1 /** 2  * 面向对象（运算类） 3  * 简易计算器 4  * @author Monica 5  * 6  */ 7 public class Operation { 8     private double numberA = 0; 9     private double numberB = 0;10     11     //虚函数12     public double GetResult() {13         double result = 0;14         return result;15     }16 17     public double getNumberA() {18         return numberA;19     }20 21     public void setNumberA(double numberA) {22         this.numberA = numberA;23     }24 25     public double getNumberB() {26         return numberB;27     }28 29     public void setNumberB(double numberB) {30         this.numberB = numberB;31     }32 }

 1 /** 2  * 加法 3  * @author Monica 4  * 5  */ 6 public class OperationAdd extends Operation { 7      8     /** 9      * 继承运算类10      */11     @Override12     public double GetResult() {13         double result = 0;14         result = getNumberA() + getNumberB();15         return super.GetResult();16     }17 }

 1 /** 2  * 简单工厂模式 3  * @author Administrator 4  * 5  */ 6 public class OperationFactory { 7  8     public static Operation createOperate(char operate) { 9         Operation oper = null;10         switch (operate) {11         case ‘+‘:12             oper = new OperationAdd();13             break;14         }15         return oper;16     }17 }

 1 public class Main { 2  3     /** 4      * @param args 5      */ 6     public static void main(String[] args) { 7         Operation oper;  8         oper = OperationFactory.createOperate(‘+‘); 9         oper.setNumberA(1);10         oper.setNumberB(2);11         double result = oper.GetResult();12     }13 14 }