Convert date in string format to timestamp in table definition

[Igor Kravzov]

Hi,

I have 2 dates in Json file defined like this
"addDate": "2016-05-17T02:10:44.527",
  "postDate": "2016-05-16T02:08:55",

Right now I define external table based on this file like this:
CREATE external TABLE threads_test
(url string,
 pagetype string,
 adddate string,
 postdate string,
 posttext string)
partitioned by (yyyymmdd int)
ROW FORMAT SERDE 'org.apache.hive.hcatalog.data.JsonSerDe'
location 'my location';

is it possible to define these 2 dates as timestamp?
Do I need to change date format in the file? is it possible to specify date
format in table definition?
Or I better off with string?

Thanks in advance.