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I am trying to create a time range in between two times. I am able to do it in PHP This code gives the array of times with 30 minutes interval when i supply start time , end time and interval. Below is the php script.

//timerange.php <?php /** * create_time_range * * @param mixed $start start time, e.g., 9:30am or 9:30 * @param mixed $end end time, e.g., 5:30pm or 17:30 * @param string $by 1 hour, 1 mins, 1 secs, etc. * @access public * @return void */ function create_time_range($start, $end, $by='30 mins') { $start_time = strtotime($start); $end_time = strtotime($end); $current = time(); $add_time = strtotime('+'.$by, $current); $diff = $add_time-$current; $times = array(); while ($start_time < $end_time) { $times[] = $start_time; $start_time += $diff; } $times[] = $start_time; return $times; } // create array of time ranges $times = create_time_range('9:30', '17:30', '30 mins'); // more examples // $times = create_time_range('9:30am', '5:30pm', '30 mins'); // $times = create_time_range('9:30am', '5:30pm', '1 mins'); // $times = create_time_range('9:30am', '5:30pm', '30 secs'); // and so on // format the unix timestamps foreach ($times as $key => $time) { $times[$key] = date('g:i:s', $time); } print '<pre>'. print_r($times, true).'</pre>'; /* * result * Array ( [0] => 9:30:00 [1] => 10:00:00 [2] => 10:30:00 [3] => 11:00:00 [4] => 11:30:00 [5] => 12:00:00 [6] => 12:30:00 [7] => 1:00:00 [8] => 1:30:00 [9] => 2:00:00 [10] => 2:30:00 [11] => 3:00:00 [12] => 3:30:00 [13] => 4:00:00 [14] => 4:30:00 [15] => 5:00:00 [16] => 5:30:00 ) */ ?>

I need to do the equivalent in JAVA code. I think this would be helpful to others.

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  • Java is not an acronym and should not be set in all-caps. Commented Dec 24, 2011 at 11:50
  • Use LocalTime and Duration from java.time, the modern Java date and time API and it won’t be that hard (much easier than with Calendar and the other poorly designed and long outdated date-time classes used in most of the answers). Commented Jul 14, 2019 at 19:50

4 Answers 4

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A way to do this using only java APIs is to use the Calendar class

 Date startTime = ...//start Date endTime = ../end ArrayList<String> times = new ArrayList<String>(); SimpleDateFormat sdf = new SimpleDateFormat("hh:mm:ss"); Calendar calendar = GregorianCalendar.getInstance(); calendar.setTime(startTime); while(calendar.getTime().before(endTime)) { calendar.add(Calendar.MINUTE, 30); times.add(sdf.format(calendar.getTime())); }
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6 Comments

its working, but it gives complete date and time .I need like 10:00, 10:30, 11:00 etc. can you give exact format to return time as i mentioned above.My php script gives as: [0] => 9:30:00 [1] => 10:00:00 [2] => 10:30:00 [3] => 11:00:00 [4] => 11:30:00 [5] => 12:00:00 [6] => 12:30:00
Ok I changed it to only display the time part, try it now
can you have a look at this stackoverflow.com/questions/8623058/…
i need to do it with timepicker in android.
One problem there, it does not include first value, it starts from 10:00 ,i need both inclusive means, my array should be like above php function array output
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I modified MahdeTo answer to include start time like this. I am posting whole code below.

enter code here import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; public class TimeRange { public static void main(String[] args) { // // A string of time information // String time = "9:00:00"; String time1 = "21:00:00"; // // Create an instance of SimpleDateFormat with the specified // format. // DateFormat sdf1 = new SimpleDateFormat("hh:mm:ss"); try { Date date = sdf1.parse(time); System.out.println("Date and Time: " + date); Date date1 = sdf1.parse(time1); System.out.println("Date and Time1: " + date1); ArrayList<String> times = new ArrayList<String>(); SimpleDateFormat sdf = new SimpleDateFormat("hh:mm a"); Calendar calendar = GregorianCalendar.getInstance(); calendar.setTime(date); if (calendar.getTime().before(date1)){ times.add(sdf.format(calendar.getTime())); System.out.println("Initial time: "+times); while(calendar.getTime().before(date1)) { calendar.add(Calendar.MINUTE, 30); times.add(sdf.format(calendar.getTime())); System.out.println(times); } } } catch (Exception e) { e.printStackTrace(); } } }
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2

Your best bet is probably doing this using Joda Time. It has a Duration class which you can add to a DateTime object using the .plus() method.

