<p>I'm conducting experiments regarding e-mail spam. One of these experiments require sending mail thru Tor. Since I'm using Python and smtplib for my experiments, I'm looking for a way to use the Tor proxy (or other method) to perform that mail sending.
Ideas how this can be done?</p>

If you're using a version of Java prior to 8... you can use
Joda Time
and
```
PeriodFormatter
```
. If you've really got a duration (i.e. an elapsed amount of time, with no reference to a calendar system) then you should probably be using
```
Duration
```
for the most part - you can then call
```
toPeriod
```
(specifying whatever
```
PeriodType
```
you want to reflect whether 25 hours becomes 1 day and 1 hour or not, etc) to get a
```
Period
```
which you can format.
If you're using Java 8 or later: I'd normally suggest using
```
java.time.Duration
```
to represent the duration. You can then call
```
getSeconds()
```
or the like to obtain an integer for standard string formatting as per bobince's answer if you need to - although you should be careful of the situation where the duration is negative, as you probably want a
single
negative sign in the output string. So something like:
```
```
public static String formatDuration(Duration duration) {
    long seconds = duration.getSeconds();
    long absSeconds = Math.abs(seconds);
    String positive = String.format(
        "%d:%02d:%02d",
        absSeconds / 3600,
        (absSeconds % 3600) / 60,
        absSeconds % 60);
    return seconds < 0 ? "-" + positive : positive;
}
```
```
Formatting this way is
reasonably
simple, if annoyingly manual. For
parsing
it becomes a harder matter in general... You could still use Joda Time even with Java 8 if you want to, of course.