Date;public interface Person {    public void setData(String sID, String speciality, String name, String sex, Date birthday);    public String getData();                            }Student实现类import java.util.Date;public class Student implements Person {    private String sID;    private String speciality;    private String name;    private String sex;    private Date birthday;            @Override    public void setData(String sID, String speciality, String name, String sex,            Date birthday) {        this.sID = sID;        this.speciality = speciality;        this.name = name;        this.sex = sex;        this.birthday = birthday;    }    @Override    public String getData() {        return "Student [sID=" + sID + ", speciality=" + speciality + ", name="                + name + ", sex=" + sex + ", birthday=" + birthday + "]";    }        }