Question

我开始使用nHibernate，并希望从第一天开始就这样做，所以这就是我使用ISession的方式。（根据要求提供网站）

这是我的帮手：

using System;
using System.Data;
using System.Web;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Cfg.MappingSchema;
using NHibernate.Context;
using NHibernate.Dialect;
using NHibernate.Driver;
using NHibernate.Mapping.ByCode;
using NHibernate.Tool.hbm2ddl;

namespace Gigastence.nHibernate.Web
{
    public static class Helper
    {
        #region Public Enums

        public enum DatabaseType
        {
            MSSQL2005,
            MSSQL2008,
            MySQL,
            MySQL5
        }

        #endregion

        #region Private Members

        private static HbmMapping _hbmMapping;
        private static Type[] _mappingTypes;
        private static Configuration _nHibernateConfiguration;

        #endregion

        #region Public Properties

        public static bool GenerateStatistics { get; set; }
        public static string ConnectionString { get; set; }

        public static ISession GetCurrentSession
        {
            get
            {
                //  Store the current ISession
                ISession tempSession = GetSessionFactory.GetCurrentSession();

                //  Return the current Session in for the relevant Context
                return tempSession.IsOpen ? tempSession : OpenSession();
            }
        }

        public static ISessionFactory GetSessionFactory { get; private set; }
        public static DatabaseType WorkingDatabaseType { get; set; }

        #endregion

        #region Private Methods

        private static void CompileSessionFactory()
        {
            //  ToDo: See if we can speed up this process by creating a static file to reference
            //
            //  Build the nHibernate Configuration and store it
            _nHibernateConfiguration = ConfigureNHibernate();

            //  Deserialize and Add the supplied Mappings to the nHibernate Configuration
            _nHibernateConfiguration.AddDeserializedMapping(_hbmMapping, null);

            //  ToDo: Figure out what this does!
            //
            SchemaMetadataUpdater.QuoteTableAndColumns(_nHibernateConfiguration);

            //  Create the Session Factory and store it
            GetSessionFactory = _nHibernateConfiguration.BuildSessionFactory();
        }

        private static Configuration ConfigureNHibernate()
        {
            //  Create a new nHibernate configuration
            var configure = new Configuration();

            //      ToDo: Allow for setting name of SessionFactory
            //
            //  Name the Session Factory
            configure.SessionFactoryName("Default");

            //  Wire up Session Factory Database component based on working database type
            switch (WorkingDatabaseType)
            {
                case DatabaseType.MySQL5:

                    //  !!! Is a MySQL 5 Database
                    configure.DataBaseIntegration(db =>
                    {
                        db.Dialect<MySQL5Dialect>();
                        db.Driver<MySqlDataDriver>();
                        db.KeywordsAutoImport = Hbm2DDLKeyWords.AutoQuote;
                        db.IsolationLevel = IsolationLevel.ReadCommitted;
                        db.ConnectionString = ConnectionString;
                        db.Timeout = 10;
                    });
                    break;
            }

            //  Generate Statistics, if required
            if (GenerateStatistics) configure.SessionFactory().GenerateStatistics();

            //  ToDo: Add modifier based on required Session Context
            //
            configure.CurrentSessionContext<ManagedWebSessionContext>();

            //  Return the Configuration
            return configure;
        }

        #endregion

        #region Public Methods

        public static void AddMapping(Type mappingType)
        {
            //  Determine if array is already available
            if (_mappingTypes == null)
            {
                //  Create a new array with one element
                _mappingTypes = new Type[1];
            }

            //  Copy existing array into a new array with one more element
            Array.Resize(ref _mappingTypes, _mappingTypes.Length + 1);

            //  Add the Mapping Type
            Array.Copy(new object[] { mappingType }, 0, _mappingTypes, _mappingTypes.Length - 1, 1);
        }

        public static void AddMappings(Type[] mappingTypes)
        {
            //  Iterate through passed types
            foreach(Type passedType in mappingTypes)
            {
                //  Add each typre
                AddMapping(passedType);
            }
        }

        public static void Application_BeginRequest()
        {
            //  Add the ISession object to the current request's Context for use throughout the request
            ManagedWebSessionContext.Bind(HttpContext.Current, OpenSession());
        }

        public static void Application_End()
        {
            //  Dispose of the Session Factory
            GetSessionFactory.Dispose();
        }

        public static void Application_EndRequest()
        {
            //  Unbind the Session from the request's context and place in the ISession holder
            ISession session = ManagedWebSessionContext.Unbind(HttpContext.Current, GetSessionFactory);

            //  Flush and Close the Session if it is still open
            if (session == null || !session.IsOpen) return;

