.NET中的本地缓存（数据分拆+lock锁）

using System; using System.Collections.Generic; using System.Threading; using System.Threading.Tasks;  namespace MyCache {     /// <summary>     /// 第三方数据存储和获取的地方     ///      /// 过期策略：     ///     永久有效     ///     绝对过期---有个时间点，超过就过期     ///     滑动过期---多久之后过期，如果期间更新/查询/检查存在，就再次延长     ///      /// 主动清理+被动清理，保证过期数据不会被查询；过期数据也不会滞留太久     ///      /// 多线程操作非线程安全的容器，会造成冲突，那有什么解决方案呢？     ///     1、使用线程安全容器ConcurrentDictionary     ///     2、用lock---Add/Remove/遍历 解决问题了，但是性能怎么办呢？     ///     怎么降低影响，提升性能呢？ --- 数据分拆，多个数据容器，多个锁，容器之间可以并发。     /// </summary>     public class CustomCache     {         #region 字段和属性          /// <summary>         /// 模拟获取系统的CPU数         /// </summary>         private static int _cpuNumer = 0;          /// <summary>         /// 动态初始化多个容器         /// </summary>         private static List<Dictionary<string, object>> _dictionaryList = new List<Dictionary<string, object>>();          /// <summary>         /// 动态初始化多个锁         /// </summary>         private static List<object> _lockList = new List<object>();          #endregion 字段和属性          #region 静态构造函数          /// <summary>         /// 静态构造函数         /// </summary>         static CustomCache()         {             _cpuNumer = 4;             for (int i = 0; i < _cpuNumer; i++)             {                 _dictionaryList.Add(new Dictionary<string, object>());                 _lockList.Add(new object());             }              //主动清理缓存             Task.Run(() =>             {                 while (true)                 {                     Thread.Sleep(1000 * 60 * 10);                     try                     {                         for (int i = 0; i < _cpuNumer; i++)                         {                             List<string> keyList = new List<string>();                             lock (_lockList[i]) //数据分拆，减少锁的影响范围                             {                                 foreach (var key in _dictionaryList[i].Keys)                                 {                                     DataModel model = (DataModel)_dictionaryList[i][key];                                     if (model.ObsloteType != ObsloteType.Never && model.DeadLine < DateTime.Now)                                     {                                         keyList.Add(key);                                     }                                 }                                 keyList.ForEach(s => _dictionaryList[i].Remove(s));                             }                         }                     }                     catch (Exception ex)                     {                         Console.WriteLine(ex.ToString());                         continue;                     }                 }             });         }          #endregion 静态构造函数          /// <summary>         /// 获取容器索引         /// </summary>         /// <param name="key">缓存键</param>         /// <returns>索引值</returns>         public static int GetHashCodeIndex(string key)         {             int hash = Math.Abs(key.GetHashCode()); //相对均匀而且稳定             return hash % _cpuNumer;         }          /// <summary>         /// 添加         /// </summary>         /// <param name="key">缓存键</param>         /// <param name="oValue">缓存值</param>         public static void Add(string key, object oValue)         {             int index = GetHashCodeIndex(key);             lock (_lockList[index])             {                 _dictionaryList[index].Add(key, new DataModel()                 {                     Value = oValue,                     ObsloteType = ObsloteType.Never                 });             }         }          /// <summary>         /// 绝对过期         /// </summary>         /// <param name="key">缓存键</param>         /// <param name="oVaule">缓存值</param>         /// <param name="timeOutSecond">过期时间</param>         public static void Add(string key, object oVaule, int timeOutSecond)         {             int index = GetHashCodeIndex(key);             lock (_lockList[index])             {                 _dictionaryList[index].Add(key, new DataModel()                 {                     Value = oVaule,                     ObsloteType = ObsloteType.Absolutely,                     DeadLine = DateTime.Now.AddSeconds(timeOutSecond)                 });             }         }          /// <summary>         /// 相对过期         /// </summary>         /// <param name="key">缓存键</param>         /// <param name="oVaule">缓存值</param>         /// <param name="duration">过期时间</param>         public static void Add(string key, object oVaule, TimeSpan duration)         {             int index = GetHashCodeIndex(key);             lock (_lockList[index])             {                 _dictionaryList[index].Add(key, new DataModel()                 {                     Value = oVaule,                     ObsloteType = ObsloteType.Relative,                     DeadLine = DateTime.Now.Add(duration),                     Duration = duration                 });             }         }          /// <summary>         /// 获取数据（要求在Get前做Exists检测）         /// </summary>         /// <typeparam name="T">类型</typeparam>         /// <param name="key">缓存键</param>         /// <returns>缓存值</returns>         public static T Get<T>(string key)         {             int index = GetHashCodeIndex(key);             return (T)((DataModel)_dictionaryList[index][key]).Value;         }          /// <summary>         /// 判断缓存是否存在（被动清理，请求了数据，才能清理）         /// </summary>         /// <param name="key">缓存键</param>         /// <returns></returns>         public static bool Exists(string key)         {             int index = GetHashCodeIndex(key);             if (_dictionaryList[index].ContainsKey(key))             {                 DataModel model = (DataModel)_dictionaryList[index][key];                 if (model.ObsloteType == ObsloteType.Never)                 {                     return true;                 }                 else if (model.DeadLine < DateTime.Now) //现在已经超过你的最后时间                 {                     lock (_lockList[index])                     {                         //被动清理，请求了数据，才能清理                         _dictionaryList[index].Remove(key);                     }                      return false;                 }                 else                 {                     if (model.ObsloteType == ObsloteType.Relative) //没有过期&是滑动 所以要更新                     {                         model.DeadLine = DateTime.Now.Add(model.Duration);                     }                      return true;                 }             }             else             {                 return false;             }         }          /// <summary>         /// 移除缓存         /// </summary>         /// <param name="key">缓存键</param>         public static void Remove(string key)         {             int index = GetHashCodeIndex(key);             lock (_lockList[index])             {                 _dictionaryList[index].Remove(key);             }         }          /// <summary>         /// 移除所有缓存         /// </summary>         public static void RemoveAll()         {             for (int index = 0; index < _cpuNumer; index++)             {                 lock (_lockList[index])                 {                     _dictionaryList[index].Clear();                 }             }         }          /// <summary>         /// 按条件移除         /// </summary>         /// <param name="func">条件表达式</param>         public static void RemoveCondition(Func<string, bool> func)         {             for (int i = 0; i < _cpuNumer; i++)             {                 List<string> keyList = new List<string>();                 lock (_lockList[i])                 {                     foreach (var key in _dictionaryList[i].Keys)                     {                         if (func.Invoke(key))                         {                             keyList.Add(key);                         }                     }                     keyList.ForEach(s => Remove(s));                 }             }         }          public static T GetT<T>(string key, Func<T> func)         {             T t;             if (!Exists(key))             {                 t = func.Invoke();                 Add(key, t);             }             else             {                 t = Get<T>(key);             }              return t;         }     }      /// <summary>     /// 缓存的信息     /// </summary>     internal class DataModel     {         public object Value { get; set; }         public ObsloteType ObsloteType { get; set; }         public DateTime DeadLine { get; set; }         public TimeSpan Duration { get; set; }          /// <summary>         /// 数据清理后出发事件         /// </summary>         public event Action DataClearEvent;     }      /// <summary>     /// 缓存策略     /// </summary>     public enum ObsloteType     {         /// <summary>         /// 永久         /// </summary>         Never,          /// <summary>         /// 绝对过期         /// </summary>         Absolutely,          /// <summary>         /// 相对过期         /// </summary>         Relative     } }

