java 第九次作业

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

/* 5个形状类分别调用Shape接口；

柱体类中，定义求体积方法，换底求体积方法；

工厂类中，通过输入对应形状的字符，创建对应形状类型的对象。矩形用 j表示，圆形用c表示，正方形用z表示，三角形用s表示，梯形用t表示。**/

形状类

package ccut;

public interface Shape {
 double getArae();
}

5个形状

package ccut;
public class Zheng implements Shape {

    double bian;
     public Zheng(double bian){
            this.bian =bian;
        
        }
    public double getArae() {
        return bian*bian;
    }

}

package ccut;
import java.math.*;
public class Circle implements Shape {
double r;
public Circle(double r){
    this.r=r;
}
    public double getArae() {
        return Math.PI*r*r;
    }

}

package ccut;
import java.math.*;
public class SanJiaoXing implements Shape {

    double a,b,c;
    double p;
    public SanJiaoXing(double a,double b,double c){
        this.a=a;
        this.b=b;
        this.c=c;
    }
    public double getArae() {
        p=(a+b+c)/2;
        
        return Math.sqrt(p*(p-a)*(p-b)*(p-c));
    }

}

package ccut;

public class TiXing implements Shape {
double a,b,h;
public TiXing(double a,double b,double h){
    this.a=a;
    this.b=b;
    this.h=h;
}
    public double getArae() {
        
        return (a+b)*h/2;
    }

}

package ccut;

public class Rect implements Shape {
    double chang;
    double kuan;
    public Rect(double chang,double kuan){
        this.chang =chang;
        this.kuan =kuan;
    }
    public double getArae() {
         return chang*kuan;
    }

}

工厂类

package ccut;
import ccut.Shape;
public class Factory {
    Shape getShape(char c){
        Shape shape=null;
        switch(c){
        case 'j':shape=new Rect(3,4);break;
        case 'z':shape=new Zheng(5);break;
        case 'c':shape=new Circle(4);break;
        case 's':shape=new SanJiaoXing(5,5,6);break;
        case 't':shape=new TiXing (2,3,4);break;
        }
        return shape;
    }
    
}

柱体类

package ccut;
import ccut.Shape;
public class ZhuTi {
double height;
Shape shape;
 public ZhuTi(Shape shape,double height){
     this.height=height;
    this.shape=shape;
  
}
  void setShape(Shape shape){
     this.shape=shape;
 }
 public double getV(){
     return shape.getArae()*height;
 }
}

主类

package ccut;
import ccut.ZhuTi;
import ccut.Factory;
import java.util.*;
public class Test {
   public static void main(String[] args) {
    
  Scanner r =new Scanner(System.in);
  System.out.println("请输入底的类型：");
  char c=r.next().charAt(0);
  Factory factory=new Factory();
  factory.getShape(c);
  ZhuTi zhuti=new ZhuTi(factory.getShape(c),5);
System.out.println("体积为："+zhuti.getV());
  System.out.println("请输入新的底的类型：");
  c=r.next().charAt(0);
  zhuti.setShape(factory.getShape(c));
  System.out.println("体积为："+zhuti.getV());
    }

}

三、运行结果