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：

package y;
// 图形接口 
public interface Shape {
    double getArea();
}

package y;
//圆类重写图形接口，重写面积方法
public class Circle implements Shape {
        double r;     
        public Circle(double r){
            this.r=r;
        }
    @Override
    public double getArea() {
        // TODO Auto-generated method stub
          return Math.PI*r*r;
    }

}

package y;
//矩形类重写图形接口，重写面积方法
public class Rectangle implements Shape {
        double width;
        double length;
        public Rectangle(double width, double length) {
            this.width = width;
            this.length = length;
        }      
    @Override
    public double getArea() {
        // TODO Auto-generated method stub        
        return  width * length;
    }
    

}

package y;
//圆类重写图形接口，重写面积方法
public class Trapezoid implements Shape{
    double s;
    double  x;
    double  h;
    public Trapezoid(double s, double x,double h) {
    this.s =s;
    this.x =x;
    this.h = h;
        }      
    @Override
    public double getArea() {
        // TODO Auto-generated method stub        
        return  (s+x)*h/2.0;
    }

}

package y;
//三角形类重写图形接口，重写面积方法
public class Triangle implements Shape {
    double a;
    double b;
    double c;
    public Triangle(double a,double b,double c){
        this.a=a;
        this.b=b;
        this.c=c;
    }
    @Override
    public double getArea() {
        // TODO Auto-generated method stub
        double p=(a+b+c)/2;
        return Math.sqrt(p*(p-a)*(p-b)*(p-c));
    }

}

package y;
//正方形类继承矩形类
public class Zheng extends Rectangle {
     public Zheng(double side) {
            super(side, side);
        }
    @Override
    public double getArea() {
        // TODO Auto-generated method stub
        return width * width;
    }

}

package y;
//柱类，包括构造方法，求体积方法，和换底方法
public class Cone {
     Shape shape;
        double high;
        
        public Cone(Shape shape, double high) {
            this.shape = shape;
            this.high = high;
        }
        public double getVolume() {
            return shape.getArea()*high;
        }
        public void setShape(Shape shape)
        {
            this.shape=shape;
        }
}

package y;

import java.util.Scanner;
//工厂类
public class Foctory {
     public Shape getShape(char c) {
         Scanner reader = new Scanner(System.in);
         Shape shape = null;
         switch (c) {
         case 'R':
             System.out.println("请输入矩形的长和宽、柱体的高");
             shape = new Rectangle(reader.nextInt(), reader.nextDouble());
             break;
         case 'S':
             System.out.println("请输入三角形的边柱体的高");
             shape = new Triangle(reader.nextDouble(), reader.nextDouble(), reader.nextDouble());
             break;
         case 'C':
             System.out.println("请输入圆半径,柱体的高");
             shape = new Circle(reader.nextDouble());
             break;
         case 'T':
             System.out.println("请输入梯形的上底下底和高");
             shape = new Trapezoid(reader.nextDouble(), reader.nextDouble(), reader.nextDouble());
             break;
         case 'Z':
             System.out.println("请输入正方形的边长，柱体的高");
             shape = new Zheng(reader.nextDouble());
             break;
         }
         return shape;
 }
}

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