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

IUserDao.cs
<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />-->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:

UserDao.cs
<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />--> 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.

UserDao.cs
<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />-->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:

HibernateTemplate.cs
<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />--> /// <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.

Dao.xml
<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />--><?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

UserDaoTest.cs
<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />-->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