How to obtain the start time and end time of a day

Question

How to obtain the start time and end time of a day   code like this is not accurate    private Date getStartOfDay Date date        Calendar calendar   Calendar getInstance        int year   calendar get Calendar YEAR       int month   calendar get Calendar MONTH       int day   calendar get Calendar DATE       calendar set year  month  day  0  0  0       return calendar getTime       private Date getEndOfDay Date date        Calendar calendar   Calendar getInstance        int year   calendar get Calendar YEAR       int month   calendar get Calendar MONTH       int day   calendar get Calendar DATE       calendar set year  month  day  23  59  59       return calendar getTime        It is not accurate to the millisecond

User · Answer

I had several inconveniences with all the solutions because I needed the type of Instant variable and the Time Zone always interfered changing everything, then combining solutions I saw that this is a good option.

        LocalDate today = LocalDate.now();
        Instant startDate = Instant.parse(today.toString()+"T00:00:00Z");
        Instant endDate = Instant.parse(today.toString()+"T23:59:59Z");

and we have as a result

        startDate = 2020-01-30T00:00:00Z
        endDate = 2020-01-30T23:59:59Z

I hope it helps you

User · Answer

private Date getStartOfDay Date date        Calendar calendar   Calendar getInstance        int year   calendar get Calendar YEAR       int month   calendar get Calendar MONTH       int day   calendar get Calendar DATE       calendar setTimeInMillis 0       calendar set year  month  day  0  0  0       return calendar getTime           private Date getEndOfDay Date date        Calendar calendar   Calendar getInstance        int year   calendar get Calendar YEAR       int month   calendar get Calendar MONTH       int day   calendar get Calendar DATE       calendar setTimeInMillis 0       calendar set year  month  day  23  59  59       return calendar getTime            calendar setTimeInMillis 0   gives you accuracy upto milliseconds

User · Answer

I know it s a bit late  but in case of Java 8  if you are using OffsetDateTime  which offers a lot of advantages  such as TimeZone  Nanoseconds  etc    you can use the following code   OffsetDateTime reallyEndOfDay   someDay withHour 23  withMinute 59  withSecond 59  withNano 999999999      output  2019-01-10T23 59 59 999999999Z

User · Answer

this will work for user in time zone MST with 7 off set or UTC with saving time      I have tried all the above and they fail the only solution is to use some math    the trick is to rely on  newdate is time         strtotime is corrupt it tries to read to many minds    convert to time to use with javascript 1000     dnol   strtotime  today   1000    dn     newdate 1000 -86400000    dz  dn 86400000         divide into days   dz floor  dz         filter off excess time   dzt  dz 86400000         put back into days UTC   jsDate  dzt 1  7 3600000          7 is the off set you can store the 7 in database   dzt  dzt-3600000         adjusment for summerTime UTC additional table for these dates will drive you crazy    solution get users  time off sets  with browser  up date to data base for user with ajax when they ain t lookin      lt  php   t time     echo  t    quot  lt br gt  quot     echo date  quot Y-m-d quot   t     echo   lt BR gt    dnol   echo   lt BR gt    dzt   lt BR gt     echo date  quot Y-m-d quot   dzt 1000           convert back for php  1000  echo   lt BR gt     echo date  Y-m-d h i s   dzt 1000        gt

User · Answer

Another one solution which does not depend on any framework is   static public Date getStartOfADay Date day        final long oneDayInMillis   24   60   60   1000      return new Date day getTime     oneDayInMillis   oneDayInMillis      static public Date getEndOfADay Date day        final long oneDayInMillis   24   60   60   1000      return new Date  day getTime     oneDayInMillis   1    oneDayInMillis - 1       Note that it returns UTC based time

User · Answer

Shortest answer  given your timezone being TZ  LocalDateTime start   LocalDate now TZ  atStartOfDay   LocalDateTime end   start plusDays 1   Compare using isAfter   and isBefore   methods  or convert it using toEpochSecond   or toInstant   methods

User · Answer

I think the easiest would be something like      Joda Time  DateTime dateTime new DateTime      StartOfDayMillis   dateTime withMillis System currentTimeMillis    withTimeAtStartOfDay   getMillis    EndOfDayMillis   dateTime withMillis StartOfDayMillis  plusDays 1  minusSeconds 1  getMillis      These millis can be then converted into Calendar Instant or LocalDate as per your requirement with Joda Time

