Comparing two java util Dates to see if they are in the same day

Question

I need to compare two Dates  e g  date1 and date2  and come up with a boolean sameDay which is true of the two Dates share the same day  and false if they are not   How can I do this  There seems to be a whirlwind of confusion here    and I would like to avoid pulling in other dependencies beyond the JDK if at all possible   to clarify  if date1 and date2 share the same year  month  and day  then sameDay is true  otherwise it is false  I realize this requires knowledge of a timezone    it would be nice to pass in a timezone but I can live with either GMT or local time as long as I know what the behavior is   again  to clarify   date1   2008 Jun 03 12 56 03 date2   2008 Jun 03 12 59 44     gt  sameDate   true  date1   2009 Jun 03 12 56 03 date2   2008 Jun 03 12 59 44     gt  sameDate   false  date1   2008 Aug 03 12 00 00 date2   2008 Jun 03 12 00 00     gt  sameDate   false

User · Answer

you can apply the same logic as the SimpleDateFormat solution without relying on SimpleDateFormat  date1 getFullYear   10000   date1 getMonth   100   date1 getDate       date2 getFullYear   10000   date2 getMonth   100   date2 getDate

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Calendar cal1   Calendar getInstance    Calendar cal2   Calendar getInstance    cal1 setTime date1   cal2 setTime date2   boolean sameDay   cal1 get Calendar DAY OF YEAR     cal2 get Calendar DAY OF YEAR   amp  amp                    cal1 get Calendar YEAR     cal2 get Calendar YEAR     Note that  same day  is not as simple a concept as it sounds when different time zones can be involved  The code above will for both dates compute the day relative to the time zone used by the computer it is running on  If this is not what you need  you have to pass the relevant time zone s  to the Calendar getInstance   calls  after you have decided what exactly you mean with  the same day    And yes  Joda Time s LocalDate would make the whole thing much cleaner and easier  though the same difficulties involving time zones would be present

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private boolean isSameDay Date date1  Date date2            Calendar calendar1   Calendar getInstance            calendar1 setTime date1           Calendar calendar2   Calendar getInstance            calendar2 setTime date2           boolean sameYear   calendar1 get Calendar YEAR     calendar2 get Calendar YEAR           boolean sameMonth   calendar1 get Calendar MONTH     calendar2 get Calendar MONTH           boolean sameDay   calendar1 get Calendar DAY OF MONTH     calendar2 get Calendar DAY OF MONTH           return  sameDay  amp  amp  sameMonth  amp  amp  sameYear

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Java 8  If you are using Java 8 in your project and comparing java sql Timestamp  you could use the LocalDate class   sameDate   date1 toLocalDateTime   toLocalDate   equals date2 toLocalDateTime   toLocalDate       If you are using java util Date  have a look at Istvan answer which is less ambiguous

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For Kotlin devs this is the version with comparing formatted strings approach   val sdf   SimpleDateFormat  yyMMdd   if  sdf format date1     sdf format date2            same day     It s not the best way  but it s short and working

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How about   SimpleDateFormat fmt   new SimpleDateFormat  yyyyMMdd    return fmt format date1  equals fmt format date2      You can also set the timezone to the SimpleDateFormat  if needed

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Convert dates to Java 8 java time LocalDate  as seen here   LocalDate localDate1   date1 toInstant   atZone ZoneId systemDefault    toLocalDate    LocalDate localDate2   date2 toInstant   atZone ZoneId systemDefault    toLocalDate        compare dates assertTrue  Not on the same day   localDate1 equals localDate2

