Java string to date conversion

Question

What is the best way to convert a String in the format  January 2  2010  to a Date in Java   Ultimately  I want to break out the month  the day  and the year as integers so that I can use  Date date   new Date    date setMonth     date setYear     date setDay     date setlong currentTime   date getTime      to convert the date into time

User · Answer

While some of the answers are technically correct, they are not advisable.

The java.util.Date & Calendar classes are notoriously troublesome. Because of flaws in design and implementation, avoid them. Fortunately we have our choice of two other excellent date-time libraries:
- Joda-Time
  This popular open-source free-of-cost library can be used across several versions of Java. Many examples of its usage may be found on StackOverflow. Reading some of these will help get you up to speed quickly.
- java.time.* package
  This new set of classes are inspired by Joda-Time and defined by JSR 310. These classes are built into Java 8. A project is underway to backport these classes to Java 7, but that backporting is not backed by Oracle.
As Kristopher Johnson correctly noted in his comment on the question, the other answers ignore vital issues of:
- Time of Day
  Date has both a date portion and a time-of-day portion)
- Time Zone
  The beginning of a day depends on the time zone. If you fail to specify a time zone, the JVM's default time zone is applied. That means the behavior of your code may change when run on other computers or with a modified time zone setting. Probably not what you want.
- Locale
  The Locale's language specifies how to interpret the words (name of month and of day) encountered during parsing. (The answer by BalusC handles this properly.) Also, the Locale affects the output of some formatters when generating a string representation of your date-time.

Joda-Time

A few notes about Joda-Time follow.

Time Zone

In Joda-Time, a DateTime object truly knows its own assigned time zone. This contrasts the java.util.Date class which seems to have a time zone but does not.

Note in the example code below how we pass a time zone object to the formatter which parses the string. That time zone is used to interpret that date-time as having occurred in that time zone. So you need to think about and determine the time zone represented by that string input.

Since you have no time portion in your input string, Joda-Time assigns the first moment of the day of the specified time zone as the time-of-day. Usually this means 00:00:00 but not always, because of Daylight Saving Time (DST) or other anomalies. By the way, you can do the same to any DateTime instance by calling withTimeAtStartOfDay.

Formatter Pattern

The characters used in a formatter's pattern are similar in Joda-Time to those in java.util.Date/Calendar but not exactly the same. Carefully read the doc.

Immutability

We usually use the immutable classes in Joda-Time. Rather than modify an existing Date-Time object, we call methods that create a new fresh instance based on the other object with most aspects copied except where alterations were desired. An example is the call to withZone in last line below. Immutability helps to make Joda-Time very thread-safe, and can also make some work more clear.

Conversion

You will need java.util.Date objects for use with other classes/framework that do not know about Joda-Time objects. Fortunately, it is very easy to move back and forth.

Going from a java.util.Date object (here named date) to Joda-Time DateTime…

org.joda.time.DateTime dateTime = new DateTime( date, timeZone );

Going the other direction from Joda-Time to a java.util.Date object…

java.util.Date date = dateTime.toDate();

Sample Code

String input = "January 2, 2010";

java.util.Locale locale = java.util.Locale.US;
DateTimeZone timeZone = DateTimeZone.forID( "Pacific/Honolulu" ); // Arbitrarily chosen for example.
DateTimeFormatter formatter = DateTimeFormat.forPattern( "MMMM d, yyyy" ).withZone( timeZone ).withLocale( locale );
DateTime dateTime = formatter.parseDateTime( input );

System.out.println( "dateTime: " + dateTime );
System.out.println( "dateTime in UTC/GMT: " + dateTime.withZone( DateTimeZone.UTC ) );

When run…

dateTime: 2010-01-02T00:00:00.000-10:00
dateTime in UTC/GMT: 2010-01-02T10:00:00.000Z

