Question

What is the most efficient method of converting an int val to its string counterpart in this format – “HH:MM:SS”

10 becomes 00:00:10
70 becomes 00:01:10
3610 becomes 01:00:10

I need this to be JDK1.4 compliant.

What I’ve come up with is a series of if statements and then constructing a string based on the current int val. This is not very efficient. Is there a better way?

Answer 1

Instead of a heap of code, how about just one line?

String time = new SimpleDateFormat("HH:mm:ss")  
    {{setTimeZone(TimeZone.getTimeZone("UTC"));}}.format(new Date(3610 * 1000)); // "01:00:10"

p.s. I never fails to amaze me just how much code some people write to do the simplest of things

The timezone is set to UTC, because SimpleDateFormat uses your locale to format the date. For example my timezone is GMT+10 and if I format new Date(0), the time part is “10:00:00”.

For those who don’t recognise that odd syntax where the timezone is being set, it’s an anonymous class with an “instance block”, which gets executed on construction, after the constructor has finished.