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, 0);
        }

        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, 60);
            }
            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="120" maximumElementsInCacheBeforeScavenging="1000" numberToRemoveWhenScavenging="10" 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>