使用 ConcurrentDictionary 和 ConcurrentBag 来管理数据库连接

using Drv.Utilities;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Data.OleDb;
using System.Linq;namespace Drv.AccessClient
{/// <summary>/// 连接池管理类/// </summary>public class MultipleConnectionPool{private ConcurrentDictionary<string, ConcurrentBag<PooledOleDbConnection>> _connectionPools;private int _maxConnectionCount;private Logger _logger;public MultipleConnectionPool(int maxConnectionCount = 5){_connectionPools = new ConcurrentDictionary<string, ConcurrentBag<PooledOleDbConnection>>();_logger = new Logger();_maxConnectionCount = maxConnectionCount;}/// <summary>/// 获取连接/// </summary>/// <param name="connectionString"></param>/// <returns></returns>public PooledOleDbConnection GetConnection(string connectionString){if (!_connectionPools.ContainsKey(connectionString)){_connectionPools[connectionString] = new ConcurrentBag<PooledOleDbConnection>();}var pool = _connectionPools[connectionString];PooledOleDbConnection availableConnection = null;// 先找已有可用连接foreach (var connection in pool){if (!connection.IsBusy && IsConnectionValid(connection.Connection)){connection.IsBusy = true;availableConnection = connection;break;}}// 没有可用连接，且连接数量小于最大连接数，则创建新连接if (availableConnection == null && pool.Count < _maxConnectionCount){try{var newConnection = new OleDbConnection(connectionString);newConnection.Open();var pooledConnection = new PooledOleDbConnection(newConnection, connectionString);pooledConnection.IsBusy = true;pool.Add(pooledConnection);availableConnection = pooledConnection;}catch (Exception ex){_logger.LogError($"创建数据库连接失败: {ex.Message}");}}else if (availableConnection == null){_logger.LogError("达到最大连接数，无法获取新的连接");}return availableConnection;}/// <summary>/// 释放连接/// </summary>/// <param name="connection"></param>public void ReleaseConnection(PooledOleDbConnection connection){if (connection != null){connection.IsBusy = false;// 可选择在连接不再使用时关闭连接// connection.Connection.Close(); // 视具体需要而定}}// 检查连接是否有效private bool IsConnectionValid(OleDbConnection connection){try{if (connection.State == System.Data.ConnectionState.Open){// 这里可以执行一个简单的查询来验证连接// connection.CreateCommand().CommandText = "SELECT 1";// connection.CreateCommand().ExecuteScalar();return true;}}catch (Exception ex){_logger.LogError($"连接无效: {ex.Message}");}return false;}}public class PooledOleDbConnection{public OleDbConnection Connection { get; }public string ConnectionString { get; }public bool IsBusy { get; set; }public PooledOleDbConnection(OleDbConnection connection, string connectionString){Connection = connection;ConnectionString = connectionString;IsBusy = false;}}
}

using Drv.Utilities;
using System;
using System.Data;
using System.Data.OleDb;namespace Drv.AccessClient
{public class SimpleDbConnectionManager : IDisposable{private OleDbConnection _connection;private string _connectionString;private bool _disposed = false; // 用于标识是否已释放资源private Logger _logger;public SimpleDbConnectionManager(string connectionString){if (string.IsNullOrWhiteSpace(connectionString)){_logger.LogError("连接字符串不能为空");}_connectionString = connectionString;_connection = new OleDbConnection(_connectionString);_logger = new Logger();}public void OpenConnection(){if (_connection.State != ConnectionState.Open){_connection.Open();}}public void CloseConnection(){if (_connection.State != ConnectionState.Closed){_connection.Close();}}public DataTable ExecuteQuery(string sql){OpenConnection();DataTable dataTable = new DataTable();try{using (OleDbCommand command = new OleDbCommand(sql, _connection)){using (OleDbDataAdapter adapter = new OleDbDataAdapter(command)){adapter.Fill(dataTable);}}}catch (Exception ex){_logger.LogError($"执行查询时发生错误: {ex.Message}\n{ex.StackTrace}");throw;}finally{CloseConnection();}return dataTable;}public void Dispose(){Dispose(true);GC.SuppressFinalize(this);}protected virtual void Dispose(bool disposing){if (!_disposed){if (disposing){CloseConnection();_connection?.Dispose();}_disposed = true;}}~SimpleDbConnectionManager(){Dispose(false); // 确保析构时也能释放资源}}
}