NHibernate Session Management(One per request)

最近在学习NHibernate,发现有2种方式 实现

1.SessionManager.cs

public sealed class SessionManager
    {
        private const string CurrentSessionKey = "nhibernate.current_session";
        private static readonly ISessionFactory sessionFactory;
        public static Configuration CurrentConfig { get; set; }
        static SessionManager()
        {
            if (sessionFactory == null)
            {
                var cfg = new ATMSConfiguration();
                var model = AutoMap.AssemblyOf<Users>(cfg);
                CurrentConfig = Fluently.Configure()
                    .Database(MsSqlConfiguration
                                  .MsSql2005
                                  .ConnectionString(c => c.FromConnectionStringWithKey("DbString"))
                    )
                    .Mappings(m => m.AutoMappings.Add(model))
                    .BuildConfiguration();
                sessionFactory = CurrentConfig.BuildSessionFactory();
            }
        }

        public static ISession GetCurrentSession()
        {
            HttpContext context = HttpContext.Current;
            ISession currentSession = context.Items[CurrentSessionKey] as ISession;

            if (currentSession == null)
            {
                currentSession = sessionFactory.OpenSession();
                context.Items[CurrentSessionKey] = currentSession;
            }
            return currentSession;
        }

        public static void CloseSession()
        {
            HttpContext context = HttpContext.Current;
            ISession currentSession = context.Items[CurrentSessionKey] as ISession;

            if (currentSession == null)
            {
                // No current session
                return;
            }
            currentSession.Close();
            context.Items.Remove(CurrentSessionKey);
        }

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

2.SessionModule.cs

public class SessionModule : IHttpModule
    {
        private ISession _session;
        public void Init(HttpApplication context)
        {
            context.BeginRequest += new EventHandler(BeginTransaction);
            context.EndRequest += new EventHandler(CloseSession);
        }
        private void CloseSession(object sender, EventArgs e)
        {
            SessionManager.CloseSession();
        }
        //Create our session
        private void BeginTransaction(object sender, EventArgs e)
        {
            _session = SessionManager.GetCurrentSession();
        }
        public void Dispose()
        {
            _session = null;
        }
    }

Repository.cs

public class NHibernateRepository<T> : IRepository<T> where T : class
    {
        protected ISession session = SessionManager.GetCurrentSession();
        public T Get(object id)
        {

            using (var transaction = session.BeginTransaction())
            {
                T returnVal = session.Get<T>(id);
                transaction.Commit();
                return returnVal;
            }
        }
        public void Save(T value)
        {
            using (var transaction = session.BeginTransaction())
            {
                session.Save(value);
                transaction.Commit();
            }
        }
        public void Update(T value)
        {
            using (var transaction = session.BeginTransaction())
            {
                session.Update(value);
                transaction.Commit();
            }
        }
        public void Delete(T value)
        {
            using (var transaction = session.BeginTransaction())
            {
                session.Delete(value);
                transaction.Commit();
            }
        }
        public IList<T> GetAll()
        {
            using (var transaction = session.BeginTransaction())
            {
                IList<T> returnVal = session.CreateCriteria<T>().List<T>();
                transaction.Commit();
                return returnVal;
            }
        }
        /// <summary>
        /// Generate DataBaseSchemal
        /// </summary>
        /// <param name="AreYouSure"></param>
        public void GenerateSchema(DBCheck AreYouSure)
        {
            if (AreYouSure == DBCheck.ThisWillDropMyDatabase)
                new SchemaExport(SessionManager.CurrentConfig).Execute(true, true, false);
        }
    }

这种HTTPModule方法，会为每个HttpRequest(例如js,img加载) 都会opensession/close session.

另外一种方式是采用DI（依赖注入）的方式Ninject

SessionInjectHelper.cs

public  class SessionInjectHelper  {
        public static string SESSION_KEY = "NHibernate.ISession";    
        public static  NHibernate.ISession GetRequestSession(IContext Ctx)
        {
            IDictionary Dict = HttpContext.Current.Items;
            NHibernate.ISession Session;
            if (!Dict.Contains(SESSION_KEY))
            {
                // Create an NHibernate session for this request
                Session = (Ctx.Kernel.GetService(typeof(SharedConfiguration)) as SharedConfiguration).OpenSession();
                Dict.Add(SESSION_KEY, Session);
            }
            else
            {
                // Re-use the NHibernate session for this request
                Session = (NHibernate.ISession)Dict[SESSION_KEY];
            }
            return Session;
        }
    }

 Inject Service

 private static void RegisterServices(IKernel kernel)
        {
            kernel.Bind<IUsersRepository>().To<UserRepository>();
            var cfg = new SharedConfiguration();
            kernel.Bind<SharedConfiguration>().ToConstant(cfg);
            kernel.Bind<NHibernate.ISession>().ToMethod(x => SessionInjectHelper.GetRequestSession(x));
        }

 最后在Application_End

 public class MvcApplication : System.Web.HttpApplication
    {
        public MvcApplication()
        {
            this.EndRequest += MvcApplication_EndRequest;
        }
        private void MvcApplication_EndRequest(object sender, System.EventArgs e)
        {
            if (Context.Items.Contains(SessionInjectHelper.SESSION_KEY))
            {
                NHibernate.ISession Session = (NHibernate.ISession)Context.Items[SessionInjectHelper.SESSION_KEY];
                Session.Close();
                Session.Dispose();
                Context.Items[SessionInjectHelper.SESSION_KEY] = null;
            }
        }