C# 記憶體快取工具類 MemoryCacheUtil
阿新 • • 發佈:2021-08-06
C# 記憶體快取工具類 MemoryCacheUtil
using System; using System.Collections.Concurrent; using System.Collections.Generic; using System.Linq; using System.Security.Cryptography; using System.Text; using System.Threading.Tasks; using System.Timers; namespace Utils { /// <summary> /// 快取 /// 快取資料儲存在記憶體中View Code/// 適用於CS專案,BS專案慎用 /// </summary> public static class MemoryCacheUtil { #region 變數 /// <summary> /// 記憶體快取 /// </summary> private static ConcurrentDictionary<string, CacheData> _cacheDict = new ConcurrentDictionary<string, CacheData>();/// <summary> /// 對不同的鍵提供不同的鎖,用於讀快取 /// </summary> private static ConcurrentDictionary<string, string> _dictLocksForReadCache = new ConcurrentDictionary<string, string>(); /// <summary> /// 過期快取檢測Timer /// </summary> private staticTimer _timerCheckCache; #endregion #region 靜態建構函式 static MemoryCacheUtil() { _timerCheckCache = new Timer(); _timerCheckCache.Interval = 60 * 1000; _timerCheckCache.Elapsed += _timerCheckCache_Elapsed; _timerCheckCache.Start(); } #endregion #region 獲取並快取資料 /// <summary> /// 獲取並快取資料 /// 高併發的情況建議使用此過載函式,防止重複寫入記憶體快取 /// </summary> /// <param name="cacheKey">鍵</param> /// <param name="func">在此方法中初始化資料</param> /// <param name="expirationSeconds">快取過期時間(秒),0表示永不過期</param> /// <param name="refreshCache">立即重新整理快取</param> public static T TryGetValue<T>(string cacheKey, Func<T> func, int expirationSeconds = 0, bool refreshCache = false) { lock (_dictLocksForReadCache.GetOrAdd(cacheKey, cacheKey)) { object cacheValue = MemoryCacheUtil.GetValue(cacheKey); if (cacheValue != null && !refreshCache) { return (T)cacheValue; } else { T value = func(); MemoryCacheUtil.SetValue(cacheKey, value, expirationSeconds); return value; } } } #endregion #region SetValue 儲存鍵值對 /// <summary> /// 儲存鍵值對 /// </summary> /// <param name="key">快取鍵</param> /// <param name="value">值</param> /// <param name="expirationSeconds">過期時間(秒),0表示永不過期</param> internal static void SetValue(string key, object value, int expirationSeconds = 0) { try { CacheData data = new CacheData(key, value); data.updateTime = DateTime.Now; data.expirationSeconds = expirationSeconds; CacheData temp; _cacheDict.TryRemove(key, out temp); _cacheDict.TryAdd(key, data); } catch (Exception ex) { LogUtil.Error(ex, "MemoryCacheUtil寫快取錯誤"); } } #endregion #region GetValue 獲取鍵值對 /// <summary> /// 獲取鍵值對 /// </summary> internal static object GetValue(string key) { try { CacheData data; if (_cacheDict.TryGetValue(key, out data)) { if (data.expirationSeconds > 0 && DateTime.Now.Subtract(data.updateTime).TotalSeconds > data.expirationSeconds) { CacheData temp; _cacheDict.TryRemove(key, out temp); return null; } return data.value; } return null; } catch (Exception ex) { LogUtil.Error(ex, "MemoryCacheUtil讀快取錯誤"); return null; } } #endregion #region Delete 刪除快取 /// <summary> /// 刪除快取 /// </summary> internal static void Delete(string key) { CacheData temp; _cacheDict.TryRemove(key, out temp); } #endregion #region DeleteAll 刪除全部快取 /// <summary> /// 刪除全部快取 /// </summary> internal static void DeleteAll() { _cacheDict.Clear(); } #endregion #region 過期快取檢測 /// <summary> /// 過期快取檢測 /// </summary> private static void _timerCheckCache_Elapsed(object sender, System.Timers.ElapsedEventArgs e) { Task.Run(() => { try { foreach (string cacheKey in _cacheDict.Keys.ToList()) { CacheData data; if (_cacheDict.TryGetValue(cacheKey, out data)) { if (data.expirationSeconds > 0 && DateTime.Now.Subtract(data.updateTime).TotalSeconds > data.expirationSeconds) { CacheData temp; string strTemp; _cacheDict.TryRemove(cacheKey, out temp); _dictLocksForReadCache.TryRemove(cacheKey, out strTemp); } } } } catch (Exception ex) { LogUtil.Error(ex, "過期快取檢測出錯"); } }); } #endregion } }
CacheData類:
/// <summary> /// 快取資料 /// </summary> [Serializable] public class CacheData { /// <summary> /// 鍵 /// </summary> public string key { get; set; } /// <summary> /// 值 /// </summary> public object value { get; set; } /// <summary> /// 快取更新時間 /// </summary> public DateTime updateTime { get; set; } /// <summary> /// 過期時間(秒),0表示永不過期 /// </summary> public int expirationSeconds { get; set; } /// <summary> /// 快取資料 /// </summary> /// <param name="key">快取鍵</param> /// <param name="value">值</param> public CacheData(string key, object value) { this.key = key; this.value = value; } }View Code
如何使用:
private void button2_Click(object sender, EventArgs e) { List<string> list = MemoryCacheUtil.TryGetValue<List<string>>("cacheKey001", () => { return QueryData(); }); } /// <summary> /// 模擬從資料庫查詢資料 /// </summary> private List<string> QueryData() { List<string> result = new List<string>(); for (int i = 0; i < 10; i++) { result.Add(i.ToString()); } return result; }View Code