User · Answer

Simple two formatters we have used    Which format date do we want  Which format date is actually present    We parse the full date to time format   date  2016-05-06 16 40 32    public static String setDateParsing String date  throws ParseException           This is the format date we want     DateFormat mSDF   new SimpleDateFormat  hh mm a            This format date is actually present     SimpleDateFormat formatter   new SimpleDateFormat  yyyy-mm-dd hh mm        return mSDF format formatter parse date

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From Date to String SimpleDateFormat sdf   new SimpleDateFormat  quot dd-MM-yyyy quot    return sdf format date    From String to Date SimpleDateFormat sdf   new SimpleDateFormat datePattern    return sdf parse dateStr    From date String to different format SimpleDateFormat sdf   new SimpleDateFormat  quot yyyy-MM-dd quot    SimpleDateFormat newSdf   new SimpleDateFormat  quot dd-MM-yyyy quot    Date temp   sdf parse dateStr   return newSdf format temp    Source link

User · Answer

Also  SimpleDateFormat is not available with some of the client-side technologies  like GWT   It s a good idea to go for Calendar getInstance    and your requirement is to compare two dates  go for long date

User · Answer

Try this  String date   get pump data getString  bond end date    DateFormat format   new SimpleDateFormat  yyyy-MM-dd   Locale ENGLISH   Date datee    Date format parse date

User · Answer

With Java 8 we get a new Date   Time API  JSR 310    The following way can be used to parse the date in Java 8 without relying on Joda-Time    String str    January 2nd  2010          if we 2nd even we have changed in pattern also it is not working please workout with 2nd  DateTimeFormatter formatter   DateTimeFormatter ofPattern  MMMM Q  yyyy   Locale ENGLISH   LocalDate date   LocalDate parse str  formatter          access date fields int year   date getYear       2010 int day   date getDayOfMonth       2 Month month   date getMonth       JANUARY int monthAsInt   month getValue       1     LocalDate is the standard Java 8 class for representing a date  without time   If you want to parse values that contain date and time information you should use LocalDateTime  For values with timezones use ZonedDateTime  Both provide a parse   method similar to LocalDate   LocalDateTime dateWithTime   LocalDateTime parse strWithDateAndTime  dateTimeFormatter   ZonedDateTime zoned   ZonedDateTime parse strWithTimeZone  zoneFormatter     The list formatting characters from DateTimeFormatter Javadoc   All letters  A  to  Z  and  a  to  z  are reserved as pattern letters   The following pattern letters are defined   Symbol  Meaning                     Presentation      Examples ------  -------                     ------------      -------  G       era                         text              AD  Anno Domini  A  u       year                        year              2004  04  y       year-of-era                 year              2004  04  D       day-of-year                 number            189  M L     month-of-year               number text       7  07  Jul  July  J  d       day-of-month                number            10   Q q     quarter-of-year             number text       3  03  Q3  3rd quarter  Y       week-based-year             year              1996  96  w       week-of-week-based-year     number            27  W       week-of-month               number            4  E       day-of-week                 text              Tue  Tuesday  T  e c     localized day-of-week       number text       2  02  Tue  Tuesday  T  F       week-of-month               number            3   a       am-pm-of-day                text              PM  h       clock-hour-of-am-pm  1-12   number            12  K       hour-of-am-pm  0-11         number            0  k       clock-hour-of-am-pm  1-24   number            0   H       hour-of-day  0-23           number            0  m       minute-of-hour              number            30  s       second-of-minute            number            55  S       fraction-of-second          fraction          978  A       milli-of-day                number            1234  n       nano-of-second              number            987654321  N       nano-of-day                 number            1234000000   V       time-zone ID                zone-id           America Los Angeles  Z  -08 30  z       time-zone name              zone-name         Pacific Standard Time  PST  O       localized zone-offset       offset-O          GMT 8  GMT 08 00  UTC-08 00   X       zone-offset  Z  for zero    offset-X          Z  -08  -0830  -08 30  -083015  -08 30 15   x       zone-offset                 offset-x           0000  -08  -0830  -08 30  -083015  -08 30 15   Z       zone-offset                 offset-Z           0000  -0800  -08 00

