Factory Pattern简单随笔

约定不等于承诺〃 2022-04-01 14:27 172阅读 0赞

工厂方法模式解决了许多简单工厂模式的问题。首先完全实现‘开－闭 原则’，实现了可扩展。其次更复杂的层次结构，可以应用于产品结果复杂的场合。

工厂方法模式的对简单工厂模式进行了抽象。有一个抽象的Factory类（可以是抽象类和接口），这个类将不在负责具体的产品生产，而是只制定一些规范，具体的生产工作由其子类去完成。在这个模式中，工厂类和产品类往往可以依次对应。即一个抽象工厂对应一个抽象产品，一个具体工厂对应一个具体产品，这个具体的工厂就负责生产对应的产品。

在软件系统中，经常面临着“某个对象”的创建工作，由于需求的变化，这个对象的具体实现经常面临着剧烈的变化，但是它却拥有比较稳定的接口。

提供一种封装机制来隔离出“这个易变对象”的变化，从而保持系统中“其它依赖该对象的对象”不随着需求的改变而改变

visio图解为：

![factoryvisio.jpg][]

类关系图为：

![factory.jpg][]

首先构建工厂类：

1 using  System;  
  2  using  System.Collections.Generic;  
  3  using  System.Linq;  
  4  using  System.Text;  
  5   
  6  namespace  FactoryPatternSam  
  7 \{  
  8  public  abstract  class  Factory  
  9  \{  
 10  public  abstract  Product CreateInstance();  
 11  \}  
 12 \}  
 13   
 14   
 15   
 16  using  System;  
 17  using  System.Collections.Generic;  
 18  using  System.Linq;  
 19  using  System.Text;  
 20   
 21  namespace  FactoryPatternSam  
 22 \{  
 23  public  class  FactoryEntityOne:Factory  
 24  \{  
 25  public  override  Product CreateInstance()  
 26  \{  
 27  // throw new NotImplementedException();   
 28   return  new  ProductEntityOne();  
 29  \}  
 30  \}  
 31 \}  
 32   
 33  using  System;  
 34  using  System.Collections.Generic;  
 35  using  System.Linq;  
 36  using  System.Text;  
 37   
 38  namespace  FactoryPatternSam  
 39 \{  
 40  public  class  FactoryEntityTwo:Factory  
 41  \{  
 42  public  override  Product CreateInstance()  
 43  \{  
 44  // throw new NotImplementedException();   
 45   return  new  ProductEntityTwo();  
 46  \}  
 47  \}  
 48 \}  
 49   
 50  using  System;  
 51  using  System.Collections.Generic;  
 52  using  System.Linq;  
 53  using  System.Text;  
 54   
 55  namespace  FactoryPatternSam  
 56 \{  
 57  public  class  FactoryEntityThree : Factory  
 58  \{  
 59  public  override  Product CreateInstance()  
 60  \{  
 61  // throw new NotImplementedException();   
 62   return  new  ProductEntityThree();  
 63  \}  
 64  \}  
 65 \}

