nhibernate - 多线程应用程序中的Fluent Nhibernate配置错误

Question

我已经在IIS(ASP.NET MVC)上创建了一个多线程应用程序，当线程服务器启动时，它会创建10个线程，并且正在线程中执行工作项。

通常我的应用程序运行良好，但是有一段时间我遇到了错误，并且我确定该问题来自流畅的配置。而且我敢肯定，我犯了一些错误:)

这是我的SessionFactory类:

public class NHibernateHelper
{
    private static ISessionFactory sessionFactory;

    /// <summary>
    /// SessionFactory is static because it is expensive to create and is therefore at application scope.
    /// The property exists to provide 'instantiate on first use' behaviour.
    /// </summary>
    private static ISessionFactory SessionFactory
    {
        get
        {
            if (sessionFactory == null)
            {
                sessionFactory = CreateSessionFactory();
            }
            return sessionFactory;
        }
    }


    /// <summary>
    /// CreateSessionFactory
    /// </summary>
    /// <returns></returns>
    private static ISessionFactory CreateSessionFactory()
    {
        IPersistenceConfigurer dbConfigurer = MsSqlConfiguration.MsSql2005
            .ConnectionString("connection string ..")
                            .Cache(c => c
                                .UseQueryCache()
                                .ProviderClass<NoCacheProvider>()
                    ).ShowSql()
                    .CurrentSessionContext<ThreadStaticSessionContext>(); 
                    return Fluently
                            .Configure()
                            .Database(dbConfigurer)
                            .Mappings(mc =>
                            {
                                mc.FluentMappings.Add(typeof(UserMap));
                                mc.FluentMappings.Add(typeof(ApplicationMap));
                                mc.FluentMappings.Add(typeof(SubscriptionsMap));
                            })
                        .BuildSessionFactory();
    }


    public static ISession GetCurrentSession()
    {
        if (!CurrentSessionContext.HasBind(SessionFactory))
        {
            CurrentSessionContext.Bind(SessionFactory.OpenSession());
        }
        return SessionFactory.GetCurrentSession();
    }



    public static void DisposeSession()
    {
        var session = GetCurrentSession();
        session.Close();
        session.Dispose();
    }

    public static void BeginTransaction()
    {
        GetCurrentSession().BeginTransaction();
    }

    public static void CommitTransaction()
    {
        var session = GetCurrentSession();
        if (session.Transaction.IsActive)
            session.Transaction.Commit();
    }

    public static void RollbackTransaction()
    {
        var session = GetCurrentSession();
        if (session.Transaction.IsActive)
            session.Transaction.Rollback();
    }
}

每个线程都调用NHibernateHelper类，其中的这一行本身;

            var myobjectinstance = new ObjectInstance();
            NHibernateHelper.GetCurrentSession().Save( myobjectinstance );

我看到，当我启动服务器一段时间后，它已成功调用300.000个工作项以进行测试。但是有时它会给出大约2-3个工作项的错误。

异常(exception)是:

[0] = {"An invalid or incomplete configuration was used while creating a SessionFactory. Check PotentialReasons collection, and InnerException for more detail.\r\n\r\n"}

内在兴奋是:

Object reference not set to an instance of an object.

内部异常堆栈跟踪为:

    at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
    at System.Collections.Generic.Dictionary`2.set_Item(TKey key, TValue value)
    at NHibernate.Impl.SessionFactoryObjectFactory.AddInstance(String uid, String name, ISessionFactory instance, IDictionary`2 properties)
    at NHibernate.Impl.SessionFactoryImpl..ctor(Configuration cfg, IMapping mapping, Settings settings, EventListeners listeners)
    at NHibernate.Cfg.Configuration.BuildSessionFactory()
    at FluentNHibernate.Cfg.FluentConfiguration.BuildSessionFactory() 
    in d:\Builds\FluentNH\src\FluentNHibernate\Cfg\FluentConfiguration.cs:line 93

欢迎任何建议或帮助

Answer 1

好像CreateSessionFactory方法被多次调用了。在此方法中，sessionFactory静态字段访问未同步，这使它不是线程安全的:

private static ISessionFactory SessionFactory
{
    get
    {
        if (sessionFactory == null)
        {
            sessionFactory = CreateSessionFactory();
        }
        return sessionFactory;
    }
}

确保始终同步对多线程应用程序中共享资源的访问。在这种情况下，有一个常用的模式称为singleton。