本文定义 ICache 接口，以及实现默认的 ASP.NET 缓存机制（即通过 System.Web.Caching.Cache）来缓存，将来也可以通过扩展，替换默认实现。
下面直接贴代码了：
ICache 接口
基础接口 - ICache
using System;
using System.Collections;
using System.Collections.Generic; public interface ICache
{
void Clear();
bool Contains(string key);
object Get(object key);
T Get<T>(object key);
IList<CacheItemDescriptor> GetDescriptors();
T GetOrInsert<T>(object key, int timeToLiveInSeconds, bool slidingExpiration, Func<T> fetcher);
void Insert(object key, object value);
void Insert(object key, object value, int timeToLive, bool slidingExpiration);
void Insert(object key, object value, int timeToLive, bool slidingExpiration, CacheItemPriority priority);
void Remove(object key);
void RemoveAll(ICollection keys); int Count { get; } ICollection Keys { get; }
}
结束标记。
CacheAspNet
依赖 Web 运行时的缓存
using System;
using System.Collections;
using System.Collections.Generic;
using System.Web;
using System.Web.Caching; public class CacheAspNet : ICache
{
private Cache _cache;
private CacheSettings _settings; public CacheAspNet()
{
this._settings = new CacheSettings();
this.Init(new CacheSettings());
} public CacheAspNet(CacheSettings settings)
{
this._settings = new CacheSettings();
this.Init(settings);
} private string BuildKey(object key)
{
if (this._settings.UsePrefix) return (this._settings.PrefixForCacheKeys + "." + key.ToString());
return key.ToString();
} public void Clear()
{
ICollection keys = this.Keys;
foreach (string str in keys)
{
string key = this.BuildKey(str);
this._cache.Remove(key);
}
} public bool Contains(string key)
{
string str = this.BuildKey(key);
if (this._cache.Get(str) == null) return false;
return true;
} private System.Web.Caching.CacheItemPriority ConvertToAspNetPriority(CacheItemPriority priority)
{
if (priority == CacheItemPriority.Normal) return System.Web.Caching.CacheItemPriority.Normal;
if (priority == CacheItemPriority.High) return System.Web.Caching.CacheItemPriority.High;
if (priority == CacheItemPriority.Low) return System.Web.Caching.CacheItemPriority.Low;
if (priority == CacheItemPriority.Normal) return System.Web.Caching.CacheItemPriority.Normal;
return System.Web.Caching.CacheItemPriority.NotRemovable;
} public T Get<T>(object key)
{
string str = this.BuildKey(key);
object obj2 = this._cache.Get(str);
if (obj2 == null) return default(T);
return (T) obj2;
} public object Get(object key)
{
string str = this.BuildKey(key);
return this._cache.Get(str);
} public IList<CacheItemDescriptor> GetDescriptors()
{
IList<CacheItemDescriptor> list = new List<CacheItemDescriptor>();
IEnumerator enumerator = this.Keys.GetEnumerator();
while (enumerator.MoveNext())
{
string current = enumerator.Current as string;
object obj2 = this.Get(current);
list.Add(new CacheItemDescriptor(current, obj2.GetType().FullName));
}
((List<CacheItemDescriptor>) list).Sort((Comparison<CacheItemDescriptor>) ((c1, c2) => c1.Key.CompareTo(c2.Key)));
return list;
} public T GetOrInsert<T>(object key, int timeToLiveInSeconds, bool slidingExpiration, Func<T> fetcher)
{
object obj2 = this.Get(key);
if (obj2 == null)
{
T local = fetcher();
this.Insert(key, local, timeToLiveInSeconds, slidingExpiration);
return local;
}
return (T) obj2;
} private void Init(CacheSettings settings)
{
this._cache = HttpRuntime.Cache;
this._settings = settings;
} public void Insert(object key, object value)
{
this.Insert(key, value, this._settings.DefaultTimeToLive, this._settings.DefaultSlidingExpirationEnabled, this._settings.DefaultCachePriority);
} public void Insert(object key, object value, int timeToLive, bool slidingExpiration)
{
this.Insert(key, value, timeToLive, slidingExpiration, this._settings.DefaultCachePriority);
} public void Insert(object keyName, object value, int timeToLive, bool slidingExpiration, CacheItemPriority priority)
