How to calculate "time ago" in Java?
In Ruby on Rails, there is a feature that allows you to take any Date and print out how "long ago" it was.
For example:
8 minutes ago
8 hours ago
8 days ago
8 months ago
8 years ago
Is there an easy way to do this in Java?
Solution 1:
Take a look at the PrettyTime library.
It's quite simple to use:
import org.ocpsoft.prettytime.PrettyTime;
PrettyTime p = new PrettyTime();
System.out.println(p.format(new Date()));
// prints "moments ago"
You can also pass in a locale for internationalized messages:
PrettyTime p = new PrettyTime(new Locale("fr"));
System.out.println(p.format(new Date()));
// prints "à l'instant"
As noted in the comments, Android has this functionality built into the android.text.format.DateUtils class.
Solution 2:
Have you considered the TimeUnit enum? It can be pretty useful for this kind of thing
try {
SimpleDateFormat format = new SimpleDateFormat("dd/MM/yyyy");
Date past = format.parse("01/10/2010");
Date now = new Date();
System.out.println(TimeUnit.MILLISECONDS.toMillis(now.getTime() - past.getTime()) + " milliseconds ago");
System.out.println(TimeUnit.MILLISECONDS.toMinutes(now.getTime() - past.getTime()) + " minutes ago");
System.out.println(TimeUnit.MILLISECONDS.toHours(now.getTime() - past.getTime()) + " hours ago");
System.out.println(TimeUnit.MILLISECONDS.toDays(now.getTime() - past.getTime()) + " days ago");
}
catch (Exception j){
j.printStackTrace();
}
Solution 3:
I take RealHowTo and Ben J answers and make my own version:
public class TimeAgo {
public static final List<Long> times = Arrays.asList(
TimeUnit.DAYS.toMillis(365),
TimeUnit.DAYS.toMillis(30),
TimeUnit.DAYS.toMillis(1),
TimeUnit.HOURS.toMillis(1),
TimeUnit.MINUTES.toMillis(1),
TimeUnit.SECONDS.toMillis(1) );
public static final List<String> timesString = Arrays.asList("year","month","day","hour","minute","second");
public static String toDuration(long duration) {
StringBuffer res = new StringBuffer();
for(int i=0;i< TimeAgo.times.size(); i++) {
Long current = TimeAgo.times.get(i);
long temp = duration/current;
if(temp>0) {
res.append(temp).append(" ").append( TimeAgo.timesString.get(i) ).append(temp != 1 ? "s" : "").append(" ago");
break;
}
}
if("".equals(res.toString()))
return "0 seconds ago";
else
return res.toString();
}
public static void main(String args[]) {
System.out.println(toDuration(123));
System.out.println(toDuration(1230));
System.out.println(toDuration(12300));
System.out.println(toDuration(123000));
System.out.println(toDuration(1230000));
System.out.println(toDuration(12300000));
System.out.println(toDuration(123000000));
System.out.println(toDuration(1230000000));
System.out.println(toDuration(12300000000L));
System.out.println(toDuration(123000000000L));
}}
which will print the following
0 second ago
1 second ago
12 seconds ago
2 minutes ago
20 minutes ago
3 hours ago
1 day ago
14 days ago
4 months ago
3 years ago
Solution 4:
public class TimeUtils {
public final static long ONE_SECOND = 1000;
public final static long SECONDS = 60;
public final static long ONE_MINUTE = ONE_SECOND * 60;
public final static long MINUTES = 60;
public final static long ONE_HOUR = ONE_MINUTE * 60;
public final static long HOURS = 24;
public final static long ONE_DAY = ONE_HOUR * 24;
private TimeUtils() {
}
/**
* converts time (in milliseconds) to human-readable format
* "<w> days, <x> hours, <y> minutes and (z) seconds"
*/
public static String millisToLongDHMS(long duration) {
StringBuffer res = new StringBuffer();
long temp = 0;
if (duration >= ONE_SECOND) {
temp = duration / ONE_DAY;
if (temp > 0) {
duration -= temp * ONE_DAY;
res.append(temp).append(" day").append(temp > 1 ? "s" : "")
.append(duration >= ONE_MINUTE ? ", " : "");
}
temp = duration / ONE_HOUR;
if (temp > 0) {
duration -= temp * ONE_HOUR;
res.append(temp).append(" hour").append(temp > 1 ? "s" : "")
.append(duration >= ONE_MINUTE ? ", " : "");
}
temp = duration / ONE_MINUTE;
if (temp > 0) {
duration -= temp * ONE_MINUTE;
res.append(temp).append(" minute").append(temp > 1 ? "s" : "");
}