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The following code takes the OP s original formula  and adjusts for the ms inexactness      private static Date getStartOfDay             Calendar calendar   Calendar getInstance            int year   calendar get Calendar YEAR           int month   calendar get Calendar MONTH           int day   calendar get Calendar DATE           calendar set year  month  day  0  0  0           long approximateTimestamp   calendar getTime   getTime            long extraMillis    approximateTimestamp   1000           long exactTimestamp   approximateTimestamp - extraMillis          return new Date exactTimestamp              private static Date getEndOfDay             Calendar calendar   Calendar getInstance            int year   calendar get Calendar YEAR           int month   calendar get Calendar MONTH           int day   calendar get Calendar DATE           calendar set year  month  day  23  59  59           long approximateTimestamp   calendar getTime   getTime            long extraMillis    approximateTimestamp   1000           long exactTimestamp   approximateTimestamp - extraMillis   999          return new Date exactTimestamp          Unlike many other answers on this thread  it is compatible with older versions of Java and Android APIs

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tl dr LocalDate                          Represents an entire day  without time-of-day and without time zone   now                               Capture the current date      ZoneId of   quot Asia Tokyo quot         Returns a  ZoneId  object                                     Returns a  LocalDate  object   atStartOfDay                      Determines the first moment of the day as seen on that date in that time zone  Not all days start at 00 00      ZoneId of   quot Asia Tokyo quot                                        Returns a  ZonedDateTime  object   Start of day Get the full length of the today as seen in a time zone  Using Half-Open approach  where the beginning is inclusive while the ending is exclusive  This approach solves the flaw in your code that fails to account for the very last second of the day  ZoneId zoneId   ZoneId of   quot Africa Tunis quot      LocalDate today   LocalDate now  zoneId       ZonedDateTime zdtStart   today atStartOfDay  zoneId     ZonedDateTime zdtStop   today plusDays  1   atStartOfDay  zoneId       zdtStart toString     2020-01-30T00 00 01 00 Africa Tunis    zdtStop toString     2020-01-31T00 00 01 00 Africa Tunis   See the same moments in UTC  Instant start   zdtStart toInstant     Instant stop   zdtStop toInstant       start toString     2020-01-29T23 00 00Z   stop toString     2020-01-30T23 00 00Z  If you want the entire day of a date as seen in UTC rather than in a time zone  use OffsetDateTime  LocalDate today   LocalDate now  ZoneOffset UTC       OffsetDateTime odtStart   today atTime  OffsetTime MIN     OffsetDateTime odtStop   today plusDays  1   atTime  OffsetTime MIN       odtStart toString     2020-01-30T00 00 18 00   odtStop toString     2020-01-31T00 00 18 00  These OffsetDateTime  objects will already be in UTC  but you can call toInstant if you need such objects which are always in UTC by definition  Instant start   odtStart toInstant     Instant stop   odtStop toInstant       start toString     2020-01-29T06 00 00Z   stop toString     2020-01-30T06 00 00Z  Tip  You may be interested in adding the ThreeTen-Extra library to your project to use its Interval class to represent this pair of Instant objects  This class offers useful methods for comparison such as abuts  overlaps  contains  and more  Interval interval   Interval of  start   stop       interval toString     2020-01-29T06 00 00Z 2020-01-30T06 00 00Z  Half-Open The answer by mprivat is correct  His point is to not try to obtain end of a day  but rather compare to  quot before start of next day quot   His idea is known as the  quot Half-Open quot  approach where a span of time has a beginning that is inclusive while the ending is exclusive   The current date-time frameworks of Java  java util Date Calendar and Joda-Time  both use milliseconds from the epoch  But in Java 8  the new JSR 310 java time   classes use nanoseconds resolution  Any code you wrote based on forcing the milliseconds count of last moment of day would be incorrect if switched to the new classes  Comparing data from other sources becomes faulty