{
TimeSpan span = TimeSpan.FromSeconds((double) timeToLive);
if (keyName == null)
{
throw new ArgumentNullException("keyName");
}
if(TimeSpan.Zero > span)
{
throw new ArgumentException("timeToLive");
}
System.Web.Caching.CacheItemPriority priority2 = this.ConvertToAspNetPriority(priority);
string key = this.BuildKey(keyName);
if (TimeSpan.Zero < span)
{
if (slidingExpiration)
{
this._cache.Insert(key, value, null, Cache.NoAbsoluteExpiration, span, priority2, null);
}
else
{
DateTime absoluteExpiration = DateTime.Now.AddSeconds((double)timeToLive);
this._cache.Insert(key, value, null, absoluteExpiration, Cache.NoSlidingExpiration, priority2, null);
}
}
else
{
this._cache.Insert(key, value, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, priority2, null);
}
} public void Remove(object key)
{
string str = this.BuildKey(key);
this._cache.Remove(str);
} public void RemoveAll(ICollection keys)
{
foreach (object obj2 in keys)
{
string key = this.BuildKey((string) obj2);
this._cache.Remove(key);
}
} public int Count
{
get
{
if (!this._settings.UsePrefix) return this._cache.Count;
int num = ;
foreach (DictionaryEntry entry in this._cache)
{
string key = (string) entry.Key;
if (key.StartsWith(this._settings.PrefixForCacheKeys))
{
num++;
}
}
return num;
}
} public ICollection Keys
{
get
{
IList<string> list = new List<string>();
foreach (DictionaryEntry entry in this._cache)
{
string key = (string) entry.Key;
if (!this._settings.UsePrefix)
{
list.Add(key);
}
else if (key.StartsWith(this._settings.PrefixForCacheKeys))
{
list.Add(key.Substring(this._settings.PrefixForCacheKeys.Length + ));
}
}
return (list as ICollection);
}
} public CacheSettings Settings
{
get
{
return this._settings;
}
}
}
CacheItemPriority.cs
using System; public enum CacheItemPriority
{
Default = ,
High = ,
Low = ,
Normal = ,
NotRemovable =
}
CacheItemDescriptor.cs
using System; public class CacheItemDescriptor
{
private string _key;
private string _serializedData;
private string _type; public CacheItemDescriptor(string key, string type) : this(key, type, string.Empty)
{
} public CacheItemDescriptor(string key, string type, string serializedData)
{
this._serializedData = string.Empty;
this._key = key;
this._type = type;
this._serializedData = serializedData;
} public string Data
{
get
{
return this._serializedData;
}
} public string ItemType
{
get
{
return this._type;
}
} public string Key
{
get
{
return this._key;
}
}
}
CacheSettings.cs
using System; public class CacheSettings
{
public CacheItemPriority DefaultCachePriority = CacheItemPriority.Normal;
public bool DefaultSlidingExpirationEnabled = false;
public int DefaultTimeToLive = ;
public string PrefixForCacheKeys = "cmnlib";
public bool UsePrefix = true;
}
Cacher.cs
using System;
using System.Collections;
using System.Collections.Generic; public class Cacher
{
private static ICache _provider = new CacheAspNet(); public static void Clear()
{
_provider.Clear();
} public static bool Contains(string key)
{
return _provider.Contains(key);
} public static object Get(object key)
{
return _provider.Get(key);
} public static T Get<T>(object key)
{
return _provider.Get<T>(key);
} public static T Get<T>(string key, int timeInSeconds, Func<T> fetcher)
{
return Get<T>(key, true, timeInSeconds, false, fetcher);
} public static T Get<T>(string key, TimeSpan timeInSeconds, Func<T> fetcher)
{
return Get<T>(key, true, timeInSeconds.Seconds, false, fetcher);
} public static T Get<T>(string key, bool useCache, TimeSpan timeInSeconds, Func<T> fetcher)
{
return Get<T>(key, useCache, timeInSeconds.Seconds, false, fetcher);
} public static T Get<T>(string key, bool useCache, int timeInSeconds, bool slidingExpiration, Func<T> fetcher)
{
