代码实现：
抽象一个运算类：
[java]
package com.qianyan.calcuator;
public abstract class Operation {
//数字一
private double num1;
//数字二
private double num2;
public double getNum1() {
return num1;
}
public void setNum1(double num1) {
this.num1 = num1;
}
public double getNum2() {
return num2;
}
public void setNum2(double num2) {
this.num2 = num2;
}
public abstract double getResult();
}
创建工厂类：
[java]
package com.qianyan.factory;
import com.qianyan.calcuator.AddOperation;
import com.qianyan.calcuator.Operation;
import com.qianyan.calcuator.SubtractOperation;
public class OperationFactory {
public static Operation getOperation(String oper){
if("+".equals(oper))
return new AddOperation();
else if("-".equals(oper))
return new SubtractOperation();
else
return null;
}
}
抽象运算的实现类：
[java]
package com.qianyan.calcuator;
public class AddOperation extends Operation{
@Override
public double getResult() {
return this.getNum1() + this.getNum2();
}
}
[java]
package com.qianyan.calcuator;
public class SubtractOperation extends Operation{
@Override
public double getResult() {
return this.getNum1() - this.getNum2();
}
}
用户类：
[java]
package com.qianyan.user;
import java.util.Scanner;
import com.qianyan.calcuator.Operation;
import com.qianyan.factory.OperationFactory;
public class User {
public static void main(String[] args) {
System.out.println("----小C计算器程序----");
Scanner input = new Scanner(System.in);
System.out.println("请输入第一个运算数字：");
String str1 = input.nextLine();
System.out.println("请输入运算符：");
String oper = input.nextLine();
System.out.println("请输入第二个运算数字：");
String str2 = input.nextLine();
double num1 = Double.parseDouble(str1);
double num2 = Double.parseDouble(str2);
Operation opertion = OperationFactory.getOperation(oper);
opertion.setNum1(num1);
opertion.setNum2(num2);
double result = opertion.getResult();
System.out.println(str1 + oper + str2 + "=" + result);
}
}
测试结果：
[java]
----小C计算器程序----
请输入第一个运算数字：
5
请输入运算符：
-
请输入第二个运算数字：
3
5-3=2.0
