How do I add/subtract two time objects. I have two time objects (arrival and departure) in format of "yyyy/MMM/dd HH:mm:ss". I need to print the difference between departure and arrival time. I am generating time ad below:
public String getTime() {
Calendar currentDate = Calendar.getInstance();
SimpleDateFormat formatter = new SimpleDateFormat("yyyy/MMM/dd HH:mm:ss");
return formatter.format(currentDate.getTime());
}
Can I get time in mills and than format it when I needed to print ?
Take a look at Joda Time library.
You can easily subtract and add DateTime and find out interval easily :
// interval from start to end
DateTime start = new DateTime(2004, 12, 25, 0, 0, 0, 0);
DateTime end = new DateTime(2005, 1, 1, 0, 0, 0, 0);
Interval interval = new Interval(start, end);
something like this.....
public long getTimeDiff() throws Exception {
String arrival = "2011/Nov/10 13:15:24";
String departure = "2011/Jan/10 13:15:24";
SimpleDateFormat formatter = new SimpleDateFormat("yyyy/MMM/dd HH:mm:ss");
java.util.Date date1 = formatter.parse(arrival);
java.util.Date date2 = formatter.parse(departure);
return date2.getTime() - date1.getTime();
}
Convert them to date and then to long and subtract, that would give the time difference in milli seconds,
Date d1 = DateFormat.parse(time1);
Date d2 = DateFormat.parse(time2);
long diffInMilliSeconds = d1.getTime()-d2.getTime();
You can get time in milliseconds for both calendars using getTime method. When you can convert the result of subtraction to measure units that you need. If you're going to work with time/duration seriously when take a look at Joda library
Upd. You should call getTime twice. First object being returned is Date, when you call getTime on Date you get long value.
I would convert the two time/Date objects in milliseconds. Then i would subtract them (we are dealing with longs).
Then i would create a Date object from the resulting long value. After that you can construct a Calendar with Calendar.setDate(Date).
Regards!
Yes, start with your Dates and use getTime() to convert to milliseconds (or getTimeInMillis() for your Calendars). That give you long values you can subtract. That's the easy part.
Then you can convert these milliseconds into a readable format yourself. But it probably makes sense to use a packaged library to do it.
Some folks like the Joda library for these types of date calculations. I find Commons Lang is fantastic. It provides DateUtils which is useful if you find you want to perform calculations like rounding or truncating your dates to the nearest minute or hour etc. The part that will be most useful to you is the DurationFormatUtils class which gives you functions like formatDurationHMS to format into nice Hour:Minute:Second display and formatDurationWords to get text (fancy!) or other similar functions to easily format your milliseconds into a nicely human-readable format.
Related
I want to compare time difference in hours. Based on current time and time I get from database.
DateFormat sdf = new SimpleDateFormat(“yyyy-MM-dd HH:mm:ss”);
Date date = new Date();
Logger.info(“current time is”,sdf.format(date));
// gives date in 2019-11-06 17:03:54
// dB gives following record
Date successDate = loader.getLastSuccess();
// gives date in 2019-10-31T:56:08.066+0000
Both formats are different how to get the time difference any suggestion experts
You can use the java-8 date API Duration to get the duration between both the dates
long hours = Duration.between(date1.toInstant(), date2.toInstant()).toHours();
Note : It can return negative value also here
the number of hours in the duration, may be negative
public int getHours() on util.Date is deprecated, so convert them to Instant and use Duration.between and also i will suggest to use java-8 Date API instead of older version Date
If you want difference in hours as double, you can do this;
Date your_date = loader.getLastSuccess();
Date currentDate = new Date();
double hourdifference = (currentDate.getTime() - your_date.getTime()) / 3600000.0;
You can get long or int, just change 3600000.0 to 3600000, and make the variable int or long
Calculating the difference between two dates (java.util.Date) in terms of no. of days look like very simple and we can find different ways to do that. I used the following code to calculate the date difference:
public static long daysBetween(Calendar startDate, Calendar endDate) {
Calendar date = (Calendar) startDate.clone();
long daysBetween = 0;
while (date.before(endDate)) {
date.add(Calendar.DAY_OF_MONTH, 1);
daysBetween++;
}
return daysBetween;
}
In main(), I used the following two dates :
Calendar c1 = Calendar.getInstance();
c1.set(2011, 1, 1);
Calendar c2 = Calendar.getInstance();
c2.set(2011, 1, 31);
long difference = daysBetween(c1, c2); //
But the value of the variable difference is not consistent. It is sometimes 30 and sometimes 31. So, why that might have happened.
