1． 学习目的
学习Nhibernate基础知识。掌握Nhibernate的配置方法，实现对单表的简单操作，如:创建表，查询，添加，删除，修改。
2． 开发环境+前期准备
开发环境: windows 2003,Visual studio .Net 2005,Sql server 2005 developer edition
前期准备: Nhibernate框架,我用的目前最新版NHibernate-1.2.0.CR1, 下载地址:        http://downloads.sourceforge.net/nhibernate/NHibernate-1.2.0.CR1.msi?modtime=1172161735&big_mirror=0
3． 开发步骤:
1).双击下载下来的NHibernate-1.2.0.CR1.msi,将其安装到某个目录，我的目录为: E:\download project\orm\nhibernate.,打开该目录，即可以看到bin,doc,src三个子目录，分别为Realse好的dll或者exe目录，文档说明目录，和源程序目录.
2).打开visual studio 2005,创建类库项目NhibernateSample1
3).在解决方案管理其中，右键点击引用-添加引用，在选项卡种选择浏览，设定查找范围为：E:\download project\orm\nhibernate\bin,添加对Nhibernate.dll,log4net.dll, Iesi.Collections, HashCodeProvider四个dll的引用.
4).打开SQL Server Management Studio,创建数据库nhibernate。
5).在解决方案管理器中添加hibernate.cfg.xml文件。将下面代码粘贴到此文件: 

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-configuration  xmlns="urn:nhibernate-configuration-2.2" >
    <session-factory name="NHibernate.Test">
        <!-- properties -->
        <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
        <property name="connection.driver_class">NHibernate.Driver.SqlClientDriver</property>
        <property name="connection.connection_string">Server=127.0.0.1;initial catalog=nhibernate;uid=sa;pwd=123;</property>
        <property name="show_sql">false</property>
        <property name="dialect">NHibernate.Dialect.MsSql2005Dialect</property>
        <property name="use_outer_join">true</property>
        <!-- mapping files -->
        <mapping assembly="NhibernateSample1" />
    </session-factory>    
</hibernate-configuration>

 该文件是Nhibernate的配置文件，其中connection.connection_string为数据库连接字符串，Dialect项因为我用的是SQL2005,所以为:MsSql2005Dialect注意:<mapping assembly=”NhibernateSample1”/>表示映射NhibernateSample1程序集下的所有类，所以以后不要需要Configuration.AddClass(..)了；

6).添加类文件:User.cs,添加代码: 

using System;
using System.Collections.Generic;
using System.Text;

namespace NhibernateSample1
{
    public class User
    {
        private int _id;
        private string _name;
        private string _pwd;
        /**//// <summary>
        /// 编号
        /// </summary>
        public virtual int Id
        {
            get
            {
                return _id;
            }
            set
            {
                _id = value;
            }
        }

        /**//// <summary>
        /// 名称
        /// </summary>
        public virtual string Name
        {
            get
            {
                return _name;
            }
            set
            {
                _name = value;
            }
        }

        /**//// <summary>
        /// 密码
        /// </summary>
        public virtual string Pwd
        {
            get
            {
                return _pwd;
            }
            set
            {
                _pwd = value;
            }
        }
    }
}

 6).编写User类的映射配置文件:User.hbm.xml

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
  <class name="NhibernateSample1.User,NhibernateSample1" table="Users" lazy="false">
    <id name="Id" column="Id" unsaved-value="0">
      <generator class="native" />
    </id>
    <property name="Name" column="Name" type="string" length="64" not-null="true" unique="true"></property>
    <property name="Pwd"  column="Pwd"  type="string" length="64" not-null="true"></property>
  </class>
</hibernate-mapping>

  注意:该映射文件的属性中的生成操作必须为：嵌入的资源.

7).编写管理ISession对象的辅助类: NHibernateHelper.cs,代码为:

using System;
using System.Web;
using NHibernate;
using NHibernate.Cfg;

namespace NhibernateSample1
{
    public sealed class NHibernateHelper
    {
        private static readonly ISessionFactory sessionFactory;

        static NHibernateHelper()
        {
            sessionFactory = new Configuration().Configure(@"E:\my project\nhibernate study\simle 1\NHibernateStudy1\NhibernateSample1\hibernate.cfg.xml").BuildSessionFactory();
        }

        public static ISession GetCurrentSession()
        {             
            ISession currentSession = sessionFactory.OpenSession();
            return currentSession;
        }

        public static void CloseSessionFactory()
        {
            if (sessionFactory != null)
            {
                sessionFactory.Close();
            }
        }
    }
}

注:因为我用的是单元测试，所以这里的配置文件路径写成固定的了。如果换成windows或者Web程序，可以直接去掉该路径。

8) 编写测试CRUD类:UserFixue

using System;
using System.Collections.Generic;
using System.Text;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Tool.hbm2ddl;
namespace NhibernateSample1
{
    public class UserFixure
    {
        private ISession session;
        public UserFixure()
        {
            
