帮我分析一下。加上序列化文件之后的缓存，有什么好处？

[shankaipingo]

namespace CanYouLib.Caching.FileBasedCachingProvider
{
    public class FBCachingProvider : CachingProvider
    {
        public FBCachingProvider()
        {
            _providerConfiguration = ProviderConfiguration.GetProviderConfiguration( ProviderType );
        }

        private const string ProviderType = "caching";
        private ProviderConfiguration _providerConfiguration;
        internal static string CachingDirectory = Globals.ApplicationMapPath + "\\Cache\\";
        internal const string CacheFileExtension = ".resources";
        private static System.Web.Caching.Cache _objCache;
        private static System.Web.Caching.Cache objCache
        {
            get
            {
                //create singleton of the cache object
                if( _objCache == null )
                {
                    _objCache = HttpRuntime.Cache;
                }
                return _objCache;
            }
        }
        public override object GetItem(string CacheKey)
        {
            return objCache[CacheKey];
        }

        public override object GetPersistentCacheItem( string CacheKey, Type objType )
        {
            object obj = objCache[CacheKey];
            if( obj != null )
            {
                return objCache[CacheKey];
            }
            else if( DataCache.CachePersistenceEnabled )
            {
                Stream objStream;
                string f = GetFileName( CacheKey );
                if( File.Exists( f ) )
                {
                    objStream = File.OpenRead( f );

                    XmlSerializer serializer = new XmlSerializer( objType );
                    TextReader tr = new StreamReader( objStream );
                    obj = serializer.Deserialize( tr );
                    tr.Close();
                    Insert( CacheKey, obj, true );
                }
            }
            return obj;
        }

        public override void Insert( string CacheKey, object objObject, bool PersistAppRestart )
        {
            if( PersistAppRestart )
            {
                //remove the cache key which
                //will remove the serialized
                //file before creating a new one
                Remove( CacheKey );
            }

            string f = GetFileName( CacheKey );
            CacheDependency d = new CacheDependency( f );

            if( PersistAppRestart && DataCache.CachePersistenceEnabled )
            {
                CreateCacheFile( f, objObject );
            }
            else
            {
                d = null;
            }

            objCache.Insert( CacheKey, objObject, d );
        }

        public override void Insert( string CacheKey, object objObject, CacheDependency objDependency, bool PersistAppRestart )
        {
            if( PersistAppRestart )
            {
                //remove the cache key which
                //will remove the serialized
                //file before creating a new one
                Remove( CacheKey );
            }

            string[] f = new string[1];
            f[0] = GetFileName( CacheKey );

            CacheDependency d = new CacheDependency( f, null, objDependency );
            if( PersistAppRestart && DataCache.CachePersistenceEnabled )
            {
                CreateCacheFile( f[0], objObject );
            }
             
            else
            {
                d = objDependency;
            }

            objCache.Insert( CacheKey, objObject, d );
        }

        public override void Insert( string CacheKey, object objObject, CacheDependency objDependency, DateTime AbsoluteExpiration, TimeSpan SlidingExpiration, bool PersistAppRestart )
        {
            if( PersistAppRestart )
            {
                //remove the cache key which
                //will remove the serialized
                //file before creating a new one
                Remove( CacheKey );
            }

            string[] f = new string[1];
            f[0] = GetFileName( CacheKey );

            CacheDependency d = new CacheDependency( f, null, objDependency );
            if( PersistAppRestart && DataCache.CachePersistenceEnabled )
            {
                CreateCacheFile( f[0], objObject );
            }
             
            else
            {
                d = objDependency;
            }

            objCache.Insert( CacheKey, objObject, d, AbsoluteExpiration, SlidingExpiration );
        }

        public override void Insert( string CacheKey, object objObject, CacheDependency objDependency, DateTime AbsoluteExpiration, TimeSpan SlidingExpiration, CacheItemPriority Priority, CacheItemRemovedCallback OnRemoveCallback, bool PersistAppRestart )
        {
            if( PersistAppRestart )
            {
                //remove the cache key which
                //will remove the serialized
                //file before creating a new one
                Remove( CacheKey );
            }

            string[] f = new string[1];
            f[0] = GetFileName( CacheKey );

            CacheDependency d = new CacheDependency( f, null, objDependency );
            if( PersistAppRestart && DataCache.CachePersistenceEnabled )
            {
                CreateCacheFile( f[0], objObject );
            }
           
            else
            {
                d = objDependency;
            }

            objCache.Insert( CacheKey, objObject, d, AbsoluteExpiration, SlidingExpiration, Priority, OnRemoveCallback );
        }

        public override  void Remove( string CacheKey )
        {
            if( objCache[CacheKey] != null )
            {
                objCache.Remove( CacheKey );
                string f = GetFileName( CacheKey );
               
            }
        }

         
        public override void RemovePersistentCacheItem( string CacheKey )
        {
            if( objCache[CacheKey] != null )
            {
                objCache.Remove( CacheKey );
                if( DataCache.CachePersistenceEnabled == true )
                {
                    string f = GetFileName( CacheKey );
                    DeleteCacheFile( f );
                }
            }
        }

        public override string PurgeCache()
        {
                      //省略
        }

        private int PurgeCacheFiles( string[] strFiles )
        {
                     //省略
            return PurgedFiles;
        }

        private static string GetFileName( string FileName )
        {
          //省略
        }

        private static void CreateCacheFile( string FileName )
        {
            StreamWriter s;
            if( ! File.Exists( FileName ) )
            {
                s = File.CreateText( FileName );
                if( s != null )
                {
                    s.Close();
                }
            }
        }

        private static void CreateCacheFile( string FileName, object ObjectToPersist )
        {
            string str = XmlUtils.Serialize( ObjectToPersist );

            StreamWriter s;
            if( ! File.Exists( FileName ) )
            {
                s = File.CreateText( FileName );
                s.Write( str );
                if( s != null )
                {
                    s.Close();
                }
            }
        }

        private static void DeleteCacheFile( string FileName )
        {
            if( File.Exists( FileName ) )
            {
                File.Delete( FileName );
            }
        }
    }
}

[变成熊猫你就老实了是不]

序列化主要优点有二：
1.数据以业务无关的中间形式传输，便于处理，XML就是典型的序列化方式。
2.序列化后的数据体长度缩减，节省传输资源。
与缓存配合，还可以节省box时间

[shankaipingo]

我感觉是一个三层结构
先从CACHE中拿－－－》没有就从文件中来，并更新CACHE－－－》没有文件就返回空

[shankaipingo]

姐姐。回帖要有针对性啊。估计你没有看完整。