升级自定义交易组件常用商品接口，spu接口，品牌接口，订单接口，物流接口。

CoreCms.Net.Utility/Helper/TimeHelper.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CoreCms.Net.Utility.Helper
+{
+    public class TimeHelper
+    {
+        /// <summary>
+        ///  时间戳转本地时间-时间戳精确到秒
+        /// </summary> 
+        public static DateTime ToLocalTimeDateBySeconds(long unix)
+        {
+            var dto = DateTimeOffset.FromUnixTimeSeconds(unix);
+            return dto.ToLocalTime().DateTime;
+        }
+
+        /// <summary>
+        ///  时间转时间戳Unix-时间戳精确到秒
+        /// </summary> 
+        public static long ToUnixTimestampBySeconds(DateTime dt)
+        {
+            DateTimeOffset dto = new DateTimeOffset(dt);
+            return dto.ToUnixTimeSeconds();
+        }
+
+        /// <summary>
+        ///  时间戳转本地时间-时间戳精确到毫秒
+        /// </summary> 
+        public static DateTime ToLocalTimeDateByMilliseconds(long unix)
+        {
+            var dto = DateTimeOffset.FromUnixTimeMilliseconds(unix);
+            return dto.ToLocalTime().DateTime;
+        }
+
+        /// <summary>
+        ///  时间转时间戳Unix-时间戳精确到毫秒
+        /// </summary> 
+        public static long ToUnixTimestampByMilliseconds(DateTime dt)
+        {
+            DateTimeOffset dto = new DateTimeOffset(dt);
+            return dto.ToUnixTimeMilliseconds();
+        }
+
+    }
+}