Operation.java
package calc;
public abstract class Operation {
private static double _numberA = 0;
private static double _numberB = 0;
static class NumberA {
public static double get_numberA() {
return _numberA;
}
public static void set_numberA(double numberA) {
_numberA = numberA;
}
}
static class NumberB {
public static double get_numberB() {
return _numberB;
}
public static void set_numberB(double numberB) {
_numberB = numberB;
}
}
public abstract double GetResult();
}
class OperationAdd extends Operation {
public double GetResult() {
double result = 0;
result = NumberA.get_numberA() + NumberB.get_numberB();
return result;
}
}
class OperationSub extends Operation {
public double GetResult() {
double result = 0;
result = NumberA.get_numberA() - NumberB.get_numberB();
return result;
}
}
class OperationMul extends Operation {
public double GetResult() {
double result = 0;
result = NumberA.get_numberA() * NumberB.get_numberB();
return result;
}
}
class OperationDiv extends Operation {
@Override
public double GetResult() {
double result = 0;
if(NumberB.get_numberB() == 0)
try {
throw new Exception("not divide by zero");
} catch (Exception e) {
// TODO Auto-generated catch block
System.out.println("not divide by zero");
}
result = NumberA.get_numberA() / NumberB.get_numberB();
return result;
}
}
OperationFactory.java
package calc;
public class OperationFactory {
public static Operation createOperate (String operator) {
Operation oper = null;
if(operator == "+")
oper = new OperationAdd();
else if(operator == "-")
oper = new OperationSub();
else if(operator == "*")
oper = new OperationMul();
else if(operator == "/")
oper = new OperationDiv();
return oper;
}
}
测试类
package calc;
import java.io.*;
class Calculator { // 输入两个数， 相除得结果
/**
* @param args
*/
public static void main(String[] args) throws IOException {
// BufferedReader b = new BufferedReader(new InputStreamReader(System.in));
// System.out.println("please input a number A:");
// String A = b.readLine();
// System.out.println("please input a number B:");
// String B = b.readLine();
// int C = (new Integer(A)).intValue()/(new Integer(B)).intValue();
// System.out.println("The result is :" + C);
Operation oper;
oper = OperationFactory.createOperate("/");
Operation.NumberA.set_numberA(1);
Operation.NumberB.set_numberB(0);
double result = oper.GetResult();
System.out.println(result);
}
}