Convert Java Date to UTC String

Question

The java util Date toString   method displays the date in the local time zone  There are several common scenarios where we want the data to be printed in UTC  including logs  data export and communication with external programs   What s the best way to create a String representation of java util Date in UTC  How to replace the j u Date   s toString   format  which isn t sortable  thanks   JonSkeet   with a better format   Addendum I think that the standard way of printing the date in a custom format and time zone is quite tedious  final Date date   new Date    final String ISO FORMAT    quot yyyy-MM-dd T HH mm ss SSS zzz quot   final SimpleDateFormat sdf   new SimpleDateFormat ISO FORMAT   final TimeZone utc   TimeZone getTimeZone  quot UTC quot    sdf setTimeZone utc   System out println sdf format date     I was looking for a one-liner like  System out println prettyPrint date   quot yyyy-MM-dd T HH mm ss SSS zzz quot    quot UTC quot

User · Answer

Why not just use java text SimpleDateFormat    Date someDate   new Date    SimpleDateFormat df   new SimpleDateFormat  yyyy-MM-dd    String s   df format someDate     Or see  http   www tutorialspoint com java java date time htm

User · Answer

If XStream is a dependency  try   new com thoughtworks xstream converters basic DateConverter   toString date

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java time Instant  Just use Instant of java time       System out println Instant now       This just printed   2018-01-27T09 35 23 179612Z   Instant toString always gives UTC time   The output is usually sortable  but there are unfortunate exceptions  toString gives you enough groups of three decimals to render the precision it holds  On the Java 9 on my Mac the precision of Instant now   seems to be microseconds  but we should expect that in approximately one case out of a thousand it will hit a whole number of milliseconds and print only three decimals  Strings with unequal numbers of decimals will be sorted in the wrong order  unless you write a custom comparator to take this into account    Instant is one of the classes in java time  the modern Java date and time API  which I warmly recommend that you use instead of the outdated Date class  java time is built into Java 8 and later and has also been backported to Java 6 and 7

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Following the useful comments  I ve completely rebuilt the date formatter  Usage is supposed to    Be short  one liner  Represent disposable objects  time zone  format  as Strings Support useful  sortable ISO formats and the legacy format from the box   If you consider this code useful  I may publish the source and a JAR in github   Usage     The problem - not UTC Date toString                          Tue Jul 03 14 54 24 IDT 2012      ISO format  now PrettyDate now            2012-07-03T11 54 24 256 UTC      ISO format  specific date PrettyDate toString new Date              2012-07-03T11 54 24 256 UTC      Legacy format  specific date PrettyDate toLegacyString new Date        Tue Jul 03 11 54 24 UTC 2012      ISO  specific date and time zone PrettyDate toString moonLandingDate   yyyy-MM-dd hh mm ss zzz    CST     1969-07-20 03 17 40 CDT      Specific format and date PrettyDate toString moonLandingDate   yyyy-MM-dd    1969-07-20      ISO  specific date PrettyDate toString moonLandingDate   1969-07-20T20 17 40 234 UTC      Legacy  specific date PrettyDate toLegacyString moonLandingDate   Wed Jul 20 08 17 40 UTC 1969    Code   This code is also the subject of a question on Code Review stackexchange   import java text SimpleDateFormat  import java util Date  import java util TimeZone          Formats dates to sortable UTC strings in compliance with ISO-8601          author Adam Matan  lt adam matan name gt      see http   stackoverflow com questions 11294307 convert-java-date-to-utc-string 11294308     public class PrettyDate       public static String ISO FORMAT    yyyy-MM-dd T HH mm ss SSS zzz       public static String LEGACY FORMAT    EEE MMM dd hh mm ss zzz yyyy       private static final TimeZone utc   TimeZone getTimeZone  UTC        private static final SimpleDateFormat legacyFormatter   new SimpleDateFormat LEGACY FORMAT       private static final SimpleDateFormat isoFormatter   new SimpleDateFormat ISO FORMAT       static           legacyFormatter setTimeZone utc           isoFormatter setTimeZone utc                         Formats the current time in a sortable ISO-8601 UTC format                  return Current time in ISO-8601 format  e g                    2012-07-03T07 59 09 206 UTC              public static String now             return PrettyDate toString new Date                           Formats a given date in a sortable ISO-8601 UTC format                  lt pre gt          lt code gt         final Calendar moonLandingCalendar   Calendar getInstance TimeZone getTimeZone  UTC            moonLandingCalendar set 1969  7  20  20  18  0          final Date moonLandingDate   moonLandingCalendar getTime           System out println  UTCDate toString moon            PrettyDate toString moonLandingDate            gt  gt  gt  UTCDate toString moon        1969-08-20T20 18 00 209 UTC         lt  code gt          lt  pre gt                  param date                   Valid Date object          return The given date in ISO-8601 format                       public static String toString final Date date            return isoFormatter format date                         Formats a given date in the standard Java Date toString    using UTC        instead of locale time zone                  lt pre gt          lt code gt         System out println UTCDate toLegacyString new Date              gt  gt  gt   Tue Jul 03 07 33 57 UTC 2012          lt  code gt          lt  pre gt                  param date                   Valid Date object          return The given date in Legacy Date toString   format  e g                  Tue Jul 03 09 34 17 IDT 2012              public static String toLegacyString final Date date            return legacyFormatter format date                         Formats a date in any given format at UTC                  lt pre gt          lt code gt         final Calendar moonLandingCalendar   Calendar getInstance TimeZone getTimeZone  UTC            moonLandingCalendar set 1969  7  20  20  17  40          final Date moonLandingDate   moonLandingCalendar getTime           PrettyDate toString moonLandingDate   yyyy-MM-dd           gt  gt  gt   1969-08-20          lt  code gt          lt  pre gt                          param date                   Valid Date object          param format                   String representation of the format  e g   yyyy-MM-dd          return The given date formatted in the given format              public static String toString final Date date  final String format            return toString date  format   UTC                          Formats a date at any given format String  at any given Timezone String                          param date                   Valid Date object         param format                   String representation of the format  e g   yyyy-MM-dd HH mm          param timezone                   String representation of the time zone  e g   CST          return The formatted date in the given time zone              public static String toString final Date date  final String format  final String timezone            final TimeZone tz   TimeZone getTimeZone timezone           final SimpleDateFormat formatter   new SimpleDateFormat format           formatter setTimeZone tz           return formatter format date

