Java Calculate the number of days between two dates

Question

Possible Duplicate    Calculating the Difference Between Two Java Date Instances       In Java  I want to calculate the number of days between two dates   In my database they are stored as a DATE datatype  but in my code they are strings   I want to calculate the no of days between those two strings

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here s a small program which may help you   import java util     public class DateDifference       public static void main String args             DateDifference difference   new DateDifference               DateDifference             Calendar cal1   new GregorianCalendar            Calendar cal2   new GregorianCalendar             cal1 set 2010  12  1            cal2 set 2011  9  31           System out println  Days    daysBetween cal1 getTime   cal2 getTime                 public int daysBetween Date d1  Date d2            return  int    d2 getTime   - d1 getTime       1000   60   60   24

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My best solution  so far  for calculating the number of days difference        This assumes that you already have two Date objects  startDate  endDate     Also  that you want to ignore any time portions  Calendar startCale new GregorianCalendar    Calendar endCal new GregorianCalendar     startCal setTime startDate   endCal setTime endDate    endCal add Calendar YEAR -startCal get Calendar YEAR    endCal add Calendar MONTH -startCal get Calendar MONTH    endCal add Calendar DATE -startCal get Calendar DATE     int daysDifference endCal get Calendar DAY OF YEAR     Note  however  that this assumes less than a year s difference

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I know this thread is two years old now  I still don t see a correct answer here   Unless you want to use Joda or have Java 8 and if you need to subract dates influenced by daylight saving   So I have written my own solution  The important aspect is that it only works if you really only care about dates because it s necessary to discard the time information  so if you want something like 25 06 2014 - 01 01 2010   1636  this should work regardless of the DST   private static SimpleDateFormat simpleDateFormat   new SimpleDateFormat  dd MM yyyy     public static long getDayCount String start  String end      long diff   -1    try       Date dateStart   simpleDateFormat parse start       Date dateEnd   simpleDateFormat parse end          time is always 00 00 00  so rounding should help to ignore the missing hour when going from winter to summer time  as well as the extra hour in the other direction     diff   Math round  dateEnd getTime   - dateStart getTime       double  86400000       catch  Exception e          handle the exception according to your own situation       return diff      As the time is always 00 00 00  using double and then Math round   should help to ignore the missing 3600000 ms  1 hour  when going from winter to summer time  as well as the extra hour if going from summer to winter   This is a small JUnit4 test I use to prove it    Test public void testGetDayCount       String startDateStr    01 01 2010     GregorianCalendar gc   new GregorianCalendar locale     try       gc setTime simpleDateFormat parse startDateStr        catch  Exception e           for  long i   0  i  lt  10000  i          String dateStr   simpleDateFormat format gc getTime         long dayCount   getDayCount startDateStr  dateStr       assertEquals  dayCount must be equal to the loop index i     i  dayCount       gc add GregorianCalendar DAY OF YEAR  1               or if you want to see what it does  life   replace the assertion with just   System out println  i      i           dayCount     - getDayCount     startDateStr          dateStr               and this is what the output should look like     i  0   0  - getDayCount 01 01 2010  01 01 2010    i  1   1  - getDayCount 01 01 2010  02 01 2010    i  2   2  - getDayCount 01 01 2010  03 01 2010    i  3   3  - getDayCount 01 01 2010  04 01 2010          i  1636   1636  - getDayCount 01 01 2010  25 06 2014          i  9997   9997  - getDayCount 01 01 2010  16 05 2037    i  9998   9998  - getDayCount 01 01 2010  17 05 2037    i  9999   9999  - getDayCount 01 01 2010  18 05 2037

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This function is good for me   public static int getDaysCount Date begin  Date end        Calendar start   org apache commons lang time DateUtils toCalendar begin       start set Calendar MILLISECOND  0       start set Calendar SECOND  0       start set Calendar MINUTE  0       start set Calendar HOUR OF DAY  0        Calendar finish   org apache commons lang time DateUtils toCalendar end       finish set Calendar MILLISECOND  999       finish set Calendar SECOND  59       finish set Calendar MINUTE  59       finish set Calendar HOUR OF DAY  23        long delta   finish getTimeInMillis   - start getTimeInMillis        return  int  Math ceil delta    1000 0   60   60   24

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Java 8 and later  ChronoUnit between Use instances of ChronoUnit to calculate amount of time in different units  days months  seconds   For Example  ChronoUnit DAYS between startDate endDate

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I m really really REALLY new at Java  so i m sure that there s an even better way to do what i m proposing   I had this same demand and i did it using the difference between the DAYOFYEAR of the two dates  It seemed an easier way to do it      I can t really evaluate this solution in performance and stability terms  but i think it s ok   here        public static void main String   args  throws ParseException        Made this part of the code just to create the variables i ll use    I m in Brazil and the date format here is DD MM YYYY  but wont be an issue to you guys     It will work anyway with your format       String s1    18 09 2014        String s2    01 01 2014       DateFormat f   DateFormat getDateInstance        Date date1   f parse s1        Date date2   f parse s2         Here s the part where we get the days between two dates       Calendar day1   Calendar getInstance        Calendar day2   Calendar getInstance         day1 setTime date1       day2 setTime date2        int daysBetween   day1 get Calendar DAY OF YEAR  - day2 get Calendar DAY OF YEAR               Some code just to show the result        f   DateFormat getDateInstance DateFormat MEDIUM       System out println  There s     daysBetween     days between     f format day1 getTime        and     f format day2 getTime                       In this case  the output would be  remembering that i m using the Date Format DD MM YYYY     There s 260 days between 18 09 2014 and 01 01 2014

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try this code       Calendar cal1   new GregorianCalendar         Calendar cal2   new GregorianCalendar          SimpleDateFormat sdf   new SimpleDateFormat  ddMMyyyy          Date date   sdf parse  your first date         cal1 setTime date       date   sdf parse  your second date         cal2 setTime date          cal1 set 2008  8  1           cal2 set 2008  9  31        System out println  Days    daysBetween cal1 getTime   cal2 getTime        this function        public int daysBetween Date d1  Date d2                return  int    d2 getTime   - d1 getTime       1000   60   60   24

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Well to start with  you should only deal with them as strings when you have to  Most of the time you should work with them in a data type which actually describes the data you re working with   I would recommend that you use Joda Time  which is a much better API than Date Calendar  It sounds like you should use the LocalDate type in this case  You can then use   int days   Days daysBetween date1  date2  getDays

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http   en wikipedia org wiki Julian day public static int julianDay int year  int month  int day      int a    14 - month    12    int y   year   4800 - a    int m   month   12   a - 3    int jdn   day    153   m   2  5   365 y   y 4 - y 100   y 400 - 32045    return jdn     public static int diff int y1  int m1  int d1  int y2  int m2  int d2      return julianDay y1  m1  d1  - julianDay y2  m2  d2

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If you re sick of messing with java you can just send it to db2 as part of your query   select date1  date2  days date1  - days date2  from table   will return date1  date2 and the difference in days between the two

[java] Java, Calculate the number of days between two dates

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