[java] Java string to date conversion

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.

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 -> "+mydate);
System.out.println("year   -> "+mydate.get(Calendar.YEAR));
System.out.println("month  -> "+mydate.get(Calendar.MONTH));
System.out.println("dom    -> "+mydate.get(Calendar.DAY_OF_MONTH));
System.out.println("dow    -> "+mydate.get(Calendar.DAY_OF_WEEK));
System.out.println("hour   -> "+mydate.get(Calendar.HOUR));
System.out.println("minute -> "+mydate.get(Calendar.MINUTE));
System.out.println("second -> "+mydate.get(Calendar.SECOND));
System.out.println("milli  -> "+mydate.get(Calendar.MILLISECOND));
System.out.println("ampm   -> "+mydate.get(Calendar.AM_PM));
System.out.println("hod    -> "+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 -> "+mydate);
System.out.println("year   -> "+mydate.get(Calendar.YEAR));
System.out.println("month  -> "+mydate.get(Calendar.MONTH));
System.out.println("dom    -> "+mydate.get(Calendar.DAY_OF_MONTH));
System.out.println("dow    -> "+mydate.get(Calendar.DAY_OF_WEEK));
System.out.println("hour   -> "+mydate.get(Calendar.HOUR));
System.out.println("minute -> "+mydate.get(Calendar.MINUTE));
System.out.println("second -> "+mydate.get(Calendar.SECOND));
System.out.println("milli  -> "+mydate.get(Calendar.MILLISECOND));
System.out.println("ampm   -> "+mydate.get(Calendar.AM_PM));
System.out.println("hod    -> "+mydate.get(Calendar.HOUR_OF_DAY));

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);

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.

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);

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<Long> longs = new ArrayList<>();
        List<String> strings = new ArrayList<>();

        //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

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

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;
        }

DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
  Date date1 = null;
  Date date2 = null;

  try {
    date1 = dateFormat.parse(t1);
    date2 = dateFormat.parse(t2);
  } catch (ParseException e) {
    e.printStackTrace();
  }
  DateFormat formatter = new SimpleDateFormat("dd-MMM-yyyy");
  String StDate = formatter.format(date1);
  String edDate = formatter.format(date2);

  System.out.println("ST  "+ StDate);
  System.out.println("ED "+ edDate);

Simple two formatters we have used:

1. Which format date do we want?
2. 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));
}

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.

You can use SimpleDateformat for change string to date

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String strDate = "2000-01-01";
Date date = sdf.parse(strDate);

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;

SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yyyy");
return sdf.format(date);

SimpleDateFormat sdf = new SimpleDateFormat(datePattern); 
return sdf.parse(dateStr);

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat newSdf = new SimpleDateFormat("dd-MM-yyyy");
Date temp = sdf.parse(dateStr);
return newSdf.format(temp);

Source link.

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.

String str_date = "11-June-07";
DateFormat formatter;
Date date;
formatter = new SimpleDateFormat("dd-MMM-yy");
date = formatter.parse(str_date);