DDD~Unity在DDD中的使用

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上一讲介绍了DDD中的领域层，并提到下次要讲Unity，所以这篇文章当然就要介绍它了，呵呵，Unity是Microsoft.Practices中的一部分，主要实现了依赖注入的功能，或者叫它控制反转，对于控制反转(IoC)的文章我介绍了不少，Autofac,Castle等等，今天主要说一下Unity！

在我的ＤＤＤ架构项目中，各层间实现IoC使用的是Unity，因为考虑到AOP,cache等功能，所以就直接用Microsoft.Practices组件了，它真的很强大！这次的项目在业务上采用ＷＣＦ实现，所以ＷＣＦ业务与基础设施之间会有通信，而基础设施只是去实现Domain定义的功能，所以这两个层之间也会有通信，最后就是Domain与ＷＣＦ之间同样存在着接口的通信，如图：

aaarticlea/png;base64,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" alt="" />

Domain层定义一个接口，部分代码如下：

　　　　 /// <summary>
        /// 获取产品列表
        /// </summary>
        /// <returns></returns>
        IQueryable<Product> GetProduct();

基础设施层实现它

   　　  public IQueryable<Product> GetProduct()
        {
            return this.GetModel();
        }

它们之间的通信不存在IoC，因为如果你要使用其它的持久化方法，可以再建立一个项目，以别一种方式去实现持久化

WCF去声明一个Domain层的接口，实例化它的基础设施层的实例，这个过程需要解耦合，我们使用Unity来实现，它需要我们在config中去定义如何去实例化。

 public class ProductServiceImpl : IProductService
    {
        private readonly IProductRepository _productRepository;

        /// <summary>
        /// 构造方法注入
        /// </summary>
        /// <param name="productRepository"></param>
        public ProductServiceImpl(IProductRepository productRepository)
        {
            if (productRepository == (IProductRepository)null)
                throw new ArgumentException("context can't is null.");
            _productRepository = productRepository;
        }

        #region IProductService 成员
        public ProductDTO GetProductByID(int id)
        {
            Mapper.CreateMap<Product, ProductDTO>();
            return Mapper.Map<Product, ProductDTO>(_productRepository.Find(id));
        }
}

上面使用unity中的构造方法注入，我们还可以使用服务调度器进行注入，看这种代码

  　public class ProductService : ServiceBase, IProductService
    {

        //通过ServiceLocator从IoC容器中获得对象
        IProductService _productService = ServiceLocator.Instance.GetService<IProductService>();
        #region IProductService 成员

        public ProductDTO GetProductByID(int id)
        {
            return _productService.GetProductByID(id);
        }

    }

下面是配置文件中需要注入的代码片断，包括缓存模块和日志模块

<configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
    <section name="unity" type="Microsoft.Practices.Unity.Configuration.UnityConfigurationSection, Microsoft.Practices.Unity.Configuration" />
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
    <section name="cachingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Caching.Configuration.CacheManagerSettings, Microsoft.Practices.EnterpriseLibrary.Caching, Version=5.0.505.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
  </configSections>
<!--BEGIN: Unity-->
  <unity xmlns="http://schemas.microsoft.com/practices/2010/unity">
    <sectionExtension type="Microsoft.Practices.Unity.InterceptionExtension.Configuration.InterceptionConfigurationExtension, Microsoft.Practices.Unity.Interception.Configuration" />
    <container>
      <extension type="Interception" />
      <register type="Project.Caching.ICacheProvider,  Project.Caching" mapTo="Project.Caching.EntLibCacheProvider,  Project.Caching" />
      <!--对数据上下文的注入-->
      <register type="DDD_AOP_WCF.Domain.Products.IProductRepository, DDD_AOP_WCF.Domain" mapTo="DDD_AOP_WCF.Infrastructure.Repository.ProductRepository, DDD_AOP_WCF.Infrastructure" />
      <!--对WCF的访问进行的注入与缓存和异常的拦截-->
      <register type="DDD_AOP_WCF.ServiceContracts.IProductService, DDD_AOP_WCF.ServiceContracts" mapTo="DDD_AOP_WCF.Service.Implements.ProductServiceImpl, DDD_AOP_WCF.Service">
        <!--  <interceptor type="VirtualMethodInterceptor" />-->
        <interceptor type="InterfaceInterceptor" />
        <interceptionBehavior type="Project.InterceptionBehaviors.CachingBehavior, Project.InterceptionBehaviors" />
        <interceptionBehavior type="Project.InterceptionBehaviors.ExceptionLoggingBehavior, Project.InterceptionBehaviors" />
      </register>
    </container>
  </unity>
  <!--END: Unity-->
  <!--BEGIN: Caching-->
  <cachingConfiguration defaultCacheManager="ByteartRetailCacheManager">
    <cacheManagers>
      <add name="ByteartRetailCacheManager" type="Microsoft.Practices.EnterpriseLibrary.Caching.CacheManager, Microsoft.Practices.EnterpriseLibrary.Caching, Version=5.0.505.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" expirationPollFrequencyInSeconds="" maximumElementsInCacheBeforeScavenging="" numberToRemoveWhenScavenging="" backingStoreName="NullBackingStore" />
    </cacheManagers>
    <backingStores>
      <add type="Microsoft.Practices.EnterpriseLibrary.Caching.BackingStoreImplementations.NullBackingStore, Microsoft.Practices.EnterpriseLibrary.Caching, Version=5.0.505.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" name="NullBackingStore" />
    </backingStores>
  </cachingConfiguration>
  <!--END: Caching-->
 <!--BEGIN: log4net-->
  <log4net>
    <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
      <file value="log.log"/>
      <appendToFile value="true"/>
      <rollingStyle value="Size"/>
      <maxSizeRollBackups value="10"/>
      <maximumFileSize value="100KB"/>
      <staticLogFileName value="true"/>
      <layout type="log4net.Layout.PatternLayout">
        <param name="ConversionPattern" value="%newline%date [%thread] %-5level %logger - %message%newline"/>
      </layout>
    </appender>
    <logger name="ByteartRetail.Logger" >
      <!--control log level: ALL|DEBUG|INFO|WARN|ERROR|FATAL|OFF-->
      <!--如果没有定义LEVEL的值，则缺省为DEBUG-->
      <level value="INFO"/>
      <appender-ref ref="RollingFileAppender"/>
    </logger>
  </log4net>
  <!--END: log4net-->

好了，对于Unity在DDD中的使用就介绍到这里，如有不清楚的地方，可以直接给我留言或发email!

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