User · Answer

My humble test program  I use it to play around with the formatter and look-up long dates that I find in log-files  but who has put them there       My test program   package be test package time   import java text DateFormat  import java text ParseException  import java text SimpleDateFormat  import java util ArrayList  import java util Date  import java util List  import java util TimeZone   public class TimeWork        public static void main String   args                 TimeZone timezone   TimeZone getTimeZone  UTC             List lt Long gt  longs   new ArrayList lt  gt             List lt String gt  strings   new ArrayList lt  gt                Formatting a date needs a timezone - otherwise the date get formatted to your system time zone            Use 24h format HH  In 12h format hh can be in range 0-11  which makes 12 overflow to 0          DateFormat formatter   new SimpleDateFormat  dd-MM-yyyy HH mm ss SSS            formatter setTimeZone timezone            Date now   new Date               Test dates         strings add formatter format now            strings add  01-01-1970 00 00 00 000            strings add  01-01-1970 00 00 01 000            strings add  01-01-1970 00 01 00 000            strings add  01-01-1970 01 00 00 000            strings add  01-01-1970 10 00 00 000            strings add  01-01-1970 12 00 00 000            strings add  01-01-1970 24 00 00 000            strings add  02-01-1970 00 00 00 000            strings add  01-01-1971 00 00 00 000            strings add  01-01-2014 00 00 00 000            strings add  31-12-1969 23 59 59 000            strings add  31-12-1969 23 59 00 000            strings add  31-12-1969 23 00 00 000               Test data         longs add now getTime             longs add -1L           longs add 0L     Long date presentation at - midnight 1 1 1970 UTC - The timezone is important          longs add 1L           longs add 1000L           longs add 60000L           longs add 3600000L           longs add 36000000L           longs add 43200000L           longs add 86400000L           longs add 31536000000L           longs add 1388534400000L           longs add 7260000L           longs add 1417706084037L           longs add -7260000L            System out println        String to long                     Show the long value of the date         for  String string  strings                try                   Date date   formatter parse string                   System out println  Formated date       string       Long       date getTime                   catch  ParseException e                    e printStackTrace                                     System out println        Long to String                     Show the date behind the long         for  Long lo   longs                Date date   new Date lo               String string   formatter format date               System out println  Formated date       string       Long       lo                               Test results         String to long       Formated date   05-12-2014 10 17 34 873   Long   1417774654873 Formated date   01-01-1970 00 00 00 000   Long   0 Formated date   01-01-1970 00 00 01 000   Long   1000 Formated date   01-01-1970 00 01 00 000   Long   60000 Formated date   01-01-1970 01 00 00 000   Long   3600000 Formated date   01-01-1970 10 00 00 000   Long   36000000 Formated date   01-01-1970 12 00 00 000   Long   43200000 Formated date   01-01-1970 24 00 00 000   Long   86400000 Formated date   02-01-1970 00 00 00 000   Long   86400000 Formated date   01-01-1971 00 00 00 000   Long   31536000000 Formated date   01-01-2014 00 00 00 000   Long   1388534400000 Formated date   31-12-1969 23 59 59 000   Long   -1000 Formated date   31-12-1969 23 59 00 000   Long   -60000 Formated date   31-12-1969 23 00 00 000   Long   -3600000       Long to String       Formated date   05-12-2014 10 17 34 873   Long   1417774654873 Formated date   31-12-1969 23 59 59 999   Long   -1 Formated date   01-01-1970 00 00 00 000   Long   0 Formated date   01-01-1970 00 00 00 001   Long   1 Formated date   01-01-1970 00 00 01 000   Long   1000 Formated date   01-01-1970 00 01 00 000   Long   60000 Formated date   01-01-1970 01 00 00 000   Long   3600000 Formated date   01-01-1970 10 00 00 000   Long   36000000 Formated date   01-01-1970 12 00 00 000   Long   43200000 Formated date   02-01-1970 00 00 00 000   Long   86400000 Formated date   01-01-1971 00 00 00 000   Long   31536000000 Formated date   01-01-2014 00 00 00 000   Long   1388534400000 Formated date   01-01-1970 02 01 00 000   Long   7260000 Formated date   04-12-2014 15 14 44 037   Long   1417706084037 Formated date   31-12-1969 21 59 00 000   Long   -7260000

