memcached缓存机制+微软缓存机制使用详解

1、 why Memcached

1.1   一台web服务器上，iis接收的请求数是有限的，当访问量超大的时候，网站访问就会遇到瓶颈了，处理方式就是运用多了服务器把请求数分流（集群），对外公布的就一个公共的ip。

1.2   当数据访问量有10w时候，通过3台服务器分流请求，每台即承担了3.3w个请求，当用户登录的时候，如何共享登录信息就成为需要解决的问题（如把登录信息放到数据库中，性能会很差），这就是分布式缓存的运用场景。

2、 Memcached基本介绍

2.1 key最大：255字节，value最大：1m，{key:key1,value:123}

3、Windows下使用Memcache

3.1 下载memcache：www.code.jellycan.com/Memcache

3.2 安装服务：cmd---Memcached.exe –d install

3.3 启动服务：cmd---Memcached.exe –d start (restart 重启，stop关闭)

3.4 检查服务是否启动：连接到Memcache控制台：telnet 127.0.0.1 11211，回车，输入命令：stats 检查当前服务状态。

3.5 卸载Memcached.exe –d uninstall

遇到问题：如无法启动此程序，解决方法：下载MSVCR71.dll，安装上即可。

3.6 增删改查输命令方式

3.6.1 add keyname 0 0 5 回车 //第一个0是一个数字，第二个是过期时间，单位秒，0表示不限期，5表示value长度，如keyname存在，则不做操作

12345 //value内容

3.6.2 get keyname //得到相应的value的值

3.6.3 delete keyname //删除

3.6.4 set keyname 0 0 5 回车 //如果没有则添加，如有就更新

12345

3、 c#下操作memcache

4、 微软缓存方式

demo

业务逻辑层：

接口：ICacheManager

 public interface ICacheManager
     {
         object Get(string key);
         void Set(string key, object value);
         void Set(string key, object value, int timeout);
         void Remove(string key);
         void RemoveAll();
     }

CacheFactory类：

 public class CacheFactory
     {
         private static ICacheManager _instance = null;
         private static object m_LockObj = new object();
         private CacheFactory() { }
         static CacheFactory()
         {
             GetInstance();
         }
         public static ICacheManager GetInstance()
         {
             if (_instance == null)
             {
                 lock (m_LockObj)
                 {
                     if (_instance == null)
                     {
                         string cacheType = ConfigurationSettings.AppSettings["CacheType"];
                         if (cacheType == "MemCacheManager")
                             _instance = new MemCachedManager();
                         else
                             _instance = new MsCacheManager();
                     }
                 }
             }
             return _instance;
         }
     }

MemCachedManager类：

 public class MemCachedManager: ICacheManager
     {
         private MemcachedClient m_CacheManager;

         public MemCachedManager()
         {
             m_CacheManager = MemcachedClient.GetInstance("CachePS");
         }
         public void Set(string key, object value)
         {
             m_CacheManager.Set(key, value);
         }
         public void Set(string key, object value, int timeout)
         {
             m_CacheManager.Set(key, value, DateTime.Now.AddMinutes(timeout));
         }
         public object Get(string key)
         {
             return m_CacheManager.Get(key);
         }
         public void Remove(string key)
         {
             m_CacheManager.Delete(key);
         }
         public void RemoveAll()
         {
             m_CacheManager.FlushAll();
         }
     }

MsCacheManager类：

 public class MsCacheManager : ICacheManager
     {
         private BaseCacheDAL m_CacheManager;

         public MsCacheManager()
         {
             m_CacheManager = new BaseCacheDAL("CachePS");
         }

         public object Get(string key)
         {
             return m_CacheManager.GetCache(key);
         }

         public void Set(string key, object value)
         {
             m_CacheManager.SetCache(key, value, );
         }

         public void Set(string key, object value, int timeout)
         {
             m_CacheManager.SetCache(key, value, timeout);
         }

         public void Remove(string key)
         {
             m_CacheManager.Remove(key);
         }

         public void RemoveAll()
         {
             m_CacheManager.RemoveAll();
         }
     }

调用：

  public static DataTable GetCarPList(int UserId)
         {
             DataTable dt;
             dt = cacheManger.Get(CacheKey.GetCarPList_Key()) as DataTable;
             if (dt == null)
             {
                 string sql = string.Format("select C.CarId,C.ProId,C.UserId,C.BuyNumber,P.ProName,P.Price,P.ProImage,P.Stock  from Car C inner join Product P on C.ProId=P.ProId where C.UserId={0}", UserId);
                 dt = SqlHelper.ExecuteDataTable(com.Model.Base.DataBaseEnum.ruanmou, sql, CommandType.Text, null);
                 cacheManger.Set(CacheKey.GetCarPList_Key(), dt, );
             }
             return dt;
         }

web.config重要节点配置：

 <appSettings>
     <add key="CacheType" value="MsCacheManager"/>
     <!--<add key="CacheType" value="MemCacheManager"/>-->
   </appSettings>

 <configSections>
     <section name="dataConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Data.Configuration.DatabaseSettings, Microsoft.Practices.EnterpriseLibrary.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
     <section name="cachingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Caching.Configuration.CacheManagerSettings, Microsoft.Practices.EnterpriseLibrary.Caching, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
     <section name="enterpriseLibrary.ConfigurationSource" type="Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ConfigurationSourceSection, Microsoft.Practices.EnterpriseLibrary.Common, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
     <section name="memcachedgarden" type="System.Configuration.NameValueSectionHandler"/>
   </configSections>

 <cachingConfiguration defaultCacheManager="CachePS">
     <cacheManagers>
       <add expirationPollFrequencyInSeconds="" maximumElementsInCacheBeforeScavenging="" numberToRemoveWhenScavenging="" backingStoreName="Null Storage" type="Microsoft.Practices.EnterpriseLibrary.Caching.CacheManager, Microsoft.Practices.EnterpriseLibrary.Caching, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" name="CachePS"/>
     </cacheManagers>
     <backingStores>
       <add encryptionProviderName="" type="Microsoft.Practices.EnterpriseLibrary.Caching.BackingStoreImplementations.NullBackingStore, Microsoft.Practices.EnterpriseLibrary.Caching, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" name="Null Storage"/>
     </backingStores>
   </cachingConfiguration>
   <enterpriseLibrary.ConfigurationSource selectedSource="System Configuration Source">
     <sources>
       <add name="System Configuration Source" type="Microsoft.Practices.EnterpriseLibrary.Common.Configuration.SystemConfigurationSource, Microsoft.Practices.EnterpriseLibrary.Common, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
     </sources>
   </enterpriseLibrary.ConfigurationSource>
   <memcachedgarden>
     <add key="CachePS" value="127.0.0.1:11211"/>
   </memcachedgarden>