Spring.NET依赖注入 制作可替换的算法

1. 配置文件

<configuration>
  <configSections>
    <sectionGroup name="spring">
      <section name="context" type="Spring.Context.Support.ContextHandler, Spring.Core"/>
      <section name="objects" type="Spring.Context.Support.DefaultSectionHandler, Spring.Core" />
    </sectionGroup>
  </configSections>

  <spring>
    <context>
      <resource uri="config://spring/objects"/>
    </context>
    
    <objects>
      <!-- Default Implement -->
      <object name="algHello" type="CsharpTrainer.Strategy.Hello.EngHello, CsharpTrainer.Strategy">
      </object>
      <!-- Extended Implement -->
      <!--<object name="algHello" type="CsharpTrainer.Strategy.Hello.ChnHello, CsharpTrainer.Strategy">
      </object>-->
    </objects>
  </spring>

  ...
</configuration>

2. 算法接口

  策略接口

public interface IStrategy
    {
        void Execute();
    }

算法1

public class EngHello : IStrategy
    {
        public void Execute()
        {
            Console.WriteLine("Hello, World!");
        }
    }

算法2

public class ChnHello : IStrategy
    {
        public void Execute()
        {
            Console.WriteLine("你好, 世界!");
        }
    }

3. Spring调用端

public class HelloAlgorithm
    {
        public static void SayHello()
        {
            //从config文件中取得程序集信息
            IApplicationContext context = ConfigurationManager.GetSection("spring/context") as IApplicationContext;

            //调用方法
            IStrategy alg = context.GetObject("algHello") as IStrategy;
            alg.Execute();
        }

4. 运行和替换

  运行程序,结果是Hello, World

  如果我们把算法配置换成

<object name="algHello" type="CsharpTrainer.Strategy.Hello.ChnHello, CsharpTrainer.Strategy">
</object>

  结果将是: 你好, 世界