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、代码

1.Shape.java

package Thirtenth;
/*
 *一个Shape接口类
 * 
 */
public interface Shape {
    public double getArea();
}

2.Rectiangle.java

package Thirtenth;
/*
 * Rectiangle类使用接口
 * 一个getArea的方法计算面积
 * 
 */
public class Rectiangle implements Shape {
    double a;
    double b;

    public double getA() {
        return a;
    }

    public void setA(double a) {
        this.a = a;
    }

    public double getB() {
        return b;
    }

    public void setB(double b) {
        this.b = b;
    }

    Rectiangle(double a, double b) {
        this.a = a;
        this.b = b;
    }

    Rectiangle() {
        a = 0;
        b = 0;
    }

    @Override
    public double getArea() {
        // TODO Auto-generated method stub
        return a * b;
    }

}

3.Square.java

package Thirtenth;
/*
 * Square类使用接口
 * 一个getArea的方法计算面积
 * 
 */
public class Square extends Rectiangle {

    Square(double side) {
        super(side, side);
    }

    Square() {
        a=0;
    }
    
    public double getArea() {
        // TODO Auto-generated method stub
        return a * a;
    }

}

4.Triangle.java

package Thirtenth;
/*
 * Triangle类使用接口
 * 一个getArea的方法计算面积
 * 
 */
public class Triangle implements Shape {
    double a;
    double b;
    double c;

    public double getA() {
        return a;
    }

    public void setA(double a) {
        this.a = a;
    }

    public double getB() {
        return b;
    }

    public void setB(double b) {
        this.b = b;
    }

    public double getC() {
        return c;
    }

    public void setC(double c) {
        this.c = c;
    }

    Triangle(double a, double b, double c) {
        this.a = a;
        this.b = b;
        this.c = c;
    }

    Triangle() {
        a = 0;
        b = 0;
        c = 0;
    }

    @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));
    }

}

5.Circle.java

package Thirtenth;
/*
 * Circle类使用接口
 * 一个getArea的方法计算面积
 * 
 */
public class Circle implements Shape {
    double r;

    public double getR() {
        return r;
    }

    public void setR(double r) {
        this.r = r;
    }
    
    Circle(double r){
        this.r=r;
    }
    
    Circle(){
        r=0;
    }

    @Override
    public double getArea() {
        // TODO Auto-generated method stub
        return Math.PI*r*r;
    }

}

6.Trapezoid.java

package Thirtenth;
/*
 * Trapezoid类使用接口
 * 一个getArea的方法计算面积
 * 
 */
public class Trapezoid implements Shape {

    double a;
    double b;
    double h;

    public double getA() {
        return a;
    }

    public void setA(double a) {
        this.a = a;
    }

    public double getB() {
        return b;
    }

    public void setB(double b) {
        this.b = b;
    }

    public double getH() {
        return h;
    }

    public void setH(double h) {
        this.h = h;
    }

    Trapezoid(double a, double b, double h) {
        this.a = a;
        this.b = b;
        this.h = h;
    }

    Trapezoid() {
        a = 0;
        b = 0;
        h = 0;
    }

    @Override
    public double getArea() {
        // TODO Auto-generated method stub
        return (a + b) * h / 2;
    }

}

7.Cone.java

package Thirtenth;
/*
 * Cone类用来执行换底操作
 * getV方法来计算体积
 * 
 */
public class Cone {
    Shape shape;
    double high;

    public Shape getShape() {
        return shape;
    }

    public void setShape(Shape shape) {
        this.shape = shape;
    }

    public double getHigh() {
        return high;
    }

    public void setHigh(double high) {
        this.high = high;
    }

    Cone(Shape shape, double high) {
        this.shape = shape;
        this.high = high;
    }

    Cone() {
        shape = null;
        high = 0;
    }

    public double getV() {
        return shape.getArea() * high;
    }
}

8.Factory.java

package Thirtenth;
/*
 * 简单工厂模式
 * 根据输入的不同字符来对各种情况下的选择做输出
 * 
 */
import java.util.Scanner;

public class Factory {
    Shape shape = null;
    Scanner sc = new Scanner(System.in);
    Cone cone = new Cone();
    Shape getShape(char c) {
        switch (c) {
        case 'J':
            System.out.println("请输入以矩形为底的长：");
            double Ja = sc.nextDouble();
            System.out.println("请输入以矩形为底的宽：");
            double Jb = sc.nextDouble();
            shape = new Rectiangle(Ja, Jb);
            break;
        case 'Z':
            System.out.println("请输入以正方形为底的长:");
            double Za = sc.nextDouble();
            shape = new Square(Za);
            break;
        case 'S':
            System.out.println("请输入以三角形为底的边a:");
            double Sa = sc.nextDouble();
            System.out.println("请输入以三角形为底的边b:");
            double Sb = sc.nextDouble();
            System.out.println("请输入以三角形为底的边c:");
            double Sc = sc.nextDouble();
            shape = new Triangle(Sa, Sb, Sc);
            break;
        case 'Y':
            System.out.println("请输入以圆形为底的半径:");
            double Yr = sc.nextDouble();
            shape = new Circle(Yr);
            break;
        case 'T':
            System.out.println("请输入以梯形为底的上边a:");
            double Ta = sc.nextDouble();
            System.out.println("请输入以梯形为底的下边b:");
            double Tb = sc.nextDouble();
            System.out.println("请输入以梯形为底的高:");
            double Th = sc.nextDouble();
            shape = new Trapezoid(Ta, Tb, Th);
            break;
        }
        return shape;
    }
}

9.Test.java

package Thirtenth;
/*
 * 主方法创建对象并获取键盘录入值最后输出结果体积
 * 
 */
import java.util.Scanner;

public class Test {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc = new Scanner(System.in);
        Factory fac = new Factory();
        System.out.println("请输入要选择为底的图形模块：");
        System.out.println("1.正方形 2.矩形 3.三角形 4.圆形 5.梯形 (输入首字母即可)");
        while (true) {
            char c = sc.next().charAt(0);
            if (c != 'E') {
                System.out.println("请输入柱体的高度：");
                double h = sc.nextDouble();
                Cone cone = new Cone(fac.getShape(c), h);
                System.out.println(cone.getV());
            } else {
                System.out.println("退出循环选择，感谢使用。");
                return;
            }
        }
    }

}

三、运行结果