if they employ other resolutions  For example  Unix libraries typically employ whole seconds  and databases such as Postgres resolve date-time to microseconds  Some Daylight Saving Time changes happen over midnight which might further confuse things    Joda-Time 2 3 offers a method for this very purpose  to obtain first moment of the day  withTimeAtStartOfDay    Similarly in java time  LocalDate  atStartOfDay  Search StackOverflow for  quot joda half-open quot  to see more discussion and examples  See this post  Time intervals and other ranges should be half-open  by Bill Schneider  Avoid legacy date-time classes The java util Date and  Calendar classes are notoriously troublesome  Avoid them  Use java time classes  The java time framework is the official successor of the highly successful Joda-Time library  java time The java time framework is built into Java 8 and later  Back-ported to Java 6  amp  7 in the ThreeTen-Backport project  further adapted to Android in the ThreeTenABP project  An Instant is a moment on the timeline in UTC with a resolution of nanoseconds  Instant instant   Instant now     Apply a time zone to get the wall-clock time for some locality  ZoneId zoneId   ZoneId of   quot America Montreal quot     ZonedDateTime zdt   ZonedDateTime ofInstant  instant   zoneId     To get the first moment of the day go through the LocalDate class and its atStartOfDay method  ZonedDateTime zdtStart   zdt toLocalDate   atStartOfDay  zoneId     Using Half-Open approach  get first moment of following day  ZonedDateTime zdtTomorrowStart   zdtStart plusDays  1      Currently the java time framework lacks an Interval class as described below for Joda-Time  However  the ThreeTen-Extra project extends java time with additional classes  This project is the proving ground for possible future additions to java time  Among its classes is Interval  Construct an Interval by passing a pair of Instant objects  We can extract an Instant from our ZonedDateTime objects  Interval today   Interval of  zdtStart toInstant     zdtTomorrowStart toInstant        About java time The java time framework is built into Java 8 and later  These classes supplant the troublesome old legacy date-time classes such as java util Date  Calendar   amp  SimpleDateFormat  To learn more  see the Oracle Tutorial  And search Stack Overflow for many examples and explanations  Specification is JSR 310  The Joda-Time project  now in maintenance mode  advises migration to the java time classes  You may exchange java time objects directly with your database  Use a JDBC driver compliant with JDBC 4 2 or later  No need for strings  no need for java sql   classes  Hibernate 5  amp  JPA 2 2 support java time  Where to obtain the java time classes   Java SE 8  Java SE 9  Java SE 10  Java SE 11  and later  - Part of the standard Java API with a bundled implementation   Java 9 brought some minor features and fixes    Java SE 6 and Java SE 7  Most of the java time functionality is back-ported to Java 6  amp  7 in ThreeTen-Backport    Android  Later versions of Android  26   bundle implementations of the java time classes  For earlier Android   lt 26   a process known as API desugaring brings a subset of the java time functionality not originally built into Android   If the desugaring does not offer what you need  the ThreeTenABP project adapts ThreeTen-Backport  mentioned above  to Android  See How to use ThreeTenABP           Joda-Time UPDATE  The Joda-Time project is now in maintenance-mode  and advises migration to the java time classes  I am leaving this section intact for history  Joda-Time has three classes to represent a span of time in various ways  Interval  Period  and Duration  An Interval has a specific beginning and ending on the timeline of the Universe  This fits our need to represent  quot a day quot   We call the method withTimeAtStartOfDay rather than set time of day to zeros  Because of Daylight Saving Time and other anomalies the first moment of the day may not be 00 00 00  Example code using Joda-Time 2 3  DateTimeZone timeZone   DateTimeZone forID   quot America Montreal quot     DateTime now   DateTime now  timeZone    DateTime todayStart   now withTimeAtStartOfDay    DateTime tomorrowStart   now plusDays  1   withTimeAtStartOfDay    Interval today   new Interval  todayStart  tomorrowStart     If you must  you can convert to a java util Date  java util Date date   todayStart toDate