            //  Proceed
            session.Flush();
            session.Close();
            session.Dispose();
        }

        public static void Application_Error()
        {
            //  Rollback transaction if there is one
            RollbackTransaction();
        }

        public static void BuildDatabase()
        {
            //  ToDo: Tidy Up and extend
            new SchemaExport(_nHibernateConfiguration).Execute(false, true, false);
        }

        public static void BuildSessionFactory(bool forceRebuild)
        {
            //  Determine if this is a forced rebuild
            if (forceRebuild)
            {
                //  !!! Forced rebuild

                //  Compile Session Factory
                CompileSessionFactory();
            }
            else
            {
                //  !!! Not a forced rebuild

                //  Reference the current Session Factory if available
                ISessionFactory sessionFactory = GetSessionFactory;

                //  Determine if Session Factory is built already
                if (sessionFactory == null)
                {
                    //  Compile Session Factory
                    CompileSessionFactory();
                }
            }
        }

        public static void CompileMappings(Type baseEntityToIgnore)
        {
            //  Using the built-in auto-mapper
            var mapper = new ModelMapper();

            //  Add prefetched Types to Mapper
            mapper.AddMappings(_mappingTypes);

            //  Compile the retrieved Types into the required Mapping
            _hbmMapping = mapper.CompileMappingForAllExplicitlyAddedEntities();
        }

        public static ISession OpenSession()
        {
            return GetSessionFactory.OpenSession();
        }

        public static void RollbackTransaction()
        {
            //  Get the current ISession from the request's context and place in the ISession holder
            ISession session = GetCurrentSession;

            //  Determine if the ISession exists
            if (session == null) return;

            //  It does, rollback current transaction if there is one
            if (session.Transaction.IsActive && !session.Transaction.WasRolledBack)
            {
                //  There was a transaction, rollback
                session.Transaction.Rollback();
            }
        }

        #endregion
    }
}

这就是我使用它的方式：

using (ISession session = Helper.GetCurrentSession)
{
    using (ITransaction transaction = session.BeginTransaction())
    {
        //  Add data to the NHibernateSchemaVersions table
        var table = new NHibernateSchemaVersions { Component = "Web.Provider.Membership", Version = 1 };
        session.Save(table);

        transaction.Commit();
    }
}

到目前为止，我得到的就是我应该做的事情，将工作包装在交易中。

我发现，由于ISession对象上的USING语句，会话在每次调用结束时关闭;这就是我添加逻辑以检查Helper.GetCurrentSession调用是否仍然打开的原因。

我这样做了吗？我认为会话是为了保持活着直到请求结束，它确定它何时进入数据库。

我应该简单地提取会话并使用它而不是USING语句：

ISession session = Helper.GetCurrentSession;

using (ITransaction transaction = session.BeginTransaction())
{
    //  Add data to the NHibernateSchemaVersions table
    var table = new NHibernateSchemaVersions { Component = "Web.Provider.Membership", Version = 1 };
    session.Save(table);

    transaction.Commit();
}

如果是这种情况，我会在其他地方遇到问题吗？

感谢您的时间和帮助。

注意：我确实找到了答案，但我无法将我的问题与任何事情联系起来。如果我错过了，请指点链接。

Answer 1

我遇到了同样的问题。我现在在请求结束时明确Dispose()会话 - 解决了问题。

由于我的库也用于非Web应用程序，我的帮助程序类和我的存储库提供了两个入口点 - 一个用于“持久”会话（显式关闭），另一个用于每个行程会话（隐式关闭using陈述）。

“持久”会话的另一个非常好的用途是，如果您在关系映射上使用延迟加载。如果在检索“父”对象时（通过using语句）自动关闭会话，然后尝试检索延迟加载属性，则会生成异常，因为会话将会尝试使用已关闭。

<强>更新

根据要求，这是我目前的帮助班 - 我的是非常基本的。我的所有配置都在XML文件中。对于我的MVC Web应用程序，我通过调用NHibernateHelper.GetPersistentSession().Dispose()在EndRequest的监听器中关闭Global.asx中的会话。

public class NHibernateHelper
{
    private static ISessionFactory _sessionFactory;
    private static ISessionFactory SessionFactory
    {
        get
        {
            if (_sessionFactory == null)
            {
                var configuration = new NHibernate.Cfg.Configuration();
                configuration.Configure();
                configuration.AddAssembly(typeof(NHibernateHelper).Assembly);
                _sessionFactory = configuration.BuildSessionFactory();
            }
            return _sessionFactory;
        }
    }

    public static ISession OpenSession()
    {
        return SessionFactory.OpenSession();
    }

    private static ISession _persistentSession = null;
    public static ISession GetPersistentSession()
    {
        if (_persistentSession == null)
        {
            _persistentSession = SessionFactory.OpenSession();
        }

        return _persistentSession;
    }
}

我在这里正确使用nHibernate的ISession吗？

1 个答案: