This question already has answers here:
Number of days between two dates in Joda-Time
(9 answers)
Closed 9 years ago.
I know this isn't "the way it's supposed to work", but still: If you have two DateTime objects, what's a good way to subtract them? Convert them to Date objects?
DateTime start = new DateTime();
System.out.println(start + " - doing some stuff");
// do stuff
DateTime end = new DateTime();
Period diff = // end - start ???
System.out.println(end + " - doing some stuff took diff seconds");
Period has a constructor that takes two ReadableInstant instances:
Period diff = new Period(start, end);
(ReadableInstant is an interface implemented by DateTime, as well as other classes.)
From your example you seem to want the difference in seconds so this should help :
Seconds diff = Seconds.secondsBetween(start, end);
Does this help? http://joda-time.sourceforge.net/key_period.html
It shows the below example
DateTime start = new DateTime(2004, 12, 25, 0, 0, 0, 0);
DateTime end = new DateTime(2006, 1, 1, 0, 0, 0, 0);
// period of 1 year and 7 days
Period period = new Period(start, end);
// calc will equal end
DateTime calc = start.plus(period);
// able to calculate whole days between two dates easily
Days days = Days.daysBetween(start, end);
Depends in which precision you want to get. You should check the org.joda.time package and check for the Helper classes such as Hours, Days, etc.
I think you can create a Period using this constructor which takes two DateTime objects.
Related
How to calculate the number of "full" months between two dates with joda time, dropping incomplete months?
For example, I have 2 dates
LocalDate from = new LocalDate (2018, 9, 10);
LocalDate to = new LocalDate (2018, 11, 15);
Between these dates there is one "full" month - October from 1 to 31.
So I want to get is the number "1" by dropping the "incomplete" months - September and November
I need something like this
System.out.println(Months.monthsBetween(from, to).getMonths()); // returns 2
System.out.println(Months.**completed**MonthsBetween(from, to).getMonths()); // returns 1
UPD 1.
I could achieve what I want as follows:
LocalDate from = new LocalDate (2018, 9, 10);
LocalDate to = new LocalDate (2018, 11, 15);
if (to.getDayOfMonth() != 1)
from = from.plusMonths(1).withDayOfMonth(1);
if (to.getDayOfMonth() != 1)
to = to.withDayOfMonth(1);
System.out.println(Months.monthsBetween(from, to).getMonths());
but maybe there is an out of the box method?
Wouldn't this means that you simply want to remove one month from each interval and do a difference between them?
LocalDate fromMinusOne = from.minus(Months.ONE);
LocalDate toMinusOne = to.minus(Months.ONE);
System.out.println(Months.monthsBetween(fromMinusOne, toMinusOne).getMonths());
Joda Time provides methods to extract days, months and years between two dates. Create two instances of you date.
DateTime startDate = DateTime.parse("1970-01-01", DateTimeFormat.forPattern("yyyy-MM-dd"))
DateTime endDate = DateTime.parse("2015-02-25", DateTimeFormat.forPattern("yyyy-MM-dd"))
You can create your date instances in LocalDate as well instead of DateTime.
Now, complete months between above two dates can be found easily with,
int months = Months.monthsBetween(startDate.withDayOfMonth(1), endDate.withDayOfMonth(1)).getMonths()
For days,
int days = Days.daysBetween(startDate, endDate).getDays()
Difference between two dates in months
For years,
int years = Years.yearsBetween(startDate, endDate).getYears();
This question already has answers here:
Number of days between two dates in Joda-Time
(9 answers)
Closed 7 years ago.
I need to get the difference in months between two dates, I'm using Joda Time, the problem is this:
DateTime date1 = new DateTime().withDate(2015, 2, 1);
DateTime date2 = new DateTime().withDate(2015, 1, 1);
Months m = Months.monthsBetween(date1, date2);
int monthDif = m.getMonths();//this return 0
it returns 0 because there is no month in the middle of the two dates, I need to return the difference in months not a few months in between, and add 1 would be problematic when the dates are the same.
Changing the first date to 2015-02-02, Joda correctly returns 1 month:
DateTime date1 = new DateTime().withDate(2015, 2, 2);
DateTime date2 = new DateTime().withDate(2015, 1, 1);
System.out.println(Months.monthsBetween(date2, date1).getMonths());
// Returns 1.
So my guess is that because you didn't provide a time portion, Joda cannot be precise about exactly which point in time of 2015-01-01 date2 refers to. You might have as well referred to 23:59:59, in which case a full month wouldn't have elapsed yet, technically.
If you provide a zero time portion explicitly, it works as you initially expected:
DateTime date1 = new DateTime().withDate(2015, 2, 1).withTime(0, 0, 0, 0);
DateTime date2 = new DateTime().withDate(2015, 1, 1).withTime(0, 0, 0, 0);
System.out.println(Months.monthsBetween(date2, date1).getMonths());
// Returns 1.
Therefore, I recommend you specify a 00:00:00 time portion in each date explicitly.
While other answers are correct they still mask the real problem.
it returns 0 because there is no month in the middle of the two dates
No. It returns 0 because there is time part of DateTime object. You creating two istances of DateTime filled with current moment in time (with hours, minutes, seconds and milliseconds) and then modify just date part. There is no reasons to do it if you want to compare just two dates. use LocalDate instead.
LocalDate date1 = new LocalDate(2015, 2, 1);
LocalDate date2 = new LocalDate(2015, 1, 1);
Months m = Months.monthsBetween(date1, date2);
int monthDif = Math.abs(m.getMonths());//this return 1
Also need to pay attention to the fact that despite the fact that Months docs say nothing about it, Month can contain negative value if first date is after second date. So we need to use Math.abs to really count the number of months between two dates.
The docs say:
Creates a Months representing the number of whole months between the two specified partial datetimes.
But it isn't true. It really calculates the difference in months. Not the number of months.
The way this is calculated depends on the business logic that is to be used. Each month varies in length. One option would be to, in the monthsBetween() function, get the start of the month for both date1 and date2, and compare that.
Something like:
DateTime firstOfMonthDate1 = new DateTime(date1.getYear(), date1.getMonthOfYear(), 1, 0, 0);
DateTime firstOfMonthDate2 = new DateTime(date2.getYear(), date2.getMonthOfYear(), 1, 0, 0);
Months m = Months.monthsBetween(firstOfMonthDate1, firstOfMonthDate2)
Example:
LocalTime time1 = LocalTime.of(12, 30);
LocalTime time2 = LocalTime.of(8, 30);
time1 + time2 // Doesn't work.
time1.plus(time2) // Doesn't work.
I want to get the sum of the two times (12:30 + 8:30 = 21:00) in the format of (hours:minutes).
Any other suggestions?
You are trying to add two LocalTime variables. This is wrong as a concept. Your time2 should not be a LocalTime, it should be a Duration. A duration added to a time gives you another time. A time subtracted from a time gives you a duration. It is all nice and logical. Adding two times together is not.
It is possible with some hacking to convert your time to a duration, but I would strongly advise against that. Instead, restructure your code so that time2 is a Duration in the first place.
You can do the following...
LocalTime t1 = LocalTime.of(9, 0); // 09:00
LocalTime t2 = LocalTime.of(2, 30); // 02:30
LocalTime total = t1.plusHours(t2.getHour())
.plusMinutes(t2.getMinute()); // 11:30
The answer of Mike Nakis does not true.
The above sentence of mine doesn't true. I have checked and only Java 8 has LocalTime.of so Mike Nakis's answer is perfectly true. Please see his answer.
[This section still keep. in case LocalTime in joda library ]
I will explain:
A duration in Joda-Time represents a duration of time measured in milliseconds. The duration is often obtained from an interval. i.e. we
can subtract start from end of an interval to derive a duration.
A period in Joda-Time represents a period of time defined in terms of fields, for example, 3 years 5 months 2 days and 7 hours. This
differs from a duration in that it is inexact in terms of
milliseconds. A period can only be resolved to an exact number of
milliseconds by specifying the instant (including chronology and time
zone) it is relative to. e.g. consider the period of 1 year, if we add
this to January 1st we will always arrive at the next January 1st but
the duration will depend on whether the intervening year is a leap
year or not.