Take the base datetime, build your duration, cycle over it and add the datetimes into an array, just like you do (well, in fact, the code below uses a Set, since all objects will be unique).

Sample code:

public final class JodaTest { private static final DateTimeFormatter FORMAT = DateTimeFormat.forPattern("HH:mm"); public static void main(final String... args) { final DateTime start = FORMAT.parseDateTime("09:30"); final DateTime end = FORMAT.parseDateTime("17:30"); final Duration duration = Minutes.minutes(30).toStandardDuration(); final Set<DateTime> set = new LinkedHashSet<DateTime>(); DateTime d = new DateTime(start); do { set.add(d); d = d.plus(duration); } while (d.compareTo(end) <= 0); for (final DateTime dt: set) System.out.println(FORMAT.print(dt)); System.exit(0); } }
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5 Comments

i need this logic later for android app. I do know whether JODA time works for android or not.
It does. I use it in an android application, too.
check my answer to use only standard java classes
@MahdeTo which doesn't prevent my solution to work, so why vote it down?
sorry miss clicked and for some reason i can't remove it because its 2 hours ago :S
1

This is the version if you have the end time the day after.

With DateTimeFormatter

 String time = "18:30-00:30"; String startTime = time.split("-")[0]; String endTime = time.split("-")[1]; ArrayList<String> times = new ArrayList<>(); LocalDate today = LocalDate.now(); DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("dd/MM/yyyy-HH:mm"); LocalDateTime localT0 = LocalDateTime.parse(startTime).atDate(today); LocalDateTime localT1 = LocalDateTime.parse(endTime).atDate(today); if (localT0.isAfter(localT1)){ localT1 = localT1.plusDays(1); } while (localT0.isBefore(localT1)){ times.add(localT0.format(dateTimeFormatter)); localT0 = localT0.plusMinutes(30); } System.out.println(times.toString());

With SimpleDateFormat

 String time = "18:30-00:30"; String startTime = time.split("-")[0]; String endTime = time.split("-")[1]; ArrayList<String> times = new ArrayList<>(); Calendar calendar = Calendar.getInstance(); Calendar calendar1 = Calendar.getInstance(); String day = new SimpleDateFormat("dd/MM/yyyy").format(calendar.getTime()); SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy-HH:mm"); Date time1 = null; Date time2 = null; try { time1 = sdf.parse(day + "-" + startTime); time2 = sdf.parse(day + "-" + endTime); } catch (ParseException e) { e.printStackTrace(); } calendar.setTime(time1); calendar1.setTime(time2); if (calendar.getTime().after(calendar1.getTime())){ calendar1.add(Calendar.DATE, 1); } while(calendar.getTime().before(calendar1.getTime())) { times.add(sdf.format(calendar.getTime())); calendar.add(Calendar.MINUTE, 30); } System.out.println(times.toString());
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4 Comments

Please don’t teach the young ones to use the long outdated and notoriously troublesome SimpleDateFormat class. At least not as the first option. And not without any reservation. Today we have so much better in java.time, the modern Java date and time API, and its DateTimeFormatter.
@OleV.V. You are right. Check if there is a simplest solution
There are other ways, but possibly not simpler. I might have tried to get through without using LocalDateTime, but it would have involved some trickery and might have ended up harder to read. I have upvoted your answer.
Two suggestions, though: (1) Keep LocalTime or LocalDateTime objects in your list, not strings. (2) Don’t use the formatter. Declare LocalDate today = LocalDate.now(); and then set LocalDateTime localT0 = LocalTime.parse(startTime).atDate(today); and similarly for localT1.

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