“省事的活多半效率不高”，对编程来说，很多时候适用。NHibernate省却我们写Sql语句、存储过程，且数据库的移植又是相当方便，效率估计有一些影响。
那影响有多大呢？
为此我利用一个现有的WebService，试图去比较使用NHibernate和直接使用SqlClient之间的性能差异。
private ISessionFactory _sessions;
public void Configure()
{
Configuration cfg = new Configuration();
cfg.SetProperty("hibernate.connection.provider","NHibernate.Connection.DriverConnectionProvider");
cfg.SetProperty("hibernate.dialect","NHibernate.Dialect.MsSql2000Dialect");
cfg.SetProperty("hibernate.connection.driver_class","NHibernate.Driver.SqlClientDriver");
cfg.SetProperty("hibernate.connection.connection_string","Server=localhost;initial catalog=Supercargo;user id=sa;password=network");
cfg.AddClass(typeof(Supercargo.Batch));
cfg.AddClass(typeof(Supercargo.Product));
cfg.AddClass(typeof(Supercargo.BatchItem));
this._sessions = cfg.BuildSessionFactory();
}
每一次的都从头到尾执行一次
this.Configure();
ISession session = _sessions.OpenSession();
ITransaction transaction = session.BeginTransaction();
session.Save(product1);
transaction.Commit();
session.Close();
SqlClient也一样从头到尾
SqlConnection connect = new SqlConnection("Server=localhost;initial");
try
{
connect.Open();
SqlCommand cmd = new SqlCommand(sql,connect);
cmd.ExecuteNonQuery();
}
catch(Exception ee)
{
str= string.Format("语句：{0} \r\n错误：{1}",sql, ee.Message);
}
connect.Close();
执行100次的以上操作，NHibernate用了近6秒，直接使用SqlClient却用了不到2秒。NHibernate真的如此不济？
稍作思考，将NHibernate的过程分解了一下。首先使用一个类包装一下Configure
/**//// <summary>
/// DbConfigure 的摘要说明。
/// </summary> public class DbConfigure
{
/**//// <summary>
/// 获取 Web应用程序的当前配置
/// </summary>
public static DbConfigure CurrentConnect
{
get
{
DbConfigure con = null;
object obj = System.Web.HttpContext.Current.Application["Connect"];
if(obj == null)
{
con = new DbConfigure();
System.Web.HttpContext.Current.Application["Connect"] = con;
}
else
con = (DbConfigure)obj;
return con;
}
}
/**//// <summary>
/// 构造函数
/// </summary>
public DbConfigure()
{
this.configure();
}
/**//// <summary>
/// 打开连接。
/// </summary>
/// <returns></returns>
public ConnectSession OpenSession()
{
return new ConnectSession(this._sessions.OpenSession());
}
private ISessionFactory _sessions;
private void configure()
{
Configuration cfg = new Configuration();
cfg.SetProperty("hibernate.connection.provider","NHibernate.Connection.DriverConnectionProvider");
cfg.SetProperty("hibernate.dialect","NHibernate.Dialect.MsSql2000Dialect");
cfg.SetProperty("hibernate.connection.driver_class","NHibernate.Driver.SqlClientDriver");
cfg.SetProperty("hibernate.connection.connection_string","Server=localhost;initial catalog=Superca");
cfg.AddClass(typeof(SD.Supercargo.Batch));
cfg.AddClass(typeof(SD.Supercargo.Product));
cfg.AddClass(typeof(SD.Supercargo.BatchItem));
this._sessions = cfg.BuildSessionFactory();
}
}
也将ISession简单的封装到ConnectSession中
/**//// <summary>
/// ConnectSession 的摘要说明。
/// </summary> public class ConnectSession
{
public ConnectSession(ISession pSession)
{
this.mDbSession = pSession;
}
public void Close()
{
this.mDbSession.Close();
}
public void BeginTransaction()
{
this.mTransaction = this.mDbSession.BeginTransaction();
}
public void CommitTransaction()
{
this.mTransaction.Commit();
}
public void Update(object obj)
{
this.DbSession.Update(obj);
}
public void Save(object obj)
{
this.DbSession.Save(obj);
}
public void SaveOrUpdate(object obj)
{
this.DbSession.SaveOrUpdate(obj);
}
private ITransaction mTransaction;
/**//// <summary>
/// 设置、获取Transaction
/// </summary>
public ITransaction Transaction
{
get
{
if(this.mTransaction == null)
this.mTransaction = this.mDbSession.BeginTransaction();
return this.mTransaction;
}
}
private ISession mDbSession;
/**//// <summary>
/// 获取DbSession
/// </summary>
public ISession DbSession
{
get{return this.mDbSession;}
set{this.mDbSession = value;}
}
} 测试过程只执行以下几步
DbConfigure con = DbConfigure.CurrentConnect;
ConnectSession connect = con.OpenSession();
ProductLocator prdLoc = new ProductLocator(connect.DbSession);
Product prd = new Product();
//一些赋值操作
connect.BeginTransaction();
prdLoc.Update(prd);
connect.CommitTransaction();
connect.Close();
NHibernate的成绩一下子提高到只需1.3秒多些，只稍慢于SqlClient的1.2秒，同样是操作100次。代码上的差异主要是用Application保存DbConfigure，Web应用程序只主要在启动的时候执行DbConfigure的Configure方法
public static DbConfigure CurrentConnect
{
get
{
DbConfigure con = null;
object obj = System.Web.HttpContext.Current.Application["Connect"];
if(obj == null)
{
con = new DbConfigure();
System.Web.HttpContext.Current.Application["Connect"] = con;
}
else
con = (DbConfigure)obj;
return con;
}
}
当然对于windows应用程序就可以省下这个心了。看来NHibernate的是相当值得使用!