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以一个简易版的数据库连接池的实现来说明一下 连接池的connection以队列来管理 getConnection的时候#xff0c;如果队列中connection个数小于50#xff0c;且暂时无可用的connection#xff08;个数为0或者peek看下头部需要先出那个元素还处于不可用状态#xff09;…介绍
以一个简易版的数据库连接池的实现来说明一下 连接池的connection以队列来管理 getConnection的时候如果队列中connection个数小于50且暂时无可用的connection个数为0或者peek看下头部需要先出那个元素还处于不可用状态就新建连接并建立连接开始一直新建到50个connection就是_currentPoolSize 50 如果队列中connection个数大于等于50且暂时无可用的connection个数为0或者peek看下头部需要先出那个元素还处于不可用状态就等着Monitor.Wait(_connectionPoolQueueLock)
returnConnection的时候使用Monitor.Pulse(_connectionPoolQueueLock) 随机通知一个wait的线程可以继续getConnection了
using System;
using System.Collections.Generic;
using System.Data;
using System.Threading;
using Mono.Data.Sqlite;namespace demo.unity.sqlite
{public class SQLiteConnectionManager{private QueueTupleSqliteConnection, DateTime _connectionPoolQueue;private object _connectionPoolQueueLock new object();private const int maxPoolSize 50;private volatile bool _disposed;private int _currentPoolSize;private readonly System.Timers.Timer _cleanupTimer new System.Timers.Timer(10 * 60 * 1000);public SQLiteConnectionManager(){_connectionPoolQueue new QueueTupleSqliteConnection, DateTime(maxPoolSize);_cleanupTimer.Elapsed _cleanupTimerElapsed;_cleanupTimer.AutoReset true;_cleanupTimer.Start();}private void _cleanupTimerElapsed(object sender, System.Timers.ElapsedEventArgs e){lock (_connectionPoolQueueLock){while (_connectionPoolQueue.Count 0 (DateTime.UtcNow - _connectionPoolQueue.Peek().Item2).TotalMinutes 15){var tup _connectionPoolQueue.Dequeue();tup.Item1.Dispose();_currentPoolSize--;}}}private SqliteConnection _createNewConnection(SqliteConnectionStringBuilder builder){var connection new SqliteConnection(builder.ConnectionString);connection.Open();return connection;}public SqliteConnection getConnection(SqliteConnectionStringBuilder builder){lock (_connectionPoolQueueLock){// count 0 or queue.peek no use connectionwhile (_connectionPoolQueue.Count 0 || _connectionPoolQueue.Peek().Item1.State ! ConnectionState.Open){if (_disposed){throw new ObjectDisposedException(The DB connection pool is is already disposed);}if (_currentPoolSize maxPoolSize){// create and open connectionvar connection _createNewConnection(builder);_connectionPoolQueue.Enqueue( new TupleSqliteConnection, DateTime(connection, DateTime.UtcNow));_currentPoolSize;}else{Monitor.Wait(_connectionPoolQueueLock);}}return _connectionPoolQueue.Dequeue().Item1;}}public void returnConnection(SqliteConnection connection){if (connection null){return;}lock (_connectionPoolQueueLock){_connectionPoolQueue.Enqueue(new TupleSqliteConnection, DateTime(connection, DateTime.UtcNow));Monitor.Pulse(_connectionPoolQueueLock);}}public void dispose(){lock (_connectionPoolQueueLock){_disposed true;while (_connectionPoolQueue.Count 0){var tup _connectionPoolQueue.Dequeue();tup.Item1?.Dispose();_currentPoolSize--;}// wake up any waiting threadsMonitor.PulseAll(_connectionPoolQueueLock);}_cleanupTimer.Stop();_cleanupTimer.Dispose();}}
}
