初学java之接口基础

 1 /*

 2 长城牌电视机

 3 联想奔月5008PC机

 4 */

 5 

 6 

 7  package st;

 8  //接口回调实例

 9  interface ShowMessage

10  {

11    void 显示商标 (String s);

12  }

13  class TV implements ShowMessage

14  {

15      public void 显示商标(String s)

16      {

17       System.out.println(s); 

18      }

19  }

20  class PC implements ShowMessage

21  {

22      public void 显示商标 (String s)

23      {

24       System.out.println(s);

25      }

26  }

27  public class example_1

28  {

29    public static void main(String args[])

30    {

31        ShowMessage sm;   //声明接口变量

32        sm=new TV();   //接口变量中存放对象的引用

33        sm.显示商标("长城牌电视机");  //接口回调

34        sm=new PC();    

35        sm.显示商标("联想奔月5008PC机");       

36    }  

37  }

接口回调

 

 1 /*

 2  * 对于接口理解的一个列子

 3  * 详情请关注龚细军（Gxjun）的博客

 4  * */ 

 5  package st;

 6  

 7   abstract class Motorvehicles

 8  {

 9    abstract void brake();

10  }

11 //  接口1

12  interface ControlTemperature

13  {

14     void ControlAirTemperature();

15  }

16  //接口2

17  interface MonenyFare

18  {

19    void Charge();

20  }

21  class Bus extends Motorvehicles implements MonenyFare

22  {

23      void brake()

24      {

25        System.out.println("公交车来啦！,嘟嘟");

26      }

27     public void Charge()

28     {

29      System.out.println("公交车收费为5毛");

30     }

31  }

32  class taxi extends Motorvehicles implements MonenyFare , ControlTemperature

33  {

34     

35      void brake()

36      {

37        System.out.println("taxi来啦！,嘟嘟");

38      }

39      public void Charge()

40     {

41      System.out.println("taxi收费为5毛");

42     }

43     public void ControlAirTemperature()

44     {

45       System.out.println("taxi执行温度控制开关！");        

46     }

47  }

48  class Cinema implements MonenyFare , ControlTemperature

49  {

50         public void Charge()

51         {

52          System.out.println("电影院收费为5毛");

53         }

54         public void ControlAirTemperature()

55         {

56           System.out.println("电影院执行温度控制开关！");        

57         }

58  }

59 public class example_1 {

60   public  static void main(String args[])

61    {

62       Bus myBus = new Bus();

63       taxi mytaxi = new taxi();

64       Cinema mycinema = new Cinema();

65       myBus.brake();

66       myBus.Charge();

67       mytaxi.brake();

68       mytaxi.Charge();

69       mytaxi.ControlAirTemperature();

70       mycinema.Charge();

71       mycinema.ControlAirTemperature();

72    }

73 }

View Code

 

  

/*

公交车来啦！,嘟嘟

公交车收费为5毛

taxi来啦！,嘟嘟

taxi收费为5毛

taxi执行温度控制开关！

电影院收费为5毛

电影院执行温度控制开关！

*/

 接口与多态：

 1 /*

 2 11.23 22.78

 3 a和b的算术平均值为：17.005000000000003

 4 a和b的几何平均值为:15.99435525427643

 5 

 6 */

 7 

 8 

 9   package st ;

10   import java.util.Scanner;

11   interface c_average

12   {

13     public double average(double a, double b);

14   }

15 //  求算术平均值

16   class A implements c_average

17   {

18       public double average(double a , double b)

19       { 

20          return (a+b)/2; 

21       }

22   }

23   class B implements c_average

24   {

25       public double average(double a,double b)

26       {

27           return Math.sqrt(a*b);

28       }

29   }

30   public class example_1

31   {

32       public static void main(String args[])

33       {

34           Scanner reader=new Scanner(System.in);

35           double a,b;

36           a=reader.nextDouble();

37           b=reader.nextDouble();

38           A  mya = new A();

39           System.out.println("a和b的算术平均值为："+mya.average(a, b));

40           B myb=new B();

41           System.out.println("a和b的几何平均值为:"+myb.average(a,b));

42       }

43   }

44  

接口与多态