User · Answer

tl dr  You asked      I was looking for a one-liner like    Ask and ye shall receive  Convert from terrible legacy class Date to its modern replacement  Instant    myJavaUtilDate toInstant   toString        2020-05-05T19 46 12 912Z   java time  In Java 8 and later we have the new java time package built in  Tutorial   Inspired by Joda-Time  defined by JSR 310  and extended by the ThreeTen-Extra project   The best solution is to sort your date-time objects rather than strings  But if you must work in strings  read on   An Instant represents a moment on the timeline  basically in UTC  see class doc for precise details   The toString implementation uses the DateTimeFormatter ISO INSTANT format by default  This format includes zero  three  six or nine digits digits as needed to display fraction of a second up to nanosecond precision    String output   Instant now   toString       Example   2015-12-03T10 15 30 120Z    If you must interoperate with the old Date class  convert to from java time via new methods added to the old classes  Example  Date  toInstant   myJavaUtilDate toInstant   toString     You may want to use an alternate formatter if you need a consistent number of digits in the fractional second or if you need no fractional second   Another route if you want to truncate fractions of a second is to use ZonedDateTime instead of Instant  calling its method to change the fraction to zero    Note that we must specify a time zone for ZonedDateTime  thus the name   In our case that means UTC  The subclass of ZoneID  ZoneOffset  holds a convenient constant for UTC  If we omit the time zone  the JVM   s current default time zone is implicitly applied   String output   ZonedDateTime now  ZoneOffset UTC   withNano  0   toString        Example  2015-08-27T19 28 58Z         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 adds 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 bundle implementations of the java time classes  For earlier Android   lt 26   the ThreeTenABP project adapts ThreeTen-Backport  mentioned above   See How to use ThreeTenABP          Joda-Time  UPDATE  The Joda -Time project is now in maintenance mode  with the team advising migration to the java time classes        I was looking for a one-liner   Easy if using the Joda-Time 2 3 library  ISO 8601 is the default formatting   Time Zone  In the code example below  note that I am specifying a time zone rather than depending on the default time zone  In this case  I m specifying UTC per your question  The Z on the end  spoken as  Zulu   means no time zone offset from UTC   Example Code     import org joda time     String output   new DateTime  DateTimeZone UTC      Output     2013-12-12T18 29 50 588Z

User · Answer

The following simplified code  based on the accepted answer above  worked for me   public class GetSync       public static String ISO FORMAT    yyyy-MM-dd T HH mm ss SSS zzz       private static final TimeZone utc   TimeZone getTimeZone  UTC        private static final SimpleDateFormat isoFormatter   new SimpleDateFormat ISO FORMAT       static           isoFormatter setTimeZone utc              public static String now             return isoFormatter format new Date    toString              I hope this helps somebody

User · Answer

Well if you want to use java util Date only  here is a small trick you can use   String dateString   Long toString Date UTC date getYear    date getMonth    date getDate    date getHours    date getMinutes    date getSeconds

[java] Convert Java Date to UTC String

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