LocalTime is an immutable time class representing a time without a time zone. So, base on above definition, period is suitable for you adding time to LocalTime. In fact, API has proved this:
LocalTime localTime = new LocalTime(10, 30);
Duration d = new Duration(1, 0);
Period p = new Period(1, 0);
LocalTime newLocalTime = localTime.plus(d); // COMPILE ERROR
LocalTime newLocalTime = localTime.plus(p); // SUCCESS
you can use the method sum()
LocalTime time1 = LocalTime.of(12, 30);
LocalTime time2 = LocalTime.of(8, 30);
Integer hour1 = time1.getHour();
Integer hour2 = time2.getHour();
Integer minute1 = time1.getMinute();
Integer minute2 = time2.getMinute();
Integer first = Integer.sum(hour1,hour2);
Integer second = Integer.sum(minute1,minute2);
System.out.println("The time is "+ first + " : " + second);
It must work
LocalTime t1 = LocalTime.parse('03:33:24')
LocalTime t2 = LocalTime.parse('03:13:41')
t1.plusHours(t2.hour)
.plusMinutes(t2.minute)
.plusSeconds(t2.second)
.plusNanos(t2.nano)
I have a requirement where I need to find out number of months between two dates including extra days.
example:
start date:01/01/2014
end date:21/02/2014
LocalDate startDate = new LocalDate(startDate1);
LocalDate endDate = new LocalDate(endDate1);
PeriodType monthDay =PeriodType.yearMonthDay().withYearsRemoved();
Period difference = new Period(startDate, endDate, monthDay);
int months = difference.getMonths();
int days = difference.getDays()
the out put I will get is:
months:1 days:20
but my requirement is I want get total months including that extra day.
like:1.66 months.
How to get this one in java?
In order to be able to say 1.66 months you need to define how long a month is. It's not always the same. If you assume that a month is 30 days long then you can solve this by using:
Date startDate = new SimpleDateFormat("dd/MM/yyyy").parse("01/01/2014");
Date endDate = new SimpleDateFormat("dd/MM/yyyy").parse("21/02/2014");
double result = (endDate.getTime() - startDate.getTime()) / (1000D*60*60*24*30);
This gives us 1.7 and if you divide with 31 you get 1.6451612903225807.
If you want a better (but not perfect) approximation of how long a month is you can try 365/12 which will give you 1.6767123287671233 but still this is not perfect because leap years have 366 days.
The problem though is not with the formula, but with the problem definition. Nobody in real life says "I'll be there in exactly 1.66 months" and nobody will ever ask you to convert 1.66 months in days.
This is my own answer, a variation on cherouvim's
final Date startDate = new GregorianCalendar (2014, 0, 1).getTime ();
final Date endDate = new GregorianCalendar (2014, 1, 21).getTime ();
System.out.println ((endDate.getTime () - startDate.getTime ()) / (float) (1000L * 60 * 60 * 24 * 30));
How can I convert the number of days to number of months and days using Joda-Time. For example, when I have 33 days, it should display 1 month and 2 days.
public static void main(String[]args)
{
Calendar calendar = new GregorianCalendar();
int years = calendar.get(Calendar.YEAR);
int month = (calendar.get(Calendar.MONTH))+1;
int day = calendar.get(Calendar.DATE);
DateTime startDate = new DateTime(years, month, day, 0, 0, 0, 0);
DateTime endDate = new DateTime(2014, 7, 3, 0, 0, 0, 0);
Days d = Days.daysBetween(startDate, endDate);
int days = d.getDays();
int t = 1000 * 60 * 60 *24;
int days = days/t;
System.out.println(days);
}
You can use class org.joda.time.Period for this.
Example:
Period p = new Period(startDate, endDate, PeriodType.yearMonthDayTime());
System.out.println(p.getMonths());
System.out.println(p.getDays());
Trying to create a decimal fraction number to represent months makes no sense to me, as months have different numbers of days (28, 29, 30, 31).
ISO 8601
The sensible ISO 8601 standard defines a textual way to represent a span of time in terms of months and days, called Durations. Joda-Time has a class for this purpose called Period. Forgive the mismatch in terms, as there is no standard definition of date-time terminology yet.
For an example of using the Period class, see this other answer by Ilya on this question.
ISO Duration
The textual format is PnYnMnDTnHnMnS where P means "Period" and the T separates the date portion from time portion. The other parts are optional. One month and two days would be P1M2D. The Joda-Time Period class both parses and generates such strings.