缓存主要是为了提高数据的读取速度，在一些处理比较慢，时间要求高的地方，试用缓存还是很有必要的
using System; using System.Collections.Generic; using System.Linq; using System.Runtime.Caching; using System.Text; using System.Threading.Tasks; namespace SuperMaterial.Common { /// <summary> /// 缓存帮助类 /// </summary> public class CacheHelper { /// <summary> /// 默认缓存 /// </summary> private static CacheHelper Default { get { return new CacheHelper(); } } /// <summary> /// 缓存初始化 /// </summary> private MemoryCache cache = MemoryCache.Default; /// <summary> /// 锁 /// </summary> private object locker = new object(); /// <summary> /// 构造器 /// </summary> private CacheHelper() { //CacheItemPolicy policy = new CacheItemPolicy(); //创建缓存项策略 ////过期时间设置,以下两种只能设置一种 //policy.AbsoluteExpiration = new DateTimeOffset(DateTime.Now.AddMinutes(5)); //设定某个时间过后将逐出缓存 //policy.SlidingExpiration = new TimeSpan(0, 0, 10); //设定某个时间段内未被访问将逐出缓存 ////逐出通知,以下两种只能设置一种 //policy.UpdateCallback = arguments => { Console.WriteLine("即将逐出缓存" + arguments.Key); }; } /// <summary> /// 从缓存中获取对象 /// </summary> /// <typeparam name="T">对象类型</typeparam> /// <param name="key">键</param> /// <returns>缓存对象</returns> public static T Get<T>(string key) { return Default.GetFromCache<T>(key); } /// <summary> /// 从缓存中获取对象 /// </summary> /// <typeparam name="T">对象类型</typeparam> /// <param name="key">键</param> /// <returns>缓存对象</returns> private T GetFromCache<T>(string key) { lock (locker) { if (cache.Contains(key)) { return (T)cache[key]; } return default(T); } } /// <summary> /// 添加泛型缓存 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="key"></param> /// <param name="value"></param> /// <param name="seconds">默认缓存180s</param> public static void Set<T>(string key, T value, double seconds = 180) { Default.SetToCache<T>(key, value, seconds); } /// <summary> /// 泛型缓存 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="key"></param> /// <param name="value"></param> /// <param name="seconds">默认缓存180s</param> private void SetToCache<T>(string key, T value, double seconds) { CacheItemPolicy policy = new CacheItemPolicy() { AbsoluteExpiration = DateTime.Now.AddSeconds(seconds) }; lock (locker) { cache.Set(key, value, policy); } } /// <summary> /// 获取键的集合 /// </summary> /// <returns>键的集合</returns> public static ICollection<string> Keys() { return Default.GetCacheKeys(); } /// <summary> /// 获取键的集合 /// </summary> /// <returns>键的集合</returns> private ICollection<string> GetCacheKeys() { lock (locker) { IEnumerable<KeyValuePair<string, object>> items = cache.AsEnumerable(); return items.Select(m => m.Key).ToList(); } } /// <summary> /// 判断缓存中是否有此对象 /// </summary> /// <param name="key">键</param> /// <returns>是否存在</returns> public static bool Contain(string key) { return Default.ContainKey(key); } /// <summary> /// 判断缓存中是否有此对象 /// </summary> /// <param name="key">键</param> /// <returns>是否存在</returns> private bool ContainKey(string key) { lock (locker) { return cache.Contains(key); } } /// <summary> /// 数据对象从缓存对象中移除 /// </summary> /// <param name="key">键</param> public static bool Remove(string key) { return Default.RemoveFromCache(key); } /// <summary> /// 数据对象从缓存对象中移除 /// </summary> /// <param name="key">键</param> private bool RemoveFromCache(string key) { lock (locker) { if (cache.Contains(key)) { cache.Remove(key); return true; } return false; } } /// <summary> /// 清除实例 /// </summary> public static void Clear() { Default.ClearCache(); } /// <summary> /// 清除实例 /// </summary> private void ClearCache() { lock (locker) { cache.ToList().ForEach(m => cache.Remove(m.Key)); } } /// <summary> /// 获取缓存对象集合 /// </summary> /// <typeparam name="T">缓存对象类型</typeparam> /// <returns>缓存对象集合</returns> public static ICollection<T> Values<T>() { return Default.GetValues<T>(); } /// <summary> /// 获取缓存对象集合 /// </summary> /// <typeparam name="T">缓存对象类型</typeparam> /// <returns>缓存对象集合</returns> private ICollection<T> GetValues<T>() { lock (locker) { IEnumerable<KeyValuePair<string, object>> items = cache.AsEnumerable(); return items.Select(m => (T)m.Value).ToList(); } } /// <summary> /// 获取缓存尺寸 /// </summary> /// <returns>缓存尺寸</returns> public static long Size() { return Default.GetCacheSize(); } /// <summary> /// 获取缓存尺寸 /// </summary> /// <returns>缓存尺寸</returns> private long GetCacheSize() { lock (locker) { return cache.GetCount(); } } } }
使用
1新增缓存 CacheHelper.Set<T>(CacheKey, CacheValue, CacheTime); 2读取缓存 if(CacheHelper.Contain(CacheKey)) { CacheValue=CacheHelper.Get<T>(CacheKey) } 3重新更新缓存 if (CacheHelper.Contain(CacheKey)) { CacheHelper.Remove(CacheKey); } CacheHelper.Set<T>(CacheKey, CacheValue, CacheTime);