Java SimpleDateFormat

External

• https://docs.oracle.com/javase/10/docs/api/java/text/SimpleDateFormat.html

Internal

• java Format
• ISO 8601

Overview

DateFormat.parse() returns a Date instance whose getTime() is always relative to GMT, regardless of the default JVM timezone or the timezone offset specified in the date string. For more details on DateFormat.parse() and timezone, see Java Time - Time Zone and DateFormat.

Thread Safety

SimpleDateFormat instances are NOT thread safe. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally. A common solution is to clone the format instance to avoid troubles.

Samples

"yy/MM/dd hh:mm:ss,SSS a"

produces:

13/01/31 01:00:00,000 PM

Excel, CSV and milliseconds

Excel understands "." so you may want to:

13/01/31 01:00:00.000 

More here: https://home.feodorov.com:9443/wiki/Wiki.jsp?page=ExcelTimeAndDateFunctions#section-ExcelTimeAndDateFunctions-HandlingMillisecondsInExcel

Hour in Day

Warning If not using AM/PM (no "a" in the format), make sure you use HH for hours (instead of hh).

According to the documentation:

• "h" - Hour in am/pm (1-12)
• "H" - Hour in a day (0-23)

Month

To parse "Sep" use "MMM".

To parse "09" use "MM".

"T" in timestamp

If "T" shows in the timestamp, it can be specified as 'T' in format.

Example: "2016-08-03T13:54:39.464-0400" is parsed with:

new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss.SSSZ");

DateFormat and Timezone

Java Time - Time Zone and DateFormat

ISO 8601 Format

new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSX")

Also see:

ISO 8601