js中Serializer序列化/反序列化DateTime少了8小时解决方法

作者：袖梨 2022-11-14

先看一个栗子：

JavascriptSerializer serializer = new JavascriptSerializer();
DateTime now = DateTime.Parse("2015-01-23 00:00:00");
Console.WriteLine(serializer.Deserialize(serializer.Serialize(now)));

如上图所示，反序列化后的时间比原先少了8个小时，是什么原因造成的？用ILSpy对JavascriptSerializer反编译，得到源码如下：

JavascriptSerializer.Serialize -> JavascriptSerializer.SerializeDateTime：

private static void SerializeDateTime(DateTime datetime, StringBuilder sb, JavascriptSerializer.SerializationFormat serializationFormat)
{
if (serializationFormat == JavascriptSerializer.SerializationFormat.JSON)
{
sb.Append("＼"＼＼/Date(");
sb.Append((datetime.ToUniversalTime().Ticks - JavascriptSerializer.DatetimeMinTimeTicks) / 10000L);
sb.Append(")＼＼/＼"");
return;
}
sb.Append("new Date(");
sb.Append((datetime.ToUniversalTime().Ticks - JavascriptSerializer.DatetimeMinTimeTicks) / 10000L);
sb.Append(")");
}

JavascriptSerializer.Deserialize -> JavascriptObjectDeserializer.DeserializeStringIntoDateTime：
复制内容到剪贴板程序代码
private object DeserializeStringIntoDateTime()
{
Match match = Regex.Match(this._s.ToString(), "^＼"＼＼＼＼/Date＼＼((?-?[0-9]+)(?:[a-zA-Z]|(?:＼＼+|-)[0-9]{4})?＼＼)＼＼＼＼/＼"");
string value = match.Groups["ticks"].Value;
long num;
if (long.TryParse(value, out num))
{
this._s.MoveNext(match.Length);
DateTime dateTime = new DateTime(num * 10000L + JavascriptSerializer.DatetimeMinTimeTicks, DateTimeKind.Utc);
return dateTime;
}
return this.DeserializeString();
}

JavascriptSerializer序列化时把时间转成了UTC时间，而反序列化时没转回本地时间，本地时间和UTC时间相差为8小时，这就导致了上边的问题，因此，反序列化后我们需调用ToLocalTime方法将DateTime转成本地时间：

JavascriptSerializer serializer = new JavascriptSerializer();
DateTime now = DateTime.Parse("2015-01-23 00:00:00");
Console.WriteLine(serializer.Deserialize(serializer.Serialize(now)).ToLocalTime());