        }
        /**//// <summary>
        /// 创建表
        /// </summary>
        public bool ExportTable()
        {
            try
            {
                Configuration cfg = new Configuration().Configure(@"E:\my project\nhibernate study\simle 1\NHibernateStudy1\NhibernateSample1\hibernate.cfg.xml");
                session = NHibernateHelper.GetCurrentSession();
                ITransaction transaction = session.BeginTransaction();
                new SchemaExport(cfg).Create(true, true);
                transaction.Commit();
                return true;
            }
            catch(Exception ex)
            {
                throw ex; 
            }
            finally
            {
                session.Close();
            }
        }
        /**//// <summary>
        /// 添加
        /// </summary>
        public int Add()
        {
            try
            {
                User u = new User();
                u.Name = Guid.NewGuid().ToString();
                u.Pwd = "124";
                session = NHibernateHelper.GetCurrentSession();
                ITransaction transaction = session.BeginTransaction();
                session.Save(u);
                transaction.Commit();
                return u.Id;
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                session.Close();
            }
        }
        /**//// <summary>
        /// 更新
        /// </summary>
        /// <param name="uid"></param>
        public bool Update(int uid)
        {
            try
            {
                session = NHibernateHelper.GetCurrentSession();
                ITransaction transaction = session.BeginTransaction();
                User u = session.Load(typeof(User), uid) as User;
                if (u != null)
                {
                    u.Name = "updatedName";
                    session.SaveOrUpdate(u);
                    transaction.Commit();
                    u = session.Load(typeof(User), uid) as User;
                    if (u.Name == "updatedName")
                    {
                        return true;
                    }
                }
                return false;
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                session.Close();
            }
        }
        /**//// <summary>
        /// 删除
        /// </summary>
        /// <param name="uid"></param>
        /// <returns></returns>
        public bool Delete(int uid)
        {
            try
            {
                session = NHibernateHelper.GetCurrentSession();
                ITransaction transaction = session.BeginTransaction();
                User u = session.Get(typeof(User), uid) as User;
                if (u != null)
                {
                   session.Delete(u);
                   transaction.Commit();
                   u = session.Get(typeof(User), uid) as User;
                   if (u == null)
                   {
                       return true;
                   }
                }
                return false;
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                session.Close();
            }
        }
        public System.Collections.IList Query()
        {
            try
            {
                session = NHibernateHelper.GetCurrentSession();
                ITransaction transaction = session.BeginTransaction();
                System.Collections.IList list= session.CreateQuery("select u from User as u").List();
                transaction.Commit();
                return list;
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                session.Close();
            }
        }
    }
}

9)创建新单元测试项目: TestProject1,添加NhibernateSample1的引用
10）创建单元测试类: UnitTest1.cs,并输入如下代码:

using System;
using System.Text;
using System.Collections.Generic;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using NhibernateSample1;

namespace TestProject1
{
    /**//// <summary>
    /// UnitTest1 的摘要说明
    /// </summary>
    [TestClass]
    public class UnitTest1
    {
        public UnitTest1()
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }

        其他测试属性#region 其他测试属性
        //
        // 您可以在编写测试时使用下列其他属性:
        //
        // 在运行类中的第一个测试之前使用 ClassInitialize 运行代码
        // [ClassInitialize()]
        // public static void MyClassInitialize(TestContext testContext) { }
        //
        // 在类中的所有测试都已运行之后使用 ClassCleanup 运行代码
        // [ClassCleanup()]
        // public static void MyClassCleanup() { }
        //
        // 在运行每个测试之前使用 TestInitialize 运行代码 
        // [TestInitialize()]
        // public void MyTestInitialize() { }
        //
        // 在运行每个测试之后使用 TestCleanup 运行代码
        // [TestCleanup()]
        // public void MyTestCleanup() { }
        //
        #endregion

        int uid;
        [TestMethod]
        public void TestMethod1()
        {
            UserFixure userFixure = new UserFixure();
            Assert.IsTrue(userFixure.ExportTable());            
        }
        [TestMethod]
        public void TestMethod2()
        {
            UserFixure userFixure = new UserFixure();
            uid = userFixure.Add();
            Assert.IsTrue(uid>0);
        }
        [TestMethod]
        public void TestMethod3()
        {
            UserFixure userFixure = new UserFixure();
            Assert.IsTrue(userFixure.Update(uid));
        }
        [TestMethod]
        public void TestMethod4()
        {
            UserFixure userFixure = new UserFixure();
            Assert.IsTrue(userFixure.Delete(uid));
        }
        [TestMethod]
        public void TestMethod5()
        {
            UserFixure userFixure = new UserFixure();
            Assert.IsTrue(userFixure.Query().Count>0);
        }
    }
}

11）在菜单-测试-加载元数据文件 选择NHibernateStudy1.vsmdi，然后按顺序执行TestMethod1-TestMethod5,全部成功!
4.总结
 通过使用Nhibernate，基本上可以使开发人员不在接触繁琐的数据库表和数据库操作代码，您唯一需要关心的就是如何设计好类，让这些类满足您的业务需求。从扩展性来说Nhinernate具有非常好的扩展性。与代码生成比较，Nhibernate更改数据表结构对代码的影响要远远小于代码生成。
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