diff --git a/WebSiteCode/Cmdjy/Cmdjy/Bll/Cache.cs b/WebSiteCode/Cmdjy/Cmdjy/Bll/Cache.cs
index b77b64e..a8ddbdc 100644
--- a/WebSiteCode/Cmdjy/Cmdjy/Bll/Cache.cs
+++ b/WebSiteCode/Cmdjy/Cmdjy/Bll/Cache.cs
@@ -16,7 +16,7 @@ namespace Cmdjy.Bll
         /// <typeparam name="T">数据类型</typeparam>
         /// <param name="key">保存的key</param>
         /// <returns>缓存的数据</returns>
-        T GetData<T>(string key);
+        T GetData<T>(string key) where T : class;
         /// <summary>
         /// 缓存数据,缓存时间默认
         /// </summary>
@@ -55,8 +55,8 @@ namespace Cmdjy.Bll
             this.Database = this.Database ?? Connection.GetDatabase(0);
         }
 
-        public T GetData<T>(string key) {
-            if(!Usable) return default(T);
+        public T GetData<T>(string key) where T : class {
+            if(!Usable) return null;
             return fromJson<T>(Database.StringGet(key));
         }