Spring.Net+NHibenate+Asp.Net mvc +ExtJs 系列 3 ----数据访问层

   在上一篇中,我们已经搭建起了整个解决方案的项目,并且建好了数据库,完成了实体类和Nhibernate映射文件.在本文中,将定义数据访问接口,并利用Nhibernate实现接口,利用Spring.net配置起来dao.并对其进行单元测试.

   数据访问层也和Petshop等框架一样,分为数据访问的接口以及实现,不过这里的数据访问实现相比之下就清晰和明显了的多,Nhibernate本身就是支持多数据库的,所以这样做不是为了多数据库,而是为了Nhibernate的可插拨,即使哪一天发现由于一些问题,比如说性能问题,可以重新实现IDAL接口,而不会对业务层造成比较大的改动.

   说到这里,其实我们还不太清楚前台到底需要哪些功能,所以我们就先简单的实现实体的增删改查吧.等需要其它的功能时,再来完善接口和实现.

   DirectCenter.IDAL不依赖于Spring或者是Nhibernate,只需要添加项目引用DirectCenter.Model.以用户来说吧,添加接口IUserDao.cs

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->using System.Collections;using DirectCenter.Model;namespace DirectCenter.IDAL{    public interface IUserDao    {        User FindById(string userId);        void Delete(User user);        User Save(User user);        User SaveOrUpdate(User user);    }}

 

   同样,我们添加ICompanyDao和IDepartmentDao.

   接下来,我们实现刚才的数据接口,DirectCenter.DAL项目中添加对DirectCenter.IDAL和DirectCenter.Model的项目引用,然后再添加引用Spring.Data.NHibernate20,Spring.Data,Spring.Core(在lib/Spring.net下面).

     一种方式是可以直接使用Nhibernate完成数据访问:

       

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->   public User Save(User user)        {          //通过一种方式获取Session           Session session = SessionFactory.OpenSession();           session.Save(user);       }

 

     不过我们不打算使用这种单纯Nhibernate的方式,而是使用继承spring对hibernate的封装类HibernateDaoSupport,这样我们把Spring.net作为Nhibernate的容器可以方便的进行统一管理和利用一些特性.

    

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->using System.Collections;using Spring.Data.NHibernate.Support;using DirectCenter.IDAL;using DirectCenter.Model;namespace DirectCenter.DAL{   public  class UserDao:HibernateDaoSupport,IUserDao    {       public User Save(User user)        {           HibernateTemplate.Save(user);           return user;       }       public User SaveOrUpdate(User user)       {           HibernateTemplate.SaveOrUpdate(user);           return user;       }       public void Delete(User user)        {           HibernateTemplate.Delete(user);       }       public User  FindById(string userId)        {          return  HibernateTemplate.Get(typeof(User), userId) as User;       }    }}

 

   同时添加CompanyDao和DepartmentDao.

    一个HibernateTemplate怎么就完成了上面的这些操作.Nhibernate相关的呢?Session在哪里?通过查看代码,我们知道HibernateTemplate是HibernateDaoSupport的一个属性,我们就截取HibernateTemplate的一些代码片断来简单看一下:

   

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->        /// <summary>        /// Gets or sets the session factory that should be used to create        /// NHibernate ISessions.        /// </summary>        /// <value>The session factory.</value>        public override ISessionFactory SessionFactory        {            get { return sessionFactory; }            set            {                sessionFactory = value;            }        }             /// <summary>        /// Gets or sets the template flush mode.        /// </summary>        /// <remarks>        /// Default is Auto. Will get applied to any <b>new</b> ISession        /// created by the template.        /// </remarks>        /// <value>The template flush mode.</value>        public override TemplateFlushMode TemplateFlushMode        {            get { return templateFlushMode; }            set { templateFlushMode = value; }        }     /// <summary>        /// Gets or sets a value indicating whether to         /// cache all queries executed by this template.        /// </summary>        /// <remarks>        /// If this is true, all IQuery and ICriteria objects created by        /// this template will be marked as cacheable (including all        /// queries through find methods).        /// <p>To specify the query region to be used for queries cached        /// by this template, set the QueryCacheRegion property.        /// </p>        /// </remarks>        /// <value><c>true</c> if cache queries; otherwise, <c>false</c>.</value>        public override bool CacheQueries        {            get { return cacheQueries; }            set { cacheQueries = value; }        }     public object Load(Type entityType, object id, LockMode lockMode)        {            return Execute(new LoadByTypeHibernateCallback(entityType, id, lockMode),true);                }  internal class LoadByTypeHibernateCallback : IHibernateCallback    {        private Type entityType;        private object id;        private LockMode lockMode;        public LoadByTypeHibernateCallback(Type entityType, object id, LockMode lockMode)        {            this.entityType = entityType;            this.id = id;            this.lockMode = lockMode;        }        /// <summary>        /// Gets called by HibernateTemplate with an active        /// Hibernate Session. Does not need to care about activating or closing        /// the Session, or handling transactions.        /// </summary>        /// <remarks>        /// <p>        /// Allows for returning a result object created within the callback, i.e.        /// a domain object or a collection of domain objects. Note that there's        /// special support for single step actions: see HibernateTemplate.find etc.        /// </p>        /// </remarks>        public object DoInHibernate(ISession session)        {            if (lockMode != null)             {                return session.Load(entityType, id, lockMode);            }            else             {                return session.Load(entityType, id);            }        }    }

    本质还是通过调用Nhibernate的Session来完成的,具体的原来请查看相关资料或源代码.

    但是只有上面的代码肯定是不行的,我们在哪里连接数据库呢?通过IOC向HibernateTemplate中注入SessionFactory,然后在Spring.net中声明一个SessionFactory的对象.

