Postgres has two different timestamp data types: timestamp with time zone, short name: timestamptz timestamp without time zone, short name: timestamp timestamptz is the preferred type in the date/time family, literally. It has typispreferred set in pg_type, which can be relevant: Generating time series between two dates in PostgreSQL Internal storage and epoch Internally, timestamps … Read more
Background JavaScript’s Date object tracks time in UTC internally, but typically accepts input and produces output in the local time of the computer it’s running on. It has very few facilities for working with time in other time zones. The internal representation of a Date object is a single number, representing the number of milliseconds … Read more
Summary of answers and other data: (please add yours) Do: Whenever you are referring to an exact moment in time, persist the time according to a unified standard that is not affected by daylight savings. (GMT and UTC are equivalent with this regard, but it is preferred to use the term UTC. Notice that UTC … Read more
Calendar calendar = Calendar.getInstance(); Calendar LATime = new GregorianCalendar(TimeZone.getTimeZone(“America/Los_Angeles”)); LATime.setTimeInMillis(calendar.getTimeInMillis()); int year = LATime.get(Calendar.YEAR); int month = LATime.get(Calendar.MONTH); int date = LATime.get(Calendar.DATE); int dayOfWeek = calender.get(Calendar.DAY_OF_WEEK); Try it out
The only place where you can get such information reliably is the client machine. Javascript would be the way to go. Geo-location will not work when behind a proxy and is generally not very reliable (in my experience).
It’s a time zone change on December 31st in Shanghai. See this page for details of 1927 in Shanghai. Basically at midnight at the end of 1927, the clocks went back 5 minutes and 52 seconds. So “1927-12-31 23:54:08” actually happened twice, and it looks like Java is parsing it as the later possible instant … Read more