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站架构之缓存应用
这篇来讲如何利用memcached实现一级缓存，以及如何让一级缓存组件支持在企业库，memcached或者其它第三方实施方案之间的切换。memcached本人并没有太多经验，如果文中有说的不对的地方，还希望批评指出，且文中关于memcached的代码大多来自网络。 
private void Setup()
{ String[] serverlist = { "127.0.0.1:11211" }; this._pool = SockIOPool.GetInstance("default"); this._pool.SetServers(serverlist); //设置服务器列 //各服务器之间负载均衡的设置 this._pool.SetWeights(new int[] { 1 }); //socket pool设置 this._pool.InitConnections = 5; //初始化时创建的连接数 this._pool.MinConnections = 5; //最小连接数 this._pool.MaxConnections = 250; //最大连接数 //连接的最大空闲时间，下面设置为6个小时（单位ms），超过这个设置时间，连接会被释放掉 this._pool.MaxIdle = 1000 * 60 * 60 * 6; //通讯的超时时间，下面设置为3秒（单位ms），.NET版本没有实现 this._pool.SocketTimeout = 1000 * 3; //socket连接的超时时间，下面设置表示连接不超时，即一直保持连接状态 this._pool.SocketConnectTimeout = 0; this._pool.Nagle = false; //是否对TCP/IP通讯使用Nalgle算法，.NET版本没有实现 //维护线程的间隔激活时间，下面设置为60秒（单位s），设置为0表示不启用维护线程 this._pool.MaintenanceSleep = 60; //socket单次任务的最大时间，超过这个时间socket会被强行中断掉（当前任务失败） this._pool.MaxBusy = 1000 * 10; this._pool.Initialize(); } 2:获取一个memcached客户端。 private MemcachedClient GetClient()
{ MemcachedClient client = new MemcachedClient(); client.PoolName = "default"; return client; } 3：根据memcached提供的功能实现IWebCacheProvider，代码就不贴了，大家可以自己去试试。 1:LocalCacheOnlyMode,只启用web server上的二级缓存。 2:BufferedLCacheServerMode,即启用web server上的二级缓存也启用cache server上的缓存。 3:Off,关闭缓存功能。  代码
/// <summary>
/// 获取一级缓存 /// </summary> /// <param name="hashKey"></param> /// <param name="configFilePath"></param> /// <returns></returns> private IWebCacheProvider GetPrimaryCacheProvider(uint hashKey) { IWebCacheProvider provider = null; string cacheType = WebConfig.ChannelConfig["CacheType"].ToString().ToLower(); switch (cacheType) { case "memcached": provider = WebCacheProviderFactory.GetMemcachedWebCacheProvider(configFilePath); break; case "entlib": provider = servicePool.GetServiceClient(hashKey) as IWebCacheProvider; break; } return provider; } 插入缓存的逻辑：原理就是根据配置文件中的CacheMode来完成缓存级别的判定以及一级缓存的方案。 代码
public void Insert(string key, object value, string region, string subRegion, CacheItemConfig cacheItemConfig)
{ if (string.IsNullOrEmpty(key) || value == null) return; //关闭模式，不使用缓存 if (Options.CacheServiceMode == ECacheServiceMode.Off) { return; } else if (Options.CacheServiceMode == ECacheServiceMode.BufferedLCacheServerMode || Options.CacheServiceMode == ECacheServiceMode.LocalAndCacheServerAndSql || Options.CacheServiceMode == ECacheServiceMode.LocalCacheOnlyMode) {//使用带缓冲的模式 if (Options.BufferType == ECacheDependencyType.SlidingTime) { SecondaryCacheProvider.Insert(key, value, region, subRegion, MyCacheItemPriority.Normal, Options.BufferSlidingTime); } else if (Options.BufferType == ECacheDependencyType.AbsoluteTime) { SecondaryCacheProvider.Insert(key, value, region, subRegion, MyCacheItemPriority.Normal, Options.BufferAbsoluteTime); } if (Options.CacheServiceMode == ECacheServiceMode.LocalCacheOnlyMode) {//只使用本地缓存 return; } } checkKey(key); uint hashKey = hash(key); try { if (Options.CacheServiceMode == ECacheServiceMode.CacheServerMode || Options.CacheServiceMode == ECacheServiceMode.BufferedLCacheServerMode || Options.CacheServiceMode == ECacheServiceMode.CacheServerAndSql || Options.CacheServiceMode == ECacheServiceMode.LocalAndCacheServerAndSql) {//CacheServer模式使用Cache服务器保存Cache IWebCacheProvider service = this .GetPrimaryCacheProvider(hashKey); byte[] byteValue = SerializationHelper.SaveToBinaryBytes(value); var cachePriority = ModelConverter.ToRefClass(cacheItemConfig.CachePriority); if (cacheItemConfig.CacheType == ECacheDependencyType.AbsoluteTime) { AbsoluteTimeCacheDependency absTime = new AbsoluteTimeCacheDependency(); absTime.AbsoluteTime = DateTime.Now.AddMinutes(cacheItemConfig.CacheTimeMinutes); service.Insert(key, byteValue, region, subRegion, cachePriority, absTime); } else if (cacheItemConfig.CacheType == ECacheDependencyType.SlidingTime) { SlidingTimeCacheDependency slTime = new SlidingTimeCacheDependency(); slTime.SlidingTime = new TimeSpan(0, cacheItemConfig.CacheTimeMinutes, 0); service.Insert(key, byteValue, region, subRegion, cachePriority, slTime); } } } catch (Exception ex) {//出现异常，保存到数据库中 servicePool.ReplaceServiceClient(hashKey); this.SendLogEmail(ex); } } 客户端调用代码：为了调用方便，创建一个CacheHelper来帮助完成： 代码
public class CacheHelper
{ /// <summary> /// 主分区 /// </summary> public const string REGION = "MyBlog"; /// <summary> /// 子分区 /// </summary> public const string SUB_REGION = "default"; public const string BlogListConfigKey = "BlogListConfigKey"; #region 页面间数据传递 /// <summary> /// 新增页面间传递数据到WebCache /// </summary> /// <returns>返回PageKeyID，用于页面间传递的键值</returns> public static string InsertPageParams(string configKey, object obj,string pageKey) { string result = null; MyWebCacheServiceClient cacheClient = CacheClientFactory.GetWebCacheServiceClient(REGION, SUB_REGION, configKey); cacheClient.Insert( MyWebCacheServiceClient.BuildKey(configKey,pageKey), obj, REGION, SUB_REGION); return result; } /// <summary> /// 从Cache里获取页面传递Cache /// </summary> /// <param name="key">FlightCacheKey里的常量</param> /// <param name="pageKeyID">页面传递的键值</param> public static object GetPageParams(string configKey, string pageKey) { object result = null; MyWebCacheServiceClient cacheClient = CacheClientFactory.GetWebCacheServiceClient(REGION, SUB_REGION, configKey); result = cacheClient.Get( MyWebCacheServiceClient.BuildKey(configKey, pageKey), REGION, SUB_REGION); return result; } #endregion } 两级缓存类结构图： 以上代码贴出来看起来有点乱，这里贴出网站两级缓存类结构图： |
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