Java学习笔记——设计模式之一简单工厂

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　　　　　　　　　　　　　　　　　——蜀道难

设计模式第一篇，简单工厂。

定义Operation类

 1 package cn.no1.simplefactory;
 2
 3 public abstract class Operation {
 4
 5     private double numA;
 6     private double numB;
 7
 8     public double getNumA() {
 9         return numA;
10     }
11
12
13     public void setNumA(double numA) {
14         this.numA = numA;
15     }
16
17
18     public double getNumB() {
19         return numB;
20     }
21
22
23     public void setNumB(double numB) {
24         this.numB = numB;
25     }
26
27     public abstract double calculate ();
28 }

定义其四个子类

 1 package cn.no1.simplefactory;
 2
 3 public class OperationAdd extends Operation{
 4
 5     @Override
 6     public double calculate() {
 7         // TODO Auto-generated method stub
 8         return this.getNumA() + this.getNumB();
 9     }
10
11 }
12 public class OperationSub extends Operation {
13
14     @Override
15     public double calculate() {
16         // TODO Auto-generated method stub
17         return this.getNumA()-this.getNumB();
18     }
19
20 }
21 public class OperationMultiply extends Operation{
22
23     @Override
24     public double calculate() {
25         // TODO Auto-generated method stub
26         return this.getNumA()*this.getNumB();
27     }
28
29 }
30 public class OperationDivide extends Operation{
31
32     @Override
33     public double calculate() {
34         // TODO Auto-generated method stub
35         return this.getNumA()/this.getNumB();
36     }
37
38 }

定义工厂类

 1 package cn.no1.simplefactory;
 2
 3 public class OperationFactory {
 4
 5     public static Operation createOperation(String operator){
 6         Operation operation = null;
 7         switch (operator) {
 8         case "+":
 9             operation = new OperationAdd();
10             break;
11         case "-":
12             operation = new OperationSub();
13             break;
14         case "*":
15             operation = new OperationMultiply();
16             break;
17         case "/":
18             operation = new OperationDivide();
19             break;
20 　　　　 }
21         return operation;
22     }
23 }

测试类:

 1 package cn.no1.simplefactory;
 2
 3 import java.util.Scanner;
 4
 5 public class _Test {
 6
 7     public static void main(String[] args) {
 8         Scanner sc = new Scanner(System.in);
 9         System.out.println("输入数字1:");
10         double numA = sc.nextDouble();
11         System.out.println("输入数字2:");
12         double numB = sc.nextDouble();
13         System.out.println("输入操作符:");
14         String operator = sc.next();
15         sc.close();
16         Operation operation = OperationFactory.createOperation(operator);
17         operation.setNumA(numA);
18         operation.setNumB(numB);
19         double result = operation.calculate();
20         System.out.println("计算结果是:"+result);
21     }
22 }