if (!res.toString().equals("") && duration >= ONE_SECOND) {
res.append(" and ");
}
temp = duration / ONE_SECOND;
if (temp > 0) {
res.append(temp).append(" second").append(temp > 1 ? "s" : "");
}
return res.toString();
} else {
return "0 second";
}
}
public static void main(String args[]) {
System.out.println(millisToLongDHMS(123));
System.out.println(millisToLongDHMS((5 * ONE_SECOND) + 123));
System.out.println(millisToLongDHMS(ONE_DAY + ONE_HOUR));
System.out.println(millisToLongDHMS(ONE_DAY + 2 * ONE_SECOND));
System.out.println(millisToLongDHMS(ONE_DAY + ONE_HOUR + (2 * ONE_MINUTE)));
System.out.println(millisToLongDHMS((4 * ONE_DAY) + (3 * ONE_HOUR)
+ (2 * ONE_MINUTE) + ONE_SECOND));
System.out.println(millisToLongDHMS((5 * ONE_DAY) + (4 * ONE_HOUR)
+ ONE_MINUTE + (23 * ONE_SECOND) + 123));
System.out.println(millisToLongDHMS(42 * ONE_DAY));
/*
output :
0 second
5 seconds
1 day, 1 hour
1 day and 2 seconds
1 day, 1 hour, 2 minutes
4 days, 3 hours, 2 minutes and 1 second
5 days, 4 hours, 1 minute and 23 seconds
42 days
*/
}
}
more @Format a duration in milliseconds into a human-readable format
Solution 5:
This is based on RealHowTo's answer so if you like it, give him/her some love too.
This cleaned up version allows you to specify the range of time you might be interested in.
It also handles the " and " part a little differently. I often find when joining strings with a delimiter it's ofter easier to skip the complicated logic and just delete the last delimiter when you're done.
import java.util.concurrent.TimeUnit;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
public class TimeUtils {
/**
* Converts time to a human readable format within the specified range
*
* @param duration the time in milliseconds to be converted
* @param max the highest time unit of interest
* @param min the lowest time unit of interest
*/
public static String formatMillis(long duration, TimeUnit max, TimeUnit min) {
StringBuilder res = new StringBuilder();
TimeUnit current = max;
while (duration > 0) {
long temp = current.convert(duration, MILLISECONDS);
if (temp > 0) {
duration -= current.toMillis(temp);
res.append(temp).append(" ").append(current.name().toLowerCase());
if (temp < 2) res.deleteCharAt(res.length() - 1);
res.append(", ");
}
if (current == min) break;
current = TimeUnit.values()[current.ordinal() - 1];
}
// clean up our formatting....
// we never got a hit, the time is lower than we care about
if (res.lastIndexOf(", ") < 0) return "0 " + min.name().toLowerCase();
// yank trailing ", "
res.deleteCharAt(res.length() - 2);
// convert last ", " to " and"
int i = res.lastIndexOf(", ");
if (i > 0) {
res.deleteCharAt(i);
res.insert(i, " and");
}
return res.toString();
}
}
Little code to give it a whirl:
import static java.util.concurrent.TimeUnit.*;
public class Main {
public static void main(String args[]) {
long[] durations = new long[]{
123,
SECONDS.toMillis(5) + 123,
DAYS.toMillis(1) + HOURS.toMillis(1),
DAYS.toMillis(1) + SECONDS.toMillis(2),
DAYS.toMillis(1) + HOURS.toMillis(1) + MINUTES.toMillis(2),
DAYS.toMillis(4) + HOURS.toMillis(3) + MINUTES.toMillis(2) + SECONDS.toMillis(1),
DAYS.toMillis(5) + HOURS.toMillis(4) + MINUTES.toMillis(1) + SECONDS.toMillis(23) + 123,
DAYS.toMillis(42)
};
for (long duration : durations) {
System.out.println(TimeUtils.formatMillis(duration, DAYS, SECONDS));
}
System.out.println("\nAgain in only hours and minutes\n");
for (long duration : durations) {
System.out.println(TimeUtils.formatMillis(duration, HOURS, MINUTES));
}
}
}
Which will output the following:
0 seconds
5 seconds
1 day and 1 hour
1 day and 2 seconds
1 day, 1 hour and 2 minutes
4 days, 3 hours, 2 minutes and 1 second
5 days, 4 hours, 1 minute and 23 seconds
42 days
Again in only hours and minutes
0 minutes
0 minutes
25 hours
24 hours
25 hours and 2 minutes
99 hours and 2 minutes
124 hours and 1 minute
1008 hours
And in case anyone ever needs it, here's a class that will convert any string like the above back into milliseconds. It's pretty useful for allowing people to specify timeouts of various things in readable text.