简单工厂模式加减乘除器

 1 package com.main.cul;
 2 import java.util.Scanner;
 3 import com.factory.Operation;
 4 public class Demo {
 5     private static double result;
 6     public static void main(String[] argv){
 7     
 8     try{
 9         
10         Scanner in=new Scanner(System.in);
11         System.out.print("请输入数字A：");
12         double numA=in.nextDouble();
13         
14         System.out.print("请选择操作+-*/(加减乘除)：");
15         String strOper=in.next();
16         char  operate=strOper.charAt(0);
17         
18         System.out.print("请输入数字B：");
19         double numB=in.nextDouble();
20         System.out.println("您输入的数字A："+numA);
21         System.out.println("您输入的操作："+operate);
22         System.out.println("您输入的数字B："+numB);
23         Operation oper=OperationFactory.createOperate(operate);
24         Demo.result=oper.getResult(numA,numB);
25         System.out.print("结果为"+result);
26         
27     }catch (Exception e) {
28         // TODO: handle exception
29         e.printStackTrace();
30     }
31     }
32 }

工厂类

 1 package com.main.cul;
 2 
 3 import com.factory.AddOper;
 4 import com.factory.DivOper;
 5 import com.factory.MulOper;
 6 import com.factory.Operation;
 7 import com.factory.SubOper;
 8 
 9 
10 
11 public abstract class  OperationFactory {
12 
13     public static Operation createOperate(char ope){
14         Operation oper =null;
15         switch (ope) {
16         case '+':
17             oper =new AddOper(); 
18             break;
19         case '-':
20             oper =new SubOper(); 
21             break;
22         case '*':
23             oper =new MulOper(); 
24             break;
25         case '/':
26             oper =new DivOper(); 
27             break;
28         }
29         return oper;}
30 }

加减乘除类：

1 package com.factory;
2 
3 public abstract class Operation {
4     protected double numA;
5     protected double numB;
6     protected double result;
7     public abstract double getResult(double numA, double numB);
8 }

 1 package com.factory;
 2 
 3 public class AddOper extends Operation {
 4 
 5     public double getResult(double numA,double numB){
 6         result=numA+numB;
 7         return result;
 8         
 9     }
10 }

package com.factory;
public class SubOper extends Operation {
    public double getResult(double numA,double numB){
        result=numA-numB;
        return result;
        
    }
}

1 package com.factory;
2 public class MulOper extends Operation {
3     public double getResult(double numA,double numB){
4         result=numA*numB;
5         return result;
6         
7     }
8 }

 1 package com.factory;
 2 public class DivOper extends Operation {
 3     public double getResult(double numA,double numB){
 4         if(numB==0){
 5             
 6             System.out.print("除数不能为0");
 7         }
 8         result=numA/numB;
 9         return result;
10         
11     }
12 }