Is there any solution to use the method results a consistent output ?
You're setting the date part of the calendars, but not the time part.
Sometimes the clock will tick between the calls to getInstance() and sometimes it won't, hence the inconsistency.
Options:
Set the time as well as the date, e.g. to midnight
Use a better date/time library - Joda Time - which has a more suitable representation (LocalDate). An important moral here is that if you can find a type which represents the exact information you have, and nothing else, that's likely to be a good fit and cause fewer complications.
Using LocalDate, you wouldn't even have to do the loop as Joda Time has good support for computing the differences between two values anyway.
LocalDate date1 = new LocalDate(2011, 1, 1);
LocalDate date2 = new LocalDate(2011, 1, 31);
Days period = Days.daysBetween(days1, days2);
int days = period.getDays();
You are only setting the year, month and day. The hours, minutes, seconds and milli-seconds are the current time (and thus different every time you run it)
I suggest you use Joda Time's LocalDate instead as it appears to does exactly what you want.
The date is selected by the user using a drop down for year, month and day. I have to compare the user entered date with today's date. Basically see if they are the same date. For example
the user entered 02/16/2012. And if today is 02/16/2012 then I have to display a message. How do I do it?
I tried using milliseconds but that gives out wrong results.
And what kind of object are you getting back? String, Calendar, Date? You can get that string and compare it, at least that you think you'll have problems with order YYYY MM DD /// DD MM YYY in that case I suggest to create a custom string based on your spec YYYYMMDD and then compare them.
Date d1 = new Date();
Date d2 = new Date();
String day1 = d1.getYear()+"/"+d1.getMonth()+"/"+d1.getDate();
String day2 = d2.getYear()+"/"+d2.getMonth()+"/"+d2.getDate();
if(day1.equals(day2)){
System.out.println("Same day");
}
Dates in java are moments in time, with a resolution of "to the millisecond". To compare two dates effectively, you need to first set both dates to the "same time" in hours, minutes, seconds, and milliseconds. All of the "setTime" methods in a java.util.Date are depricated, because they don't function correctly for the internationalization and localization concerns.
To "fix" this, a new class was introduced GregorianCalendar
GregorianCalendar cal1 = new GregorianCalendar(2012, 11, 17);
GregorianCalendar cal2 = new GregorianCalendar(2012, 11, 17);
return cal1.equals(cal2); // will return true
The reason that GregorianCalendar works is related to the hours, minutes, seconds, and milliseconds being initialized to zero in the year, month, day constructor. You can attempt to approximate such with java.util.Date by using deprecated methods like setHours(0); however, eventually this will fail due to a lack of setMillis(0). This means that to use the Date format, you need to grab the milliseconds and perform some integer math to set the milliseconds to zero.
date1.setHours(0);
date1.setMinutes(0);
date1.setSeconds(0);
date1.setTime((date1.getTime() / 1000L) * 1000L);
date2.setHours(0);
date2.setMinutes(0);
date2.setSeconds(0);
date2.setTime((date2.getTime() / 1000L) * 1000L);
return date1.equals(date2); // now should do a calendar date only match
Trust me, just use the Calendar / GregorianCalendar class, it's the way forward (until Java adopts something more sophisticated, like joda time.
There is two way you can do it. first one is format both the date in same date format or handle date in string format.