User · Answer

DateFormat dateFormat   new SimpleDateFormat  yyyy-MM-dd    Date date  try       date   dateFormat parse  2013-12-4        System out println date toString        Wed Dec 04 00 00 00 CST 2013      String output   dateFormat format date       System out println output      2013-12-04    catch  ParseException e        e printStackTrace        It works fine for me

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Source Link  For Android   Calendar getInstance   getTime   gives   Thu Jul 26 15 54 13 GMT 05 30 2018   Use  String oldDate    Thu Jul 26 15 54 13 GMT 05 30 2018   DateFormat format   new SimpleDateFormat  EEE LLL dd HH mm ss Z yyyy    Date updateLast   format parse oldDate

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DateFormat dateFormat   new SimpleDateFormat  quot yyyy-MM-dd T HH mm ss quot      Date date1   null    Date date2   null     try       date1   dateFormat parse t1       date2   dateFormat parse t2       catch  ParseException e        e printStackTrace          DateFormat formatter   new SimpleDateFormat  quot dd-MMM-yyyy quot      String StDate   formatter format date1     String edDate   formatter format date2      System out println  quot ST   quot   StDate     System out println  quot ED  quot   edDate

User · Answer

That s the hard way  and those java util Date setter methods have been deprecated since Java 1 1  1997   Simply format the date using SimpleDateFormat using a format pattern matching the input string  In your specific case of  quot January 2  2010 quot  as the input string    quot January quot  is the full text month  so use the MMMM pattern for it  quot 2 quot  is the short day-of-month  so use the d pattern for it   quot 2010 quot  is the 4-digit year  so use the yyyy pattern for it    String string    quot January 2  2010 quot   DateFormat format   new SimpleDateFormat  quot MMMM d  yyyy quot   Locale ENGLISH   Date date   format parse string   System out println date      Sat Jan 02 00 00 00 GMT 2010  Note the importance of the explicit Locale argument  If you omit it  then it will use the default locale which is not necessarily English as used in the month name of the input string  If the locale doesn t match with the input string  then you would confusingly get a java text ParseException even though when the format pattern seems valid  Here s an extract of relevance from the javadoc  listing all available format patterns      Letter Date or Time Component Presentation Examples     G Era designator Text AD   y Year Year 1996  96   Y Week year Year 2009  09   M L Month in year Month July  Jul  07   w Week in year Number 27   W Week in month Number 2   D Day in year Number 189   d Day in month Number 10   F Day of week in month Number 2   E Day in week Text Tuesday  Tue   u Day number of week Number 1   a Am pm marker Text PM   H Hour in day  0-23  Number 0   k Hour in day  1-24  Number 24   K Hour in am pm  0-11  Number 0   h Hour in am pm  1-12  Number 12   m Minute in hour Number 30   s Second in minute Number 55   S Millisecond Number 978   z Time zone General time zone Pacific Standard Time  PST  GMT-08 00   Z Time zone RFC 822 time zone -0800   X Time zone ISO 8601 time zone -08  -0800  -08 00     Note that the patterns are case sensitive and that text based patterns of four characters or more represent the full form  otherwise a short or abbreviated form is used if available  So e g  MMMMM or more is unnecessary  Here are some examples of valid SimpleDateFormat patterns to parse a given string to date      Input string Pattern     2001 07 04 AD at 12 08 56 PDT yyyy MM dd G  at  HH mm ss z   Wed  Jul 4   01 