數據庫連接池Data Connection Framework具備Connection pooling機制，能管理不同的ADO.net Connection。並通過池對象工廠去PoolObjectFactory去創建數據連接池。(可參考：對象工廠創建--- Singleton Object,SingleCall Object,Pool Object )
連接池企業應用組件圖如下：
類圖如下：
主要文件代碼：
/// <summary>
/// 連接池上下文
/// </summary>
public sealed class ConnectionPoolContext : IDisposable
{
/// <summary>
/// 池對象工廠
/// </summary>
private PoolObjectFactory _factory;
/// <summary>
/// 默認連接字符
/// </summary>
private string _defaultConnectionString;
/// <summary>
/// 工廠名稱
/// </summary>
private string _factoryName;
/// <summary>
/// 類型
/// </summary>
private Type _factoryType;
/// <summary>
/// SQL狀態倉庫
/// </summary>
private SqlStatementRepository _statementRepository;
/// <summary>
/// 連接池
/// </summary>
private static Dictionary<string, ConnectionPoolContext> _instances =
new Dictionary<string, ConnectionPoolContext>();
/// <summary>
/// 默認連接字符屬性
/// </summary>
public string DefaultConnectionString
{
get
{
return _defaultConnectionString;
}
set
{
_defaultConnectionString = value;
}
}
/// <summary>
/// 工廠名
/// </summary>
public string FactoryName
{
get
{
return _factoryName;
}
set
{
_factoryName = value;
}
}
/// <summary>
/// SQL狀態倉庫屬性
/// </summary>
public SqlStatementRepository StatementRepository
{
get
{
if (_statementRepository == null)
_statementRepository = new SqlStatementRepository();
return _statementRepository;
}
}
/// <summary>
/// 對象工廠模式
/// </summary>
internal PoolObjectFactory Factory
{
get
{
return _factory;
}
set
{
_factory = value;
}
}
/// <summary>
/// 實例化一個連接池
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
public static ConnectionPoolContext Instance(string id)
{
return _instances[id];
}
/// <summary>
/// 添加一個連接到池中
/// </summary>
/// <param name="id">id</param>
/// <param name="factoryName">工廠名稱</param>
/// <param name="connectionString">連接字符串</param>
/// <param name="max">最大數</param>
/// <param name="limit">是否限制</param>
public static void AddPool(string id, string factoryName, string
connectionString, int max, bool limit)
{
ConnectionPoolContext p = new ConnectionPoolContext();
p._defaultConnectionString = connectionString;
p._factoryName = factoryName;
p.Factory = new PoolObjectFactory(max, limit, new ArrayList());
_instances.Add(id, p);
}
/// <summary>
/// 得到一個連接
/// </summary>
/// <returns>數據庫連接</returns>
public DbConnection AcquireConnection()
{
if (_factoryType == null)
{
DbProviderFactory dbFactory = DbProviderFactories.GetFactory
(_factoryName);
DbConnection conn = dbFactory.CreateConnection();
_factoryType = conn.GetType();
}
DbConnection connection = (DbConnection)Factory.AcquireObject
(_factoryType);
if (connection.ConnectionString == string.Empty)
connection.ConnectionString = _defaultConnectionString;
return connection;
}
/// <summary>
/// 釋放一個連接
/// </summary>
/// <param name="conn">數據庫連接</param>
public void ReleaseConnection(DbConnection conn)
{
Factory.ReleaseObject(conn);
conn.Close();
}
#region IDisposable Members
/// <summary>
/// 釋放連接
/// </summary>
public void Dispose()
{
if (_factory != null)
((IDisposable)_factory).Dispose();
}
#endregion
/// <summary>
/// 私有構造函數
/// </summary>
private ConnectionPoolContext()
{
}
}
