第一个 NHibernate 程序

NHibernate程序的配置一直是一个很让人郁闷的问题.今天下午实验NHibernate程序，终于实现了写入数据库的操作。现在在此记录

过程中遇见了很多问题。都会一一阐述。

 

 

1.下载NHibernate 3.1.0GA bin.

2.建立一个普通的控制台程序，加入必须的dll和动态加载的dll，以castle为例。Castle.Core.dll，NHibernate.ByteCode.Castle.dll

3.建立数据库表，数据库名字叫TEST，表名为person

        

4.编写entity类

  

5.编写这个类对应的配置文件。注意要将其build action属性设置为embedded resourse

<?xml version="1.0" encoding="utf-8" ?><hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHTestOne" namespace="NHTestOne"><class name="person"><id name="id" column="id"></id><property name="value"/></class></hibernate-mapping>

6.编写hibernate.cfg.xml,注意将其copy to output directory属性设置为copy always.

<?xml version="1.0" encoding="utf-8"?><hibernate-configuration xmlns="urn:nhibernate-configuration-2.2" ><session-factory><property name="connection.driver_class">NHibernate.Driver.SqlClientDriver</property><property name="connection.connection_string">Server=./SQLEXPRESS;initial catalog=TEST;uid=sa;pwd=password;Integrated Security=SSPI</property><property name="adonet.batch_size">10</property><property name="show_sql">false</property><property name="dialect">NHibernate.Dialect.MsSql2005Dialect</property><property name="use_outer_join">true</property><property name="command_timeout">60</property><property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property><property name="proxyfactory.factory_class">NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle</property><mapping assembly="NHTestOne"/></session-factory></hibernate-configuration>

7.编写helper类，放在NHHelper.cs中

using System;using System.Collections.Generic;using System.Linq;using System.Text;using NHibernate.Cfg;using NHibernate;namespace NHTestOne{ public class NHHelper { private ISessionFactory _sessionFactory; public NHHelper() { _sessionFactory = GetSessionFactory(); } private ISessionFactory GetSessionFactory() { return (new Configuration()).Configure().BuildSessionFactory(); } public ISession GetSession() { return _sessionFactory.OpenSession(); } } public class NHibernateSample { protected ISession Session { get; set; } public NHibernateSample(ISession session) { Session = session; } public void CreatePerson(person person) { Session.Save(person); Session.Flush(); } public person GetPersonById(int id) { return Session.Get<person>(id); } }}

8.编写主函数

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace NHTestOne{ class Program { static void Main(string[] args) { NHibernateSample sample = new NHibernateSample(new NHHelper().GetSession()); person p = new person() { id = 1, value = "xt" }; sample.CreatePerson(p); } }}

 

 

项目目录：

 

在做的过程中发现了如下错误：

1.    NHibernate.MappingException: No persister for .....的错误，这个错误是发生在hibernate.cfg.xml上面，我按照下载的NHibernate的Configuration_Templates中的配置的拷贝过来，发现是不对的。这个错误的配置是如下的：

<?xml version="1.0" encoding="utf-8"?><hibernate-configuration xmlns="urn:nhibernate-configuration-2.2" > <session-factory name="NHibernate.Test"> <property name="connection.driver_class">NHibernate.Driver.SqlClientDriver</property> <property name="connection.connection_string"> Server=./SQLEXPRESS;initial catalog=TEST;uid=sa;pwd=password;Integrated Security=SSPI </property> <property name="adonet.batch_size">10</property> <property name="show_sql">false</property> <property name="dialect">NHibernate.Dialect.MsSql2005Dialect</property> <property name="use_outer_join">true</property> <property name="command_timeout">60</property> <property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property> <property name="proxyfactory.factory_class">NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle</property> </session-factory></hibernate-configuration>

要把session-factory中的name属性去掉，然后在session-factory中加入一个<mapping assembly="xxx"/>的子元素。

2.发生 “Cannot insert the value NULL into column ...”的错误，发生这个错误的原因是因为当时我照抄别人的配置，而这个人的配置是这么写的（如下），在person.hbm.xml中.这里我的数据库中的表中id不是自动生成的，因此这里不需要这个generator，去掉即可。

<id name="id" column="id"> <generator class="native"/> </id>

 

PS:hibernate.cfg.xml中可以简写为

<?xml version="1.0" encoding="utf-8"?><hibernate-configuration xmlns="urn:nhibernate-configuration-2.2" > <session-factory> <!--<property name="connection.provider">NHibernate.Connection.DriverConnectionProvider,NHibernate</property>--> <!--<property name="connection.driver_class">NHibernate.Driver.SqlClientDriver</property>--> <property name="connection.connection_string"> Server=./SQLEXPRESS;initial catalog=TEST;uid=sa;pwd=password;Integrated Security=SSPI </property> <property name="dialect">NHibernate.Dialect.MsSql2005Dialect</property> <property name="proxyfactory.factory_class">NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle</property> <mapping assembly="NHTest1"/> <!-- <property name="adonet.batch_size">10</property> <property name="show_sql">false</property> <property name="use_outer_join">true</property> <property name="command_timeout">60</property> <property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property> --> </session-factory></hibernate-configuration>

mapping元素主要指定到哪里去找hbm.xml文件

这种方式的配置也可以指定hibernate.cfg.xml文件的名字，例如，改为cookbook.cfg.xml,这样加载配置文件的方式得改为

var cfgFile = "cookbook.cfg.xml";var nhConfig = new Configuration().Configure(cfgFile);

此外，还有在app.config里面，code配置方式，fluent nhibernate配置方式，ConfORM方式。具体可以参见《Packtpub.NHibernate.3.0.Cookbook.Oct.2010》第二章。