Human readable and parsable date format in Java.

Question

I want to save a Date object to a readable string (for example 22/10/2009 21:13:14) that is also parsable back to a Date object.

I have tried many things and the best I could find was to use DateFormater for parsing and formating but it has a setback. When you format a date you lose seconds information. I tried to find if there is an option to format it and display the seconds (even better would be to the millisecond level since that's the resolution the Date object allows you to have) but I came up short.

Any ideas?

Answer 1

Take a look at java.text.SimpleDateFormat

SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss.SSS");
Date dt = new Date();
String S = sdf.format(dt); // formats to 09/23/2009 13:53:28.238
Date dt2 = sdf.parse(S); // parses back

Answer 2

SimpleDateFormat can format and parse a date based on a very simple pattern system that include second and even milliseconds.

Answer 3

A little off-topic, but I always feel the need to remind people that DateFormat and SimpleDateFormat are not thread safe! The Sun documentation clearly states this, but I keep finding code out in the wild where people stick a SimpleDateFormat in a static ...

Answer 4

Also probably off-topic, but for real readability there is an evolving sourceforge project called jFuzzyDate, this project aims to format dates to strings like "yesterday" or "in 5 weeks" which is much more information to most people. The uri is http://jfuzzydate.sourceforge.net/