第9次作业--接口及接口回调

一、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。

二、源程序

1. Shape.java

package work;

public interface Shape {      //接口
    double getArea();
}

2.Factory.java

package work;
import java.util.*;
public class Factory {//工厂类

     static Shape shape = null;

    public static Shape k(char c) {//根据用户输入字母  判断柱体底面
        switch (c) {
        case 'J':
            System.out.println("矩形柱体高为：");
            shape = new Juxing(4, 5);
            break;
        case 'Z':
            System.out.println("正方形柱体高为：");
            shape = new Zheng(5);
            break;
        case 'S':
            System.out.println("三角形柱体高为：");
            shape = new San(4, 5, 6);
            break;
        case 'Y':
            System.out.println("圆形柱体高为：");
            shape = new Yuan(5, 3.14);
            break;
        case 'T':
            System.out.println("梯形柱体高为：");
            shape = new Tixing(4, 5, 7);
            break;

        }
        return shape;

    }
}

3.Cone.java

package work;

public class Cone {//换㡳 求体积
    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 setRect(Shape shape) {        
        this.shape = shape;
    }

}

4.Jvxing.java

 

package work;

public class Juxing implements Shape {//创建矩形类使用接口
    double width;
    double length;

    public Juxing(double width, double length) {
        this.width = width;
        this.length = length;

    }

    public double getArea() {          //计算矩形面积              
        return width * length;
    }

}

 

 

 

5.Zheng.java

package work;

public class Zheng extends Juxing {//创建矩形子类正方形
    public Zheng(double side) {
        super(side, side);
    }

    public Zheng() {
        super(0, 0);
    }

    public double getArea() {      //计算面积                  
        return width * width;
    }

}

6.San.java

package work;

public class San implements Shape {//创建三角形类使用接口
    double a;
    double b;
    double c;

    public San(double a, double b, double c) {
        this.a = a;
        this.b = b;
        this.c = c;

    }

    public double getArea() {               //计算体积                     
        double p = (a + b + c) / 2;
        return Math.sqrt(p * (p - a) * (p - b) * (p - c));         
    }

}

7.Yuan.java

package work;

public class Yuan implements Shape {//创建圆形类使用接口
    double r;
    double PI = 3.14;

    public Yuan(double r, double PI) {
        this.r = r;
    }

    public double getArea() {         //计算面积     
        return PI * r * r;

    }

}

8.Tixing.java

package work;

public class Tixing implements Shape {//创建梯形类使用接口
    double s;
    double x;
    double h;

    public Tixing(double s, double x, double h) {
        this.s = s;
        this.x = x;
        this.h = h;

    }

    public double getArea() {               //计算体积 
        return (s + x) * h / 2;
    }

}

9.Test.java

package work;

import java.util.Scanner;
import work.Cone;
import work.Factory;

public class Text {

    public static void main(String[] args) {//创建一个主方法

        while (true) {
            Scanner reader = new Scanner(System.in);

            System.out.println("输入对应字母:");
            char c = reader.next().charAt(0);

            Factory factory = new Factory();
            Cone cone = new Cone(factory.k(c), reader.nextDouble());

            System.out.println("体积为：" + cone.getVolume());
        }
    }

}

三、运算结果