using System; using System.Collections.Generic; using System.Threading.Tasks;  namespace MyCache {     /// <summary>     /// 系统性能优化的第一步，就是使用缓存。     /// </summary>     class Program     {         static void Main(string[] args)         {             try             {                 {                     //多线程问题                     List<Task> taskList = new List<Task>();                     for (int i = 0; i < 1_000_000; i++)                     {                         int k = i;                         taskList.Add(Task.Run(() => CustomCache.Add($"TestKey_{k}", $"TestValue_{k}", 10)));                     }                      for (int i = 0; i < 100; i++)                     {                         int k = i;                         taskList.Add(Task.Run(() =>                         {                             if (k % 10 == 0)                             {                                 Console.WriteLine(CustomCache.Get<string>($"TestKey_{k}"));                             }                              CustomCache.Remove($"TestKey_{k}");                              if (k % 10 == 0)                             {                                 Console.WriteLine($"TestKey_{k}_Exists:{CustomCache.Exists($"TestKey_{k}")}");                             }                         }));                     }                      for (int i = 0; i < 100; i++)                     {                         int k = i;                         taskList.Add(Task.Run(() =>                         {                             CustomCache.Exists($"TestKey_{k}");                         }));                     }                      Task.WaitAll(taskList.ToArray());                 }             }             catch (Exception ex)             {                 Console.WriteLine(ex.ToString());             }              Console.ReadKey();         }     } }

链接：https://pan.baidu.com/s/1GhLCBEaLqVL4wptjtZBSPQ  提取码：u9fe