if (!useCache) return fetcher();
return _provider.GetOrInsert<T>(key, timeInSeconds, slidingExpiration, fetcher);
} public static IList<CacheItemDescriptor> GetDescriptors()
{
return _provider.GetDescriptors();
} public static void Init(ICache cacheProvider)
{
_provider = cacheProvider;
} public static void Insert(object key, object value)
{
_provider.Insert(key, value);
} public static void Insert(object key, object value, int timeToLive, bool slidingExpiration)
{
_provider.Insert(key, value, timeToLive, slidingExpiration);
} public static void Insert(object key, object value, int timeToLive, bool slidingExpiration, CacheItemPriority priority)
{
_provider.Insert(key, value, timeToLive, slidingExpiration, priority);
} public static void Remove(object key)
{
_provider.Remove(key);
} public static void RemoveAll(ICollection keys)
{
_provider.RemoveAll(keys);
} public static int Count
{
get
{
return _provider.Count;
}
} public static ICollection Keys
{
get
{
return _provider.Keys;
}
} public static ICache Provider
{
get
{
return _provider;
}
}
}
结束标记。
RuntimeMomoryCache
备注：.NET 4.0 增加了一个 System.Runtime.Caching.Momory 类，不依赖 Web。
代码如下：
public class RuntimeMemoryCache : ICache
{
// Fields
private readonly MemoryCache _cache = MemoryCache.Default; // Methods
public void Add(string key, object value, TimeSpan timeSpan)
{
if (!string.IsNullOrEmpty(key) && value != null) this._cache.Add(key, value, DateTimeOffset.Now.Add(timeSpan), null);
} public void AddWithFileDependency(string key, object value, string fullFileNameOfFileDependency)
{
if (!string.IsNullOrEmpty(key) && value != null)
{
CacheItemPolicy policy = new CacheItemPolicy {
AbsoluteExpiration = DateTimeOffset.Now.AddMonths()
};
policy.ChangeMonitors.Add(new HostFileChangeMonitor(new List<string> { fullFileNameOfFileDependency }));
this._cache.Add(key, value, policy, null);
}
} public void Clear()
{
foreach (string str in this._cache.AsParallel<KeyValuePair<string, object>>().ToDictionary<KeyValuePair<string, object>, string>(a => a.Key).Keys)
{
this._cache.Remove(str, null);
}
} public object Get(string cacheKey)
{
return this._cache[cacheKey];
} public void MarkDeletion(string key, object value, TimeSpan timeSpan)
{
this.Remove(key);
} public void Remove(string cacheKey)
{
this._cache.Remove(cacheKey, null);
} public void Set(string key, object value, TimeSpan timeSpan)
{
this._cache.Set(key, value, DateTimeOffset.Now.Add(timeSpan), null);
}
}
结束标记。
分布式缓存 - Memcached
利用 Memcached 实现分布式缓存。
MemcachedClient 使用的是 Enyim.Caching。开源地址：https://github.com/enyim/EnyimMemcached
public class MemcachedCache : ICache
{
// Fields
private MemcachedClient cache = new MemcachedClient(); // Methods
public void Add(string key, object value, TimeSpan timeSpan)
{
key = key.ToLower();
this.cache.Store(, key, value, DateTime.Now.Add(timeSpan));
} public void AddWithFileDependency(string key, object value, string fullFileNameOfFileDependency)
{
this.Add(key, value, new TimeSpan(, , , ));
} public void Clear()
{
this.cache.FlushAll();
} public object Get(string cacheKey)
{
cacheKey = cacheKey.ToLower();
HttpContext current = HttpContext.Current;
if (current != null && current.Items.Contains(cacheKey)) return current.Items[cacheKey];
object obj2 = this.cache.Get(cacheKey);
if (current != null && obj2 != null) current.Items[cacheKey] = obj2;
return obj2;
} public Dictionary<string, Dictionary<string, string>> GetStatistics()
{
throw new NotImplementedException();
} public void MarkDeletion(string key, object value, TimeSpan timeSpan)
{
this.Set(key, value, timeSpan);
} public void Remove(string cacheKey)
{
cacheKey = cacheKey.ToLower();
this.cache.Remove(cacheKey);
} public void Set(string key, object value, TimeSpan timeSpan)
{
this.Add(key, value, timeSpan);
}
}
谢谢浏览！