EEE  MMM d    yy   12 08 PM h mm a   12 o clock PM  Pacific Daylight Time hh  o  clock  a  zzzz   0 08 PM  PDT K mm a  z   02001 July 04 AD 12 08 PM yyyyy MMMM dd GGG hh mm aaa   Wed  4 Jul 2001 12 08 56 -0700 EEE  d MMM yyyy HH mm ss Z   010704120856-0700 yyMMddHHmmssZ   2001-07-04T12 08 56 235-0700 yyyy-MM-dd T HH mm ss SSSZ   2001-07-04T12 08 56 235-07 00 yyyy-MM-dd T HH mm ss SSSXXX   2001-W27-3 YYYY- W ww-u     An important note is that SimpleDateFormat is not thread safe  In other words  you should never declare and assign it as a static or instance variable and then reuse it from different methods threads  You should always create it brand new within the method local scope   Java 8 update If you happen to be on Java 8 or newer  then use DateTimeFormatter  also here  click the link to see all predefined formatters and available format patterns  the tutorial is available here   This new API is inspired by JodaTime  String string    quot January 2  2010 quot   DateTimeFormatter formatter   DateTimeFormatter ofPattern  quot MMMM d  yyyy quot   Locale ENGLISH   LocalDate date   LocalDate parse string  formatter   System out println date      2010-01-02  Note  if your format pattern happens to contain the time part as well  then use LocalDateTime parse text  formatter  instead of LocalDate parse text  formatter   And  if your format pattern happens to contain the time zone as well  then use ZonedDateTime parse text  formatter  instead  Here s an extract of relevance from the javadoc  listing all available format patterns      Symbol Meaning Presentation Examples     G era text AD  Anno Domini  A   u year year 2004  04   y year-of-era year 2004  04   D day-of-year number 189   M L month-of-year number text 7  07  Jul  July  J   d day-of-month number 10   Q q quarter-of-year number text 3  03  Q3  3rd quarter   Y week-based-year year 1996  96   w week-of-week-based-year number 27   W week-of-month number 4   E day-of-week text Tue  Tuesday  T   e c localized day-of-week number text 2  02  Tue  Tuesday  T   F week-of-month number 3   a am-pm-of-day text PM   h clock-hour-of-am-pm  1-12  number 12   K hour-of-am-pm  0-11  number 0   k clock-hour-of-am-pm  1-24  number 0   H hour-of-day  0-23  number 0   m minute-of-hour number 30   s second-of-minute number 55   S fraction-of-second fraction 978   A milli-of-day number 1234   n nano-of-second number 987654321   N nano-of-day number 1234000000   V time-zone ID zone-id America Los Angeles  Z  -08 30   z time-zone name zone-name Pacific Standard Time  PST   O localized zone-offset offset-O GMT 8  GMT 08 00  UTC-08 00    X zone-offset  Z  for zero offset-X Z  -08  -0830  -08 30  -083015  -08 30 15    x zone-offset offset-x  0000  -08  -0830  -08 30  -083015  -08 30 15    Z zone-offset offset-Z  0000  -0800  -08 00      Do note that it has several predefined formatters for the more popular patterns  So instead of e g  DateTimeFormatter ofPattern  quot EEE  d MMM yyyy HH mm ss Z quot   Locale ENGLISH    you could use DateTimeFormatter RFC 1123 DATE TIME  This is possible because they are  on the contrary to SimpleDateFormat  thread safe  You could thus also define your own  if necessary  For a particular input string format  you don t need to use an explicit DateTimeFormatter  a standard ISO 8601 date  like 2016-09-26T17 44 57Z  can be parsed directly with LocalDateTime parse text  as it already uses the ISO LOCAL DATE TIME formatter  Similarly  LocalDate parse text  parses an ISO date without the time component  see ISO LOCAL DATE   and ZonedDateTime parse text  parses an ISO date with an offset and time zone added  see ISO ZONED DATE TIME

