JAVA例8.9-例8.15及实验35-38.doc

例8.9运算符instanceof及getName()、getSuperclass()方法的使用。/filename Person.javapublic class Person /定义person类static int count=0;protected String name;protected int age;public Person(String n1,int a1)name=n1;age=a1;this.count+; /调用父态的静态变量public String toString()return +,+this.age;public void display()System.out.print(本类名=+this.getClass().getName()+;);System.out.println( 父类名=+this.getClass().getSuperclass().getName();System.out.print(Person.count=+this.count+ );System.out.println( Student.count=+Student.count+ );Object obj=this;if(obj instanceof Student) /判断对象属于哪个类System.out.println(obj.toString()+是Student类对象。);else if(obj instanceof Person)System.out.println(obj.toString()+是Person类对象。);class Student extends Person /子类Student继承父类Person，且是主类但不是public类static int count=0; /隐藏了父类的countprotected String dept;protected Student(String n1,int a1,String d1)super(n1,a1); /调用父类的构造方法dept=d1;this.count+; /调用子类的静态变量public String toString() /覆盖父类的同名方法 return super.toString()+,+dept; /调用父类的同名方法public void display()super.display();System.out.println(super.count=+super.count);System.out.println(this.count=+this.count);public static void main(String args)Person per=new Person(王涛,23);per.display();Student stu=new Student(张三,22,计算机系);stu.display();程序运行结果及其分析：例8.10 抽象类的应用举例，定义一个形状抽象类Shape，以该抽象类为父类派生出圆形子类Circle和矩形子类Rectangle。/filename App8_10.javaabstract class Shape /定义形状抽象类Shapeprotected String name;public Shape(String xm) /抽象类中的一般方法，本方法是构造方法name=xm;System.out.print(名称：+name);abstract public double getArea(); /声明抽象方法abstract public double getlength(); /声明抽象方法class Circle extends Shape /定义继承自Shape的圆形子类Circleprivate final double PI=3.14;private double radius;public Circle(String shapeName,double r) /构造方法super(shapeName);radius=r;public double getArea() /实现抽象类中的getArea()方法return PI*radius*radius;public double getlength() /实现抽象类中的getlength()方法return 2*PI*radius;class Rectangle extends Shapeprivate double width;private double height;public Rectangle(String shapeName,double width,double height)super(shapeName);this.width=width;this.height=height;public double getArea()return width*height;public double getlength()return 2*(width+height);public class App8_10public static void main(String args)Shape rect=new Rectangle(长方形,6.5,10.3);System.out.print(; 面积=+rect.getArea()+ ;周长=+rect.getlength()+n);Shape circle=new Circle(圆,10.2);System.out.print(; 面积=+circle.getArea()+ ;周长=+circle.getlength();程序运行结果及其分析：例8.11 利用形状接口IShape建造类。/filename App8_11.javainterface IShapefinal double PI=3.14;abstract double getArea();abstract double getlength();class Circle implements IShapedouble radius;public Circle(double r)radius=r;public double getArea()return PI*radius*radius;public double getlength()return 2*PI*radius;class Rectangle implements IShapeprivate double width;private double height;public Rectangle(double width,double height)this.width=width;this.height=height;public double getArea()return width*height;public double getlength()return 2*(width+height);public class App8_11public static void main(String args)IShape circle=new Circle(5.0);System.out.print(圆的面积=+circle.getArea()+ ; 周长=+circle.getlength()+n);Rectangle rect=new Rectangle(6.5,10.8);System.out.print(矩形面积=+rect.getArea()+ ; 周长=+rect.getlength();例8.12 接口的继承。/filename Cylinder.javainterface Face1final double PI=3.14;abstract double area();interface Face2abstract void setColor(String c);interface Face3 extends Face1,Face2abstract void volume();public class Cylinder implements Face3private double radius;private int height;protected String Color;public Cylinder(double r,int h)radius=r;height=h;public double area()return PI*radius*radius;public void setColor(String c)Color=c;System.out.println(颜色：+Color);public void volume()System.out.println(圆柱体体积：+area()*height);public static void main(String args)Cylinder volu=new Cylinder(3.0,2);volu.setColor(红色);volu.volume();例8.13 利用接口实现类的多重继承。/filename Cylinder.javainterface Face1final double PI=3.14;abstract double area();interface Face2abstract void volume();public class Cylinder implements Face1,Face2private double radius;private int height;public Cylinder(double r,int h)radius=r;height=h;public double area()return PI*radius*radius;public void volume()System.out.println(圆柱体体积：+area()*height);public static void main(String args)Cylinder volu=new Cylinder(5.0,2);volu.volume();例8.14内部与外部的访问规则。/filename Group.javapublic class Groupprivate int age;public class StudentString name;public Student(String n,int a)name=n;age=a;public void output()System.out.println(姓名:++; 年龄：+age);public void output()Student stu=new Student(刘洋,24);stu.output();public static void main(String args)Group g=new Group();g.output();实验35抽象类/filename ChouXiang.javaabstract class Shapeabstract public float Area();abstract public void printArea();class Rectangle extends Shapeint width;int length;public Rectangle(int newWidth,int newLength)width=newWidth;length=newLength;public float Area()return width*length;public void printArea()System.out.println(矩形的面积是+Area();class Circle extends Shapefinal float pi=3.14F;int radius;public Circle(int newRadius)radius=newRadius;public float Area()return pi*radius*radius;public void printArea()System.out.println(圆的面积是+Area();class ChouXiangpublic static void main(String args)Rectangle s1=new Rectangle(3,4);Circle s2=new Circle(2);s1.printArea();s2.printArea();实验37 使用JDK参考文档编写java程序。/UseJDK.javaimport java.lang.Math;public class UseJDKpublic static void main(String args)int a;a=(int)(Math.random()*10);System.out.println(a=+a+的平方根为+Math.sqrt(a);实验38 为java程序生成文档。/GdufStudent.java/*这个程序定义了一个学生类，类中有三个属性，七个方法，可以调用introduce()方法，显示学生的姓名、年龄和系别。*/public class GdufStudent/*公共属性，字符串型，学校的名字*/public String School;private String name;private int age;privat