建造产品类：

1 using  System;  
  2  using  System.Collections.Generic;  
  3  using  System.Linq;  
  4  using  System.Text;  
  5   
  6  namespace  FactoryPatternSam  
  7 \{  
  8  public  abstract  class  Product  
  9  \{  
 10  public  abstract  void  CreateProduct();  
 11  \}  
 12 \}  
 13   
 14  using  System;  
 15  using  System.Collections.Generic;  
 16  using  System.Linq;  
 17  using  System.Text;  
 18   
 19  namespace  FactoryPatternSam  
 20 \{  
 21  public  class  ProductEntityOne:Product  
 22  \{  
 23  public  override  void  CreateProduct()  
 24  \{  
 25  //  throw new NotImplementedException();   
 26   Console.WriteLine( " \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* " );  
 27  Console.WriteLine( " Create Product one!!! " );  
 28  Console.WriteLine( " \--------------------- " );  
 29  \}  
 30  \}  
 31 \}  
 32   
 33  using  System;  
 34  using  System.Collections.Generic;  
 35  using  System.Linq;  
 36  using  System.Text;  
 37   
 38  namespace  FactoryPatternSam  
 39 \{  
 40  public  class  ProductEntityThree : Product  
 41  \{  
 42  public  override  void  CreateProduct()  
 43  \{  
 44  // throw new NotImplementedException();   
 45   Console.WriteLine( " \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* " );  
 46  Console.WriteLine( " Create Product THREE!!! " );  
 47  Console.WriteLine( " \--------------------- " );  
 48  \}  
 49  \}  
 50 \}  
 51   
 52  using  System;  
 53  using  System.Collections.Generic;  
 54  using  System.Linq;  
 55  using  System.Text;  
 56   
 57  namespace  FactoryPatternSam  
 58 \{  
 59  public  class  ProductEntityTwo:Product  
 60  \{  
 61  public  override  void  CreateProduct()  
 62  \{  
 63  // throw new NotImplementedException();   
 64   Console.WriteLine( " \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* " );  
 65  Console.WriteLine( " Create Product Two!!! " );  
 66  Console.WriteLine( " \--------------------- " );  
 67  \}  
 68  \}  
 69 \}  
 70

构建常量和其他操作类： 获取相应的产品类--->

1 using  System;  
  2  using  System.Collections.Generic;  
  3  using  System.Linq;  
  4  using  System.Text;  
  5   
  6  namespace  FactoryPatternSam  
  7 \{  
  8  public  static  class  ConfigureInstance  
  9  \{  
 10  private  static  string  configStr  =  ConfigureSet.ConfigureSetString;  
 11  private  static  Factory \_Factory = (Factory)System.Reflection.Assembly.Load( " FactoryPatternSam " ).CreateInstance( " FactoryPatternSam. "  \+  configStr);  
 12   
 13  public  static  Factory Instance  
 14  \{  
 15  get   
 16  \{  
 17  return  \_Factory;  
 18  \}  
 19  \}  
 20  \}  
 21 \}  
 22   
 23   
 24  using  System;  
 25  using  System.Collections.Generic;  
 26  using  System.Linq;  
 27  using  System.Text;  
 28  using  System.Configuration;  
 29   
 30  namespace  FactoryPatternSam  
 31 \{  
 32  public  static  class  ConfigureSet  
 33  \{  
 34  private  static  string  \_ConfigureSetString  =  System.Configuration.ConfigurationManager.ConnectionStrings\[ " ProductType " \].ToString();  
 35   
 36  public  static  string  ConfigureSetString  
 37  \{  
 38  get  \{  
 39  return  \_ConfigureSetString;  
 40  \}  
 41  \}  
 42  \}  
 43 \}  
 44

配置文件类 ：设置相应的类型：

1 <? xml version = " 1.0 "  encoding = " utf-8 "  ?>   
 2  < configuration >   
 3  < connectionStrings >   
 4  < add name = " ProductType "  connectionString = " FactoryEntityOne " />   
 5  </ connectionStrings >   
 6  </ configuration >

客户端代码如下：

1 using  System;  
  2  using  System.Collections.Generic;  
  3  using  System.Linq;  
  4  using  System.Text;  
  5   
  6  namespace  FactoryPatternSam  
  7 \{  
  8  class  Program  
  9  \{  
 10  static  void  Main( string \[\] args)  
 11  \{  
 12  Factory factory  =  ConfigureInstance.Instance;  
 13   
 14  Product pro  =  factory.CreateInstance();  
 15  pro.CreateProduct();  
 16  Console.ReadLine();  
 17  \}  
 18  \}  
 19 \}  
 20

\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*

工厂模式源代码下载：[/Files/jasenkin/FactoryPatternSam.rar][Files_jasenkin_FactoryPatternSam.rar]

[factoryvisio.jpg]: /images/20220401/1f5dc24633b44294822cb4ee7aef1d43.png
[factory.jpg]: /images/20220401/e08631a5f6ad46b0beefba07eeeb95e9.png
[Files_jasenkin_FactoryPatternSam.rar]: http://files.cnblogs.com/jasenkin/FactoryPatternSam.rar