User · Answer

in getEndOfDay  you can add   calendar set Calendar MILLISECOND  999     Although mathematically speaking  you can t specify the end of a day other than by saying it s  before the beginning of the next day     So instead of saying  if date  gt   getStartOfDay today   amp  amp  date  lt   getEndOfDay today    you should say  if date  gt   getStartOfDay today   amp  amp  date  lt  getStartOfDay tomorrow    That is a much more solid definition  and you don t have to worry about millisecond precision

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Additional way of finding start of day with java8 java time ZonedDateTime instead of going through LocalDateTime is simply truncating the input ZonedDateTime to DAYS   zonedDateTimeInstance truncatedTo  ChronoUnit DAYS

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Java 8    public static Date atStartOfDay Date date        LocalDateTime localDateTime   dateToLocalDateTime date       LocalDateTime startOfDay   localDateTime with LocalTime MIN       return localDateTimeToDate startOfDay      public static Date atEndOfDay Date date        LocalDateTime localDateTime   dateToLocalDateTime date       LocalDateTime endOfDay   localDateTime with LocalTime MAX       return localDateTimeToDate endOfDay      private static LocalDateTime dateToLocalDateTime Date date        return LocalDateTime ofInstant date toInstant    ZoneId systemDefault        private static Date localDateTimeToDate LocalDateTime localDateTime        return Date from localDateTime atZone ZoneId systemDefault    toInstant         Update  I ve added these 2 methods to my Java Utility Classes here   DateUtils atStartOfDay DateUtils atEndOfDay   It is in the Maven Central Repository at    lt dependency gt     lt groupId gt com github rkumsher lt  groupId gt     lt artifactId gt utils lt  artifactId gt     lt version gt 1 3 lt  version gt   lt  dependency gt    Java 7 and Earlier    With Apache Commons  public static Date atEndOfDay Date date        return DateUtils addMilliseconds DateUtils ceiling date  Calendar DATE   -1      public static Date atStartOfDay Date date        return DateUtils truncate date  Calendar DATE       Without Apache Commons  public Date atEndOfDay Date date        Calendar calendar   Calendar getInstance        calendar setTime date       calendar set Calendar HOUR OF DAY  23       calendar set Calendar MINUTE  59       calendar set Calendar SECOND  59       calendar set Calendar MILLISECOND  999       return calendar getTime       public Date atStartOfDay Date date        Calendar calendar   Calendar getInstance        calendar setTime date       calendar set Calendar HOUR OF DAY  0       calendar set Calendar MINUTE  0       calendar set Calendar SECOND  0       calendar set Calendar MILLISECOND  0       return calendar getTime

User · Answer

For java 8 the following single line statements are working  In this example I use UTC timezone  Please consider to change TimeZone that you currently used   System out println new Date      final LocalDateTime endOfDay         LocalDateTime of LocalDate now    LocalTime MAX   final Date          endOfDayAsDate   Date from endOfDay toInstant ZoneOffset UTC     System out println endOfDayAsDate    final LocalDateTime startOfDay         LocalDateTime of LocalDate now    LocalTime MIN   final Date          startOfDayAsDate   Date from startOfDay toInstant ZoneOffset UTC     System out println startOfDayAsDate     If no time difference with output  Try  ZoneOffset ofHours 0

User · Answer

I tried this code and it works well   final ZonedDateTime now   ZonedDateTime now ZoneOffset UTC   final ZonedDateTime startofDay       now toLocalDate   atStartOfDay ZoneOffset UTC   final ZonedDateTime endOfDay       now toLocalDate   atTime LocalTime MAX  atZone ZoneOffset UTC

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java time  Using java time framework built into Java 8   import java time LocalTime  import java time LocalDateTime   LocalDateTime now   LocalDateTime now       2015-11-19T19 42 19 224    start of a day now with LocalTime MIN      2015-11-19T00 00 now with LocalTime MIDNIGHT      2015-11-19T00 00    end of a day now with LocalTime MAX      2015-11-19T23 59 59 999999999

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Java 8 or ThreeTenABP  ZonedDateTime  ZonedDateTime curDate   ZonedDateTime now     public ZonedDateTime startOfDay         return curDate      toLocalDate        atStartOfDay        atZone curDate getZone         withEarlierOffsetAtOverlap       public ZonedDateTime endOfDay          ZonedDateTime startOfTomorrow           curDate          toLocalDate            plusDays 1           atStartOfDay            atZone curDate getZone             withEarlierOffsetAtOverlap         return startOfTomorrow minusSeconds 1         based on https   stackoverflow com a 29145886 1658268   LocalDateTime  LocalDateTime curDate   LocalDateTime now     public LocalDateTime startOfDay         return curDate atStartOfDay       public LocalDateTime endOfDay         return startOfTomorrow atTime LocalTime MAX      23 59 59 999999999        based on https   stackoverflow com a 36408726 1658268   I hope that helps someone

User · Answer

public static Date beginOfDay Date date        Calendar cal   Calendar getInstance        cal setTime date       cal set Calendar HOUR OF DAY  0       cal set Calendar MINUTE  0       cal set Calendar SECOND  0       cal set Calendar MILLISECOND  0        return cal getTime       public static Date endOfDay Date date        Calendar cal   Calendar getInstance        cal setTime date       cal set Calendar HOUR OF DAY  23       cal set Calendar MINUTE  59       cal set Calendar SECOND  59       cal set Calendar MILLISECOND  999        return cal getTime

[java] How to obtain the start time and end time of a day?

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