初始化CRICS

Common/MemoryCacheUtil.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.Caching;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Common
+{
+    public static class MemoryCacheUtil
+    {
+        private static readonly Object _locker = new object(), _locker2 = new object();
+
+        /// <summary>
+        /// 取缓存项，如果不存在则返回空
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="key"></param>
+        /// <returns></returns>
+        public static T GetCacheItem<T>(String key)
+        {
+            try
+            {
+                return (T)MemoryCache.Default[key];
+            }
+            catch
+            {
+                return default(T);
+            }
+        }
+
+        /// <summary>
+        /// 是否包含指定键的缓存项
+        /// </summary>
+        /// <param name="key"></param>
+        /// <returns></returns>
+        public static bool Contains(string key)
+        {
+            return MemoryCache.Default.Contains(key);
+        }
+
+        /// <summary>
+        /// 取缓存项,如果不存在则新增缓存项
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="key"></param>
+        /// <param name="cachePopulate"></param>
+        /// <param name="slidingExpiration"></param>
+        /// <param name="absoluteExpiration"></param>
+        /// <returns></returns>
+        public static T GetOrAddCacheItem<T>(String key, Func<T> cachePopulate, TimeSpan? slidingExpiration = null, DateTime? absoluteExpiration = null)
+        {
+            if (String.IsNullOrWhiteSpace(key)) throw new ArgumentException("Invalid cache key");
+            if (cachePopulate == null) throw new ArgumentNullException("cachePopulate");
+            if (slidingExpiration == null && absoluteExpiration == null) throw new ArgumentException("Either a sliding expiration or absolute must be provided");
+
+            if (MemoryCache.Default[key] == null)
+            {
+                lock (_locker)
+                {
+                    if (MemoryCache.Default[key] == null)
+                    {
+                        T cacheValue = cachePopulate();
+                        if (!typeof(T).IsValueType && ((object)cacheValue) == null) //如果是引用类型且为NULL则不存缓存
+                        {
+                            return cacheValue;
+                        }
+
+                        var item = new CacheItem(key, cacheValue);
+                        var policy = CreatePolicy(slidingExpiration, absoluteExpiration);
+
+                        MemoryCache.Default.Add(item, policy);
+                    }
+                }
+            }
+
+            return (T)MemoryCache.Default[key];
+        }
+
+        /// <summary>
+        /// 取缓存项,如果不存在则新增缓存项
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="key"></param>
+        /// <param name="cachePopulate"></param>
+        /// <param name="dependencyFilePath"></param>
+        /// <returns></returns>
+        public static T GetOrAddCacheItem<T>(String key, Func<T> cachePopulate, string dependencyFilePath)
+        {
+            if (String.IsNullOrWhiteSpace(key)) throw new ArgumentException("Invalid cache key");
+            if (cachePopulate == null) throw new ArgumentNullException("cachePopulate");
+
+            if (MemoryCache.Default[key] == null)
+            {
+                lock (_locker2)
+                {
+                    if (MemoryCache.Default[key] == null)
+                    {
+                        T cacheValue = cachePopulate();
+                        if (!typeof(T).IsValueType && ((object)cacheValue) == null) //如果是引用类型且为NULL则不存缓存
+                        {
+                            return cacheValue;
+                        }
+
+                        var item = new CacheItem(key, cacheValue);
+                        var policy = CreatePolicy(dependencyFilePath);
+
+                        MemoryCache.Default.Add(item, policy);
+                    }
+                }
+            }
+
+            return (T)MemoryCache.Default[key];
+        }
+
+        /// <summary>
+        /// 移除指定键的缓存项
+        /// </summary>
+        /// <param name="key"></param>
+        public static void RemoveCacheItem(string key)
+        {
+            try
+            {
+                MemoryCache.Default.Remove(key);
+            }
+            catch
+            { }
+        }
+
+        private static CacheItemPolicy CreatePolicy(TimeSpan? slidingExpiration, DateTime? absoluteExpiration)
+        {
+            var policy = new CacheItemPolicy();
+
+            if (absoluteExpiration.HasValue)
+            {
+                policy.AbsoluteExpiration = absoluteExpiration.Value;
+            }
+            else if (slidingExpiration.HasValue)
+            {
+                policy.SlidingExpiration = slidingExpiration.Value;
+            }
+
+            policy.Priority = CacheItemPriority.Default;
+
+            return policy;
+        }
+
+        private static CacheItemPolicy CreatePolicy(string filePath)
+        {
+            CacheItemPolicy policy = new CacheItemPolicy();
+            policy.ChangeMonitors.Add(new HostFileChangeMonitor(new List<string>() { filePath }));
+            policy.Priority = CacheItemPriority.Default;
+            return policy;
+        }
+    }
+}