Ado.Net连接池的速度测试

 using System;
 using System.Configuration;
 using System.Data.SqlClient;
 using System.Diagnostics;
 namespace ConsoleApplication1
 {
   class Program
   {
       static void Main(string[] args)
       {
           string _connString = ConfigurationManager.ConnectionStrings["ConnStr"].ToString();
           SqlConnection conn = new SqlConnection(_connString);
            Stopwatch sw = new Stopwatch();
            sw.Start();
           conn.Open();
           sw.Stop();
           Console.WriteLine("1连接所用时间：{0}" , sw.ElapsedTicks.ToString());
           conn.Close();//关闭连接
            sw.Reset();
           sw.Start();
           conn.Open();//现在是直接从连接池中分配的连接，所以速度要快很多
           sw.Stop();
           Console.WriteLine("2连接所用时间：{0}", sw.ElapsedTicks.ToString());
           conn.Dispose();//释放连接
           conn.ConnectionString = _connString;
            sw.Reset();
           sw.Start();
           conn.Open();//Dispose()后，仍然可以连接！(前提是必须重设连接字符串)
           sw.Stop();
           Console.WriteLine("3连接所用时间：{0}", sw.ElapsedTicks.ToString());//从输出结果上看，这一次仍然要比首次连接快很多，貌似也是从连接池中取的
           conn.Close();

           using (SqlConnection conn2 = new SqlConnection(_connString))
           {
               try
               {
                   sw.Reset();
                   sw.Start();
                   conn2.Open();//即使创建一个完全不同的新Connection对象，只要连接字符串相同，仍然会从连接池内中分配已有连接,所以速度仍然很快
                   sw.Stop();
                   Console.WriteLine("4连接所用时间：{0}", sw.ElapsedTicks.ToString());
               }
               catch (Exception)
               {
                    throw;
               }
               finally {
                   conn2.Close();
               }
           }
          
         
           //连续多次调用Close()或Dispose()不会抛出异常，但连续多次调用Open()会抛出异常
           //conn.Close();
           //conn.Close();
            //conn.Dispose();
           //conn.Dispose();
           Console.Read();
           //即使不关闭连接，程序退出时，连接也被会自动销毁
       }
   }
}