第9次作业--接口及接口回调

题目：

利用接口和接口回调，实现简单工厂模式，当输入不同的字符，代表相应图形时，利用工厂类获得图形对象，再计算以该图形为底的柱体体积。

代码：

1 package y;
2 // 图形接口 
3 public interface Shape {
4     double getArea();
5 }

 1 package y;
 2 //圆类重写图形接口，重写面积方法
 3 public class Circle implements Shape {
 4         double r;     
 5         public Circle(double r){
 6             this.r=r;
 7         }
 8     @Override
 9     public double getArea() {
10         // TODO Auto-generated method stub
11           return Math.PI*r*r;
12     }
13 
14 }

 1 package y;
 2 //矩形类重写图形接口，重写面积方法
 3 public class Rectangle implements Shape {
 4         double width;
 5         double length;
 6         public Rectangle(double width, double length) {
 7             this.width = width;
 8             this.length = length;
 9         }      
10     @Override
11     public double getArea() {
12         // TODO Auto-generated method stub        
13         return  width * length;
14     }
15     
16 
17 }

 1 package y;
 2 //圆类重写图形接口，重写面积方法
 3 public class Trapezoid implements Shape{
 4     double s;
 5     double  x;
 6     double  h;
 7     public Trapezoid(double s, double x,double h) {
 8     this.s =s;
 9     this.x =x;
10     this.h = h;
11         }      
12     @Override
13     public double getArea() {
14         // TODO Auto-generated method stub        
15         return  (s+x)*h/2.0;
16     }
17 
18 }

 1 package y;
 2 //三角形类重写图形接口，重写面积方法
 3 public class Triangle implements Shape {
 4     double a;
 5     double b;
 6     double c;
 7     public Triangle(double a,double b,double c){
 8         this.a=a;
 9         this.b=b;
10         this.c=c;
11     }
12     @Override
13     public double getArea() {
14         // TODO Auto-generated method stub
15         double p=(a+b+c)/2;
16         return Math.sqrt(p*(p-a)*(p-b)*(p-c));
17     }
18 
19 }

 1 package y;
 2 //正方形类继承矩形类
 3 public class Zheng extends Rectangle {
 4      public Zheng(double side) {
 5             super(side, side);
 6         }
 7     @Override
 8     public double getArea() {
 9         // TODO Auto-generated method stub
10         return width * width;
11     }
12 
13 }

 1 package y;
 2 //柱类，包括构造方法，求体积方法，和换底方法
 3 public class Cone {
 4      Shape shape;
 5         double high;
 6         
 7         public Cone(Shape shape, double high) {
 8             this.shape = shape;
 9             this.high = high;
10         }
11         public double getVolume() {
12             return shape.getArea()*high;
13         }
14         public void setShape(Shape shape)
15         {
16             this.shape=shape;
17         }
18 }

 1 package y;
 2 
 3 import java.util.Scanner;
 4 //工厂类
 5 public class Foctory {
 6      public Shape getShape(char c) {
 7          Scanner reader = new Scanner(System.in);
 8          Shape shape = null;
 9          switch (c) {
10          case 'R':
11              System.out.println("请输入矩形的长和宽、柱体的高");
12              shape = new Rectangle(reader.nextInt(), reader.nextDouble());
13              break;
14          case 'S':
15              System.out.println("请输入三角形的边柱体的高");
16              shape = new Triangle(reader.nextDouble(), reader.nextDouble(), reader.nextDouble());
17              break;
18          case 'C':
19              System.out.println("请输入圆半径,柱体的高");
20              shape = new Circle(reader.nextDouble());
21              break;
22          case 'T':
23              System.out.println("请输入梯形的上底下底和高");
24              shape = new Trapezoid(reader.nextDouble(), reader.nextDouble(), reader.nextDouble());
25              break;
26          case 'Z':
27              System.out.println("请输入正方形的边长，柱体的高");
28              shape = new Zheng(reader.nextDouble());
29              break;
30          }
31          return shape;
32  }
33 }

package h;

import java.util.Scanner;

import y.Cone;
import y.Foctory;

public class Test {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         while(true){
                Scanner reader = new Scanner(System.in);
                System.out.println("矩形R,三角形S,圆C,梯形T,正方形Z");
                char c = reader.next().charAt(0);
                Foctory f = new Foctory();
                Cone cone = new Cone(f.getShape(c), reader.nextDouble());
                System.out.println(cone.getVolume());
            }

    }

}

运行