User · Answer

While on dealing with the SimpleDateFormat class  it s important to remember that Date is not thread-safe and you can not share a single Date object with multiple threads   Also there is big difference between  m  and  M  where small case is used for minutes and capital case is used for month  The same with  d  and  D   This can cause subtle bugs which often get overlooked  See Javadoc or Guide to Convert String to Date in Java for more details

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String to Date conversion       private Date StringtoDate String date  throws Exception               SimpleDateFormat sdf1   new SimpleDateFormat  yyyy-MM-dd                java sql Date sqlDate   null              if   date isEmpty                       try                       java util Date normalDate   sdf1 parse date                       sqlDate   new java sql Date normalDate getTime                       catch  ParseException e                        throw new Exception  Not able to Parse the date   e                                               return sqlDate

User · Answer

Ah yes the Java Date discussion  again   To deal with date manipulation we use Date  Calendar  GregorianCalendar  and SimpleDateFormat   For example using your January date as input   Calendar mydate   new GregorianCalendar    String mystring    January 2  2010   Date thedate   new SimpleDateFormat  MMMM d  yyyy   Locale ENGLISH  parse mystring   mydate setTime thedate     breakdown System out println  mydate - gt    mydate   System out println  year   - gt    mydate get Calendar YEAR    System out println  month  - gt    mydate get Calendar MONTH    System out println  dom    - gt    mydate get Calendar DAY OF MONTH    System out println  dow    - gt    mydate get Calendar DAY OF WEEK    System out println  hour   - gt    mydate get Calendar HOUR    System out println  minute - gt    mydate get Calendar MINUTE    System out println  second - gt    mydate get Calendar SECOND    System out println  milli  - gt    mydate get Calendar MILLISECOND    System out println  ampm   - gt    mydate get Calendar AM PM    System out println  hod    - gt    mydate get Calendar HOUR OF DAY      Then you can manipulate that with something like   Calendar now   Calendar getInstance    mydate set Calendar YEAR 2009   mydate set Calendar MONTH Calendar FEBRUARY   mydate set Calendar DAY OF MONTH 25   mydate set Calendar HOUR OF DAY now get Calendar HOUR OF DAY    mydate set Calendar MINUTE now get Calendar MINUTE    mydate set Calendar SECOND now get Calendar SECOND       or with one statement   mydate set 2009  Calendar FEBRUARY  25  now get Calendar HOUR OF DAY   now get Calendar MINUTE   now get Calendar SECOND    System out println  mydate - gt    mydate   System out println  year   - gt    mydate get Calendar YEAR    System out println  month  - gt    mydate get Calendar MONTH    System out println  dom    - gt    mydate get Calendar DAY OF MONTH    System out println  dow    - gt    mydate get Calendar DAY OF WEEK    System out println  hour   - gt    mydate get Calendar HOUR    System out println  minute - gt    mydate get Calendar MINUTE    System out println  second - gt    mydate get Calendar SECOND    System out println  milli  - gt    mydate get Calendar MILLISECOND    System out println  ampm   - gt    mydate get Calendar AM PM    System out println  hod    - gt    mydate get Calendar HOUR OF DAY

User · Answer

You can use SimpleDateformat for  change string to date  x000D   x000D  SimpleDateFormat sdf   new SimpleDateFormat  yyyy-MM-dd    String strDate    2000-01-01   Date date   sdf parse strDate   x000D   x000D   x000D

User · Answer

String str date    11-June-07   DateFormat formatter  Date date  formatter   new SimpleDateFormat  dd-MMM-yy    date   formatter parse str date

[java] Java string to date conversion

Joda-Time

Time Zone

Formatter Pattern

Immutability

Conversion

Sample Code

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