Date in to UTC format Java

Question

I have a string like this 2013-10-22T01 37 56  I Need to change this string into UTC Date format like this MM dd yyyy KK mm ss a  I have tried some code but it is not returning the UTC datetime   My code is          String   time   itsAlarmDttm split  T            String aFormatDate   time 0       time 1           String aRevisedDate   null          try               final SimpleDateFormat sdf   new SimpleDateFormat  yyyy-MM-dd HH mm ss                final Date dateObj   sdf parse aFormatDate               aRevisedDate   new SimpleDateFormat  MM dd yyyy KK mm ss a   format dateObj               System out println aRevisedDate             catch  ParseException e                itsLogger error  Error occured in Parsing the Data Time Object      e getMessage               catch  Exception e                itsLogger error  Error occured in Data Time Objecct      e getMessage                 I am getting the output is MM dd yyyy KK mm ss a format  But Not UTC time format  How to solve this issue

User · Answer

java time  It   s about time someone provides the modern answer  The modern solution uses java time  the modern Java date and time API  The classes SimpleDateFormat and Date used in the question and in a couple of the other answers are poorly designed and long outdated  the former in particular notoriously troublesome  TimeZone is poorly designed to  I recommend you avoid those       ZoneId utc   ZoneId of  Etc UTC        DateTimeFormatter targetFormatter   DateTimeFormatter ofPattern               MM dd yyyy hh mm ss a zzz   Locale ENGLISH        String itsAlarmDttm    2013-10-22T01 37 56       ZonedDateTime utcDateTime   LocalDateTime parse itsAlarmDttm               atZone ZoneId systemDefault                 withZoneSameInstant utc       String formatterUtcDateTime   utcDateTime format targetFormatter       System out println formatterUtcDateTime     When running in my time zone  Europe Copenhagen  the output is      10 21 2013 11 37 56 PM UTC   I have assumed that the string you got was in the default time zone of your JVM  a fragile assumption since that default setting can be changed at any time from another part of your program or another programming running in the same JVM  If you can  instead specify time zone explicitly  for example ZoneId of  Europe Podgorica   or ZoneId of  Asia Kolkata     I am exploiting the fact that you string is in ISO 8601 format  the format the the modern classes parse as their default  that is  without any explicit formatter   I am using a ZonedDateTime for the result date-time because it allows us to format it with UTC in the formatted string to eliminate any and all doubt  For other purposes one would typically have wanted an OffsetDateTime or an Instant instead   Links   Oracle tutorial  Date Time explaining how to use java time  Wikipedia article  ISO 8601

User · Answer

What Time Zones  No where in your question do you mention time zone  What time zone is implied that input string  What time zone do you want for your output  And  UTC is a time zone  or lack thereof depending on your mindset  not a string format  ISO 8601 Your input string is in ISO 8601 format  except that it lacks an offset from UTC  Joda-Time Here is some example code in Joda-Time 2 3 to show you how to handle time zones  Joda-Time has built-in default formatters for parsing and generating String representations of date-time values  String input    quot 2013-10-22T01 37 56 quot   DateTime dateTimeUtc   new DateTime  input  DateTimeZone UTC    DateTime dateTimeMontr  al   dateTimeUtc withZone  DateTimeZone forID   quot America Montreal quot     String output   dateTimeMontr  al toString     As for generating string representations in other formats  search StackOverflow for  quot Joda format quot

User · Answer

Try this    Worked for me and printed 10 22 2013 01 37 56 AM Ofcourse this is your code only with little modifications   final SimpleDateFormat sdf   new SimpleDateFormat  yyyy-MM-dd T HH mm ss    sdf setTimeZone TimeZone getTimeZone  UTC          This line converts the given date into UTC time zone final java util Date dateObj   sdf parse  2013-10-22T01 37 56     aRevisedDate   new SimpleDateFormat  MM dd yyyy KK mm ss a   format dateObj   System out println aRevisedDate

User · Answer

Try to format your date with the Z or z timezone flags   new SimpleDateFormat  MM dd yyyy KK mm ss a Z   format dateObj

User · Answer

SimpleDateFormat sdf   new SimpleDateFormat   yyyy-MM-dd HH mm ss        or SimpleDateFormat sdf   new SimpleDateFormat   MM dd yyyy KK mm ss a Z     sdf setTimeZone  TimeZone getTimeZone   UTC       System out println  sdf format  new Date

[java] Date in to UTC format Java

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