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。
图形Shape接口：
package com.ccut.hou;
/**
* 创建形状Shape接口
* @author ASUS
*
*/
public interface Shape {
abstract double getArea();
}
圆形类Circle实现形状Shape接口
package com.ccut.hou;
/**
* 定义圆形类Circle实现形状Shape接口
* @author ASUS
*
*/
public class Circle implements Shape {
final double PAI=3.14;
double r;
Circle(double r){
this.r=r;
}
public double getArea() {
return PAI*r*r;
}
}
定义柱体类
package com.ccut.hou;
/**
* 定义柱体类
* @author ASUS
*
*/
public class Cylinder{
Shape shape;
double height;
Cylinder(Shape shape,double height){
this.shape=shape;
this.height=height;
}
void changeBase(Shape shape) {
this.shape=shape;
}
double getVolume(){
return shape.getArea()*height;
}
}
长方形类Rec实现形状Shape的接口
package com.ccut.hou;
/**
* 创建长方形类Rec实现形状Shape的接口
* @author ASUS
*
*/
public class Rec implements Shape {
double length;
double width;
Rec(double length,double width){
this.length=length;
this.width=width;
}
public double getArea(){
return length*width;
}
}
正方形Squ实现形状Shape接口
package com.ccut.hou;
/**
* 创建正方形Squ实现形状Shape接口
* @author ASUS
*
*/
public class Squ implements Shape {
double length;
double area;
Squ(double length) {
this.length = length;
}
public double getArea() {
return area = length * length;
}
}
梯形类Trap实现形状Shape接口
package com.ccut.hou;
/**
* 定义梯形类Trap实现形状Shape接口
* @author ASUS
*
*/
public class Trap implements Shape {
double upper_base;
double under_base;
double height;
Trap(double upper_base, double under_base, double height) {
this.upper_base = upper_base;
this.under_base = under_base;
this.height = height;
}
public double getArea() {
return (upper_base + under_base) * height / 2;
}
}
三角形类Tri实现形状Shape接口
package com.ccut.hou;
/**
* 定义三角形类Tri实现形状Shape接口
* @author ASUS
*
*/
public class Tri implements Shape {
double a;
double b;
double c;
Tri(double a, double b, double c) {
this.a = a;
this.b = b;
this.c = c;
}
public double getArea() {
double d = (a + b + c) / 2;
return Math.sqrt(d * (d - a) * (d - b) * (d - c));
}
}
工厂类
package com.ccut.hou;
import java.util.Scanner;
/**
* 创建工厂类
* @author ASUS
*
*/
public class Factory {
Shape shape=null;
Scanner reader = new Scanner(System.in);
public Factory(double height) {
Cylinder podetium=new Cylinder(this.getShape(),height);
System.out.println(podetium.getVolume());
}
public Shape getShape() {
System.out.println("****请您按照以下提示操作****");
System.out.println("~键盘输入 1 即为求矩形的体积；");
System.out.println("~键盘输入 2 即为求正方形的体积；");
System.out.println("~键盘输入 3 即为求圆形的体积；");
System.out.println("~键盘输入 4 即为求三角形的体积；");
System.out.println("~键盘输入 5 即为求梯形的体积；");
char S=reader.next().charAt(0);
switch(S) {
case '1':System.out.println("矩形柱体的体积是：");shape=new Rec(3,4);break;
case '2':System.out.println("正方形柱体的体积是：");shape=new Squ(6);break;
case '3':System.out.println("圆形柱体的体积是：");shape=new Circle(6);break;
case '4':System.out.println("三角形柱体的体积是：");shape=new Tri(3,5,6);break;
case '5':System.out.println("梯形柱体的体积是：");shape=new Trap(3,5,6);break;
}
return shape;
}
}
主方法MAIN
package com.ccut.hou;
/**
* 创建主方法
* @author ASUS
*
*/
public class Main {
public static void main(String[] args) {
double height = 6;
Factory factory = new Factory(height);
}
}
运行截图