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
String date1 = sdf.format(selectedDate);
String date2 = sdf.format(compareDate);
if(date1.equals(date2)){
}else{
}
Or
Calendar toDate = Calendar.getInstance();
Calendar nowDate = Calendar.getInstance();
toDate.set(<set-year>,<set-month>,<set-date->);
if(!toDate.before(nowDate))
//display your report
else
// don't display the report
Above answers are correct but consider using JodaTime - its much simpler and intuitive API.
You could set DateTime using with* methods and compare them.
Look at this answer
Hello I have this excerpt of code:
end = new DateTime(mergeToDateTime(this.endDate, this.empEndTime));
Duration extraTime = new Duration(this.preTime.getTime()); //add the first 30 mins
extraTime = extraTime.plus(new Duration(this.postTime.getTime())); //add the second 30 mins
end = end.plus(extraTime); // extraTime = -3600?
When I look in the debugger my durations are always coming up negative. I have no idea why this is, even though according to the API, it is possible to create a duration out of the a long type, hence the getTime(). (preTime and postTime are java.sql.Time types)
I guess your instances of java.sql.Time were created in such a way that their millisecond values include timezone offset.
For example, deprecated java.sql.Time(int hour, int minute, int second) constructor takes offset of the current timezone into account:
System.out.println(new Time(1, 0, 0).getTime()); // Prints -7200000 in UTC+3 timezone
It looks like timezone offset is introduced by JDBC driver, and it can be easily compensated by converting java.sql.Time to LocalTime (and vice versa):
LocalTime lt = new LocalTime(time);
Then you can convert LocalTime to duration:
Duration d = new Duration(lt.getMillisOfDay());
Aren't you starting out wrong when you use an instant in time as duration? The constructor signature you are using is Duration(long duration), not Duration(long startInstant) -- there is no such constructor, in fact.
This question already has answers here:
Closed 11 years ago.
Possible Duplicates:
Calculating difference in dates in Java
How can I calculate a time span in Java and format the output?
Say you were given two dates as strings and they are in this format 8/11/11 9:16:36 PM how would I go about converting them to java Date objects so that I can then calculate the difference between two dates?
As long as both times are in GMT/UTC, you can do date1.getTime() - date2.getTime() and then divide the result by 86400000 to get number of days. The rest is probably pretty intuitive.
EDIT -- based on edited question
To convert Strings into dates, use the SimpleDateFormat class.
String yourDateString = "8/11/11 9:16:36 PM";
SimpleDateFormat format =
new SimpleDateFormat("MM/dd/yy HH:mm:ss a");
Date yourDate = format.parse(yourDateString);
The majority of Date's getters are deprecated, replaced with Calendar methods. Here's how you would do it
Date date1, date2; //initialized elsewhere
Calendar day1 = new Calendar();
day1.setTime(date1)
Calendar day2 = new Calendar();
day2.setTime(date2);
int yearDiff, monthDiff, dayDiff, hourDiff, minuteDiff, secondDiff;
yearDiff = Math.abs(day1.get(Calendar.YEAR)-day2.get(Calendar.YEAR));
monthDiff = Math.abs(day1.get(Calendar.MONTH)-day2.get(Calendar.MONTH));
dayDiff = Math.abs(day1.get(Calendar.DAY_OF_YEAR)-day2.get(Calendar.DAY_OF_YEAR));
hourDiff = Math.abs(day1.get(Calendar.HOUR_OF_DAY)-day2.get(Calendar.HOUR_OF_DAY));
minuteDiff = Math.abs(day1.get(Calendar.MINUTE)-day2.get(Calendar.MINUTE));
secondDiff = Math.abs(day1.get(Calendar.SECOND)-day2.get(Calendar.SECOND));
Then you can do whatever you like with those numbers.
define a SimpleDateFormat matching your format (the java doc is pretty straighforward), then use the parse method to get a the proper Date object, from which you can easily compute the difference between the two dates.
Once you have this difference, the best is probably to compute "manually" the number of days / hours / minutes / seconds, although it might be possible to again use a SimpleDateFormat (or some other formatting mechanism) to display the proper values in a generic way.