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Joda-Time  As for adding a dependency  I m afraid the java util Date  amp   Calendar really are so bad that the first thing I do to any new project is add the Joda-Time library  In Java 8 you can use the new java time package  inspired by Joda-Time   The core of Joda-Time is the DateTime class  Unlike java util Date  it understands its assigned time zone  DateTimeZone   When converting from j u Date  assign a zone   DateTimeZone zone   DateTimeZone forID   America Montreal     DateTime dateTimeQu  bec   new DateTime  date   zone      LocalDate  One way to verify if two date-times land on the same date is to convert to LocalDate objects    That conversion depends on the assigned time zone  To compare LocalDate objects  they must have been converted with the same zone   Here is a little utility method   static public Boolean sameDate   DateTime dt1   DateTime dt2         LocalDate ld1   new LocalDate  dt1           LocalDate determination depends on the time zone         So be sure the date-time values are adjusted to the same time zone      LocalDate ld2   new LocalDate  dt2 withZone  dt1 getZone            Boolean match   ld1 equals  ld2        return match      Better would be another argument  specifying the time zone rather than assuming the first DateTime object   s time zone should be used   static public Boolean sameDate   DateTimeZone zone   DateTime dt1   DateTime dt2         LocalDate ld1   new LocalDate  dt1 withZone  zone             LocalDate determination depends on the time zone         So be sure the date-time values are adjusted to the same time zone      LocalDate ld2   new LocalDate  dt2 withZone  zone          return ld1 equals  ld2        String Representation  Another approach is to create a string representation of the date portion of each date-time  then compare strings   Again  the assigned time zone is crucial   DateTimeFormatter formatter   ISODateTimeFormat date        Static method  String s1   formatter print  dateTime1    String s2   formatter print  dateTime2 withZone  dt1 getZone         Boolean match   s1 equals  s2    return match    Span of Time  The generalized solution is to define a span of time  then ask if the span contains your target  This example code is in Joda-Time 2 4  Note that the  midnight -related classes are deprecated  Instead use the withTimeAtStartOfDay method  Joda-Time offers three classes to represent a span of time in various ways  Interval  Period  and Duration   Using the  Half-Open  approach where the beginning of the span is inclusive and the ending exclusive   The time zone of the target can be different than the time zone of the interval   DateTimeZone timeZone   DateTimeZone forID   Europe Paris     DateTime target   new DateTime  2012  3  4  5  6  7  timeZone    DateTime start   DateTime now  timeZone   withTimeAtStartOfDay    DateTime stop   start plusDays  1   withTimeAtStartOfDay    Interval interval   new Interval  start  stop    boolean containsTarget   interval contains  target      java time  Java 8 and later comes with the java time framework  Inspired by Joda-Time  defined by JSR 310  and extended by the ThreeTen-Extra project  See Tutorial    The makers of Joda-Time have instructed us all to move to java time as soon as is convenient  In the meantime Joda-Time continues as an actively maintained project  But expect future work to occur only in java time and ThreeTen-Extra rather than Joda-Time   To summarize java time in a nutshell    An Instant is a moment on the timeline in UTC  Apply a time zone  ZoneId  to get a ZonedDateTime object  To move off the timeline  to get the vague indefinite idea of a date-time  use the  local  classes  LocalDateTime  LocalDate  LocalTime    The logic discussed in the Joda-Time section of this Answer applies to java time   The old java util Date class has a new toInstant method for conversion to java time    Instant instant   yourJavaUtilDate toInstant       Convert into java time type    Determining a date requires a time zone    ZoneId zoneId   ZoneId of   America Montreal       We apply that time zone object to the Instant to obtain a ZonedDateTime  From that we extract a date-only value  a LocalDate  as our goal is to compare dates  not hours  minutes  etc      ZonedDateTime zdt1   ZonedDateTime ofInstant  instant   zoneId    LocalDate localDate1   LocalDate from  zdt1      Do the same to the second java util Date object we need for comparison  I   ll just use the current moment instead   ZonedDateTime zdt2   ZonedDateTime now  zoneId    LocalDate localDate2   LocalDate from  zdt2      Use the special isEqual method to test for the same date value   Boolean sameDate   localDate1 isEqual  localDate2

User · Answer

You can avoid external dependencies and the performance hit of using Calendar by calculating the Julian Day Number for each of the dates and then comparing these   public static boolean isSameDay Date date1  Date date2            Strip out the time part of each date      long julianDayNumber1   date1 getTime     MILLIS PER DAY      long julianDayNumber2   date2 getTime     MILLIS PER DAY          If they now are equal then it is the same day      return julianDayNumber1    julianDayNumber2

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in addition to Binil Thomas solution  public static boolean isOnSameDay Timestamp    dates        SimpleDateFormat fmt   new SimpleDateFormat  yyyyMMdd        String date1   fmt format dates 0        for  Timestamp date   dates            if   fmt format date  equals date1                 return false                      return true      usage      isOnSameDay date1 date2 date3         or      isOnSameDay mydates

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FOR ANDROID USERS   You can use DateUtils isToday dateMilliseconds  to check whether the given date is current day or not   API reference  https   developer android com reference android text format DateUtils html isToday long

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I use the  apache commons lang  package to do this  namely org apache commons lang time DateUtils   boolean samedate   DateUtils isSameDay date1  date2      Takes either Calendar or Date objects

[java] Comparing two java.util.Dates to see if they are in the same day

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