****************连接池代码***************************
/**
* 实现连接池
*
*/
using System;
using System.Collections;
using System.Timers;
namespace XuLongClass
{
/// <summary>
/// ObjectPool 的摘要说明。
/// </summary>
public abstract class ObjectPool
{
private long _lastCheckOut;
private static Hashtable locked;//正在使用的对象
private static Hashtable unlocked;//闲置的对象
internal static long GARBAGE_INTERVAL=90*1000;//90秒
static ObjectPool()
{
locked =Hashtable.Synchronized(new Hashtable());
unlocked=Hashtable.Synchronized(new Hashtable());
}
internal ObjectPool()
{
_lastCheckOut=DateTime.Now.Ticks;
Timer aTimer=new Timer();
aTimer.Enabled=true;
aTimer.Interval=GARBAGE_INTERVAL;
aTimer.Elapsed +=new ElapsedEventHandler(CollectGarbage);
}
//下面三个抽像方法需要继承类来实现
/// <summary>
/// 生成对象
/// </summary>
/// <returns></returns>
protected abstract object Create();
/// <summary>
/// 验证对象
/// </summary>
/// <param name="o"></param>
/// <returns></returns>
protected abstract bool Validate(object o);
/// <summary>
/// 销毁对象
/// </summary>
/// <param name="o"></param>
protected abstract void Expire(object o);
//获取对象
internal object GetObjectFromPool()
{
long now=DateTime.Now.Ticks;
_lastCheckOut=now;
object o=null;
lock(this)
{
try
{
//遍历闲置表
foreach(DictionaryEntry myEntry in unlocked)
{
o=myEntry.Key;
if(Validate(o))
{
unlocked.Remove(o);
locked.Add(o,now);
return(o);
}
else
{
unlocked.Remove(o);
Expire(o);
o=null;
}
}
}
catch(Exception)
{}
o=Create();
locked.Add(o,now);
}
return o;
}
/// <summary>
/// 将对象返回到池中。
/// </summary>
/// <param name="o"></param>
internal void ReturnObjectToPool(object o)
{
if(o!=null)
{
lock(this)
{
locked.Remove(o);
unlocked.Add(o,DateTime.Now.Ticks);
}
}
}
/// <summary>
/// 销毁无用对象
/// </summary>
/// <param name="sender"></param>
/// <param name="ea"></param>
private void CollectGarbage(object sender,System.Timers.ElapsedEventArgs ea)
{
lock(this)
{
object o;
long now=DateTime.Now.Ticks;
IDictionaryEnumerator e=unlocked.GetEnumerator();
try
{
while(e.MoveNext())
{
o=e.Key;
if((now-((long)unlocked[o])>GARBAGE_INTERVAL))
{
unlocked.Remove(o);
Expire(o);
o=null;
}
}
}
catch(Exception){}
}
}
}
}
***************************实现数据库连接池***************************
/**
* 通过继承对象池实现数据库对象池
*
*/
using System;
using System.Data.SqlClient;
namespace XuLongClass
{
/// <summary>
/// DBObjectPool 的摘要说明。
/// </summary>
public class DBObjectPool:ObjectPool
{
public DBObjectPool()
{
}
public static readonly DBObjectPool Instance=new DBObjectPool();
public static string _connectionString=new DataBase().MyConnectionString;
/// <summary>
/// 数据库连接字符串
/// </summary>
public static string ConnectionString
{
set
{
_connectionString=value;
}
get
{
return _connectionString;
}
}
/// <summary>
/// 创建对象
/// </summary>
/// <returns></returns>
protected override object Create()
{
SqlConnection temp=new SqlConnection(_connectionString);
temp.Open();
return (temp);
}
/// <summary>
/// 验证对象的有效性
/// </summary>
/// <param name="o"></param>
/// <returns></returns>
protected override bool Validate(object o)
{
try
{
SqlConnection temp=(SqlConnection)o;
return (!((temp.State.Equals(System.Data.ConnectionState.Closed))));
}
catch(SqlException)
{
return false;
}
}
/// <summary>
/// 销毁对象
/// </summary>
/// <param name="o"></param>
protected override void Expire(object o)
{
try
{
((SqlConnection) o).Close();
}
catch(SqlException)
{}
}
/// <summary>
/// 获取对象
/// </summary>
/// <returns></returns>
public SqlConnection BorrowDBConnection()
{
try
{
return ((SqlConnection)base.GetObjectFromPool());
}
catch(Exception ex)
{
throw ex;
}
}
/// <summary>
/// 返回对象
/// </summary>
/// <param name="e"></param>
public void ReturnDBConnection(SqlConnection e)
{
base.ReturnObjectToPool(e);
}
}
}
**********************************应用数据库连接池***************************
DBObjectPool dbPool=new DBObjectPool();
SqlConnection connection=dbPool.BorrowDBConnection();
// create a command...
System.Data.SqlClient.SqlCommand command = new System.Data.SqlClient.SqlCommand("UpdateVisitStat", connection);
mandType = mandType.StoredProcedure;
// parameters...
System.Data.SqlClient.SqlParameter companyIDParam = command.Parameters.Add("@companyID", System.Data.SqlDbType.Int);
companyIDParam.Value = companyID;
System.Data.SqlClient.SqlParameter viewURLParam = command.Parameters.Add("@viewURL", System.Data.SqlDbType.NVarChar, 200);
viewURLParam.Value = viewURL;
System.Data.SqlClient.SqlParameter depthParam = command.Parameters.Add("@depth", System.Data.SqlDbType.Int);
depthParam.Value = depth;
// execute...
command.ExecuteNonQuery();
command.Dispose();
dbPool.ReturnDBConnection(connection);//返回到池中。
// return...