    DirectCenter.App添加一个Dao.xml,主要是是进行数据访问的配置.

     

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--><?xml version="1.0" encoding="utf-8" ?><objects xmlns="http://www.springframework.net"         xmlns:db="http://www.springframework.net/database">                        <!-- 用以我们在其它的应用程序中，配置数据访问 -->    <object type="Spring.Objects.Factory.Config.PropertyPlaceholderConfigurer, Spring.Core">        <property name="ConfigSections" value="databaseSettings"/>    </object>    <!-- 数据库和Nhibernate的相关配置 -->    <db:provider id="DbProvider"                     provider="SqlServer-2.0"                     connectionString="Data Source=miaozy;Database=DirectCenter;Integrated Security=true;User Instance=false;"/>                         <!--SessionFactory对象，其中包括一些比较重要的属性 -->                  <object id="NHibernateSessionFactory" type="Spring.Data.NHibernate.LocalSessionFactoryObject, Spring.Data.NHibernate20">        <property name="DbProvider" ref="DbProvider"/>        <property name="MappingAssemblies">            <list>                <value>DirectCenter.Model</value>            </list>        </property>        <property name="HibernateProperties">            <dictionary>                <entry key="hibernate.connection.provider"                       value="NHibernate.Connection.DriverConnectionProvider"/>                <entry key="dialect"                       value="NHibernate.Dialect.MsSql2000Dialect"/>                <entry key="hibernate.connection.driver_class"                       value="NHibernate.Driver.SqlClientDriver"/>            </dictionary>        </property>        <property name="ExposeTransactionAwareSessionFactory" value="true" />    </object>    <!--将id为NHibernateSessionFactory的对象注入到HibernateTemplate中-->    <object id="HibernateTemplate" type="Spring.Data.NHibernate.HibernateTemplate">        <property name="SessionFactory" ref="NHibernateSessionFactory" />        <property name="TemplateFlushMode" value="Auto" />        <property name="CacheQueries" value="true" />    </object>    <!-- 我们的数据访问类，将HibernateTemplate注入进来-->    <object id="UserDao" type="DirectCenter.DAL.UserDao, DirectCenter.DAL">        <property name="HibernateTemplate" ref="HibernateTemplate"/>    </object>    <object id="CompanyDao" type="DirectCenter.DAL.CompanyDao, DirectCenter.DAL">        <property name="HibernateTemplate" ref="HibernateTemplate"/>    </object>    <object id="DepartmentDao" type="DirectCenter.DAL.DepartmentDao, DirectCenter.DAL">        <property name="HibernateTemplate" ref="HibernateTemplate"/>    </object>   </objects>

 

    注意: 1.NHibernateSessionFactory的MappingAssemblies属性,是我们实体映射文件所在的程序集,也可以通过MappingResources属性引入映射文件,通过ConfigFilenames属性引入Nhibernate的配置文件hibernate.cfg.xml

            2.这里的HibernateProperties属性是指定的是dialect,而不是hibernate.dialect.这是Nhibernate 2.0更新的.不然会提示"Could not find the dialect in the configuration"

 

接下来,就让测试一下我们的代码吧.稍微检验一下我们的成果.为DirectCenter.UnitTest项目添加相关的引用,其中重要的是NUnit.Framework和Spring.Testing.NUnit.
添加测试类,UserDaoTest.cs

 

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->using System;using NUnit.Framework;using Spring.Testing.NUnit;using DirectCenter.Model;using DirectCenter.IDAL;namespace DirectCenter.UnitTest{    [TestFixture]    public class UserDaoTest : AbstractTransactionalDbProviderSpringContextTests    {        protected override string[] ConfigLocations        {            get            {                return new String[] { "objects.xml" };            }        }        protected IUserDao UserDao        {            get            {                return applicationContext.GetObject("UserDao") as IUserDao;            }        }        [Test]        public void SaveUserTest()        {            User user = new User();            user.UserID = "buyer000";            user.Password = "1356";            user.UserName = "刘翔";            user.ValidFrom = Convert.ToDateTime("2008-8-18");            user.ValidTo = Convert.ToDateTime("2012-8-18");            user.CreateTime = DateTime.Now;            UserDao.Save(user);        }    }}

 

objectx.xml中引入我们的配置文件dao.xml ,另外应用程序配置文件App.Config中有Spring.Net和Nhibernate的相关配置信息,就不贴太多代码了.呵呵

利用nunit运行SaveUserTest,发现显示测试成功了,不过查看数据库为什么没有添加进去呢??? ?

淡定淡定,因为我们并没有提交,在最后加上   transactionManager.Commit(transactionStatus);再看一下结果..剩余的我还都并没有测试,如果你尝试,就尝试其它的dao的方法吧...

 

回过头来,看我们的Dao的实现,基本上都是那几种,而且继承于HibernateDaoSupport ,这样使我们的数据访问直接依赖于Spring.net和Nhibernate,以后想直接拿掉Spring.net或者是更换版本都会有些困难,怎么办呢.可以写一个基类继承于HibernateDaoSupport ,并且通过泛型或者是获以当前类型统一完成这些操作.这个我看下,可以放在最后再来讲一下我的实现.

 

 ps.希望这篇文章能够给也在使用类似框架的朋友带来些收获,这样也不会违背放在首页的原则.目的还是想以这个框架的整合为主,以及我在使用的过程中遇到的一些问题和大家分享.至于Spring.Net或者是Nhibernate,Asp.net mvc相关的技术,请参考相关的学习资料.或者是在这里给我留言.

 

 本次代码下载

作者：孤独侠客（似水流年）
出处：http://lonely7345.cnblogs.com
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