625

What is the best way to convert a java.util.Date object to the new JDK 8/JSR-310 java.time.LocalDate?

Date input = new Date();
LocalDate date = ???
Improve this question
0

14 Answers 14

Reset to default
1002

Short answer

Date input = new Date();
LocalDate date = input.toInstant().atZone(ZoneId.systemDefault()).toLocalDate();

Java 9 answer

In Java SE 9, a new method has been added that slightly simplifies this task:

Date input = new Date();
LocalDate date = LocalDate.ofInstant(input.toInstant(), ZoneId.systemDefault());

This new alternative is more direct, creating less garbage, and thus should perform better.

Explanation

Despite its name, java.util.Date represents an instant on the time-line, not a "date". The actual data stored within the object is a long count of milliseconds since 1970-01-01T00:00Z (midnight at the start of 1970 GMT/UTC).

The equivalent class to java.util.Date in JSR-310 is Instant, thus there is a convenient method toInstant() to provide the conversion:

Date input = new Date();
Instant instant = input.toInstant();

A java.util.Date instance has no concept of time-zone. This might seem strange if you call toString() on a java.util.Date, because the toString is relative to a time-zone. However that method actually uses Java's default time-zone on the fly to provide the string. The time-zone is not part of the actual state of java.util.Date.

An Instant also does not contain any information about the time-zone. Thus, to convert from an Instant to a local date it is necessary to specify a time-zone. This might be the default zone - ZoneId.systemDefault() - or it might be a time-zone that your application controls, such as a time-zone from user preferences. Use the atZone() method to apply the time-zone:

Date input = new Date();
Instant instant = input.toInstant();
ZonedDateTime zdt = instant.atZone(ZoneId.systemDefault());

A ZonedDateTime contains state consisting of the local date and time, time-zone and the offset from GMT/UTC. As such the date - LocalDate - can be easily extracted using toLocalDate():

Date input = new Date();
Instant instant = input.toInstant();
ZonedDateTime zdt = instant.atZone(ZoneId.systemDefault());
LocalDate date = zdt.toLocalDate();
Improve this answer
Sign up to request clarification or add additional context in comments.

18 Comments

I had LocalDate.from(Instant.ofEpochMilli(date.getTime())) I think it's equivalent to yours, but more direct.
@MarkoTopolnik that compiles but does not run. An Instant does not contain a time-zone thus there is no way to get the LocalDate.
@assylias Just use sqlDate.toLocalDate() !
@JodaStephen Date has no concept of time-zone, Instant also does not contain information about time-zone. The LocalDate API says "A date without a time-zone". Then why converting from Date to Instant to LocalDate needs atZone(ZoneId.systemDefault())?
@Gustavo: LocalDate and LocalDateTime do not "store or represent a time or time-zone" (ref: javadocs). While they don't store it- the classes do represent a Local date and/or time, hence the conversion to local date/time implies a timezone.
|
193

Better way is:

Date date = ...;
Instant.ofEpochMilli(date.getTime()).atZone(ZoneId.systemDefault()).toLocalDate()

Advantages of this version:

  • works regardless the input is an instance of java.util.Date or it's a subclass of java.sql.Date (unlike @JodaStephen's way). This is common with JDBC-originated data. java.sql.Date.toInstant() always throws an exception.

  • it's the same for JDK8 and JDK7 with JSR-310 backport

I personally use an utility class (but it is not backport-compatible):

/**
 * Utilities for conversion between the old and new JDK date types 
 * (between {@code java.util.Date} and {@code java.time.*}).
 * 
 * <p>
 * All methods are null-safe.
 */
public class DateConvertUtils {

    /**
     * Calls {@link #asLocalDate(Date, ZoneId)} with the system default time zone.
     */
    public static LocalDate asLocalDate(java.util.Date date) {
        return asLocalDate(date, ZoneId.systemDefault());
    }

    /**
     * Creates {@link LocalDate} from {@code java.util.Date} or it's subclasses. Null-safe.
     */
    public static LocalDate asLocalDate(java.util.Date date, ZoneId zone) {
        if (date == null)
            return null;

        if (date instanceof java.sql.Date)
            return ((java.sql.Date) date).toLocalDate();
        else
            return Instant.ofEpochMilli(date.getTime()).atZone(zone).toLocalDate();
    }

    /**
     * Calls {@link #asLocalDateTime(Date, ZoneId)} with the system default time zone.
     */
    public static LocalDateTime asLocalDateTime(java.util.Date date) {
        return asLocalDateTime(date, ZoneId.systemDefault());
    }

    /**
     * Creates {@link LocalDateTime} from {@code java.util.Date} or it's subclasses. Null-safe.
     */
    public static LocalDateTime asLocalDateTime(java.util.Date date, ZoneId zone) {
        if (date == null)
            return null;

        if (date instanceof java.sql.Timestamp)
            return ((java.sql.Timestamp) date).toLocalDateTime();
        else
            return Instant.ofEpochMilli(date.getTime()).atZone(zone).toLocalDateTime();
    }

    /**
     * Calls {@link #asUtilDate(Object, ZoneId)} with the system default time zone.
     */
    public static java.util.Date asUtilDate(Object date) {
        return asUtilDate(date, ZoneId.systemDefault());
    }

    /**
     * Creates a {@link java.util.Date} from various date objects. Is null-safe. Currently supports:<ul>
     * <li>{@link java.util.Date}
     * <li>{@link java.sql.Date}
     * <li>{@link java.sql.Timestamp}
     * <li>{@link java.time.LocalDate}
     * <li>{@link java.time.LocalDateTime}
     * <li>{@link java.time.ZonedDateTime}
     * <li>{@link java.time.Instant}
     * </ul>
     * 
     * @param zone Time zone, used only if the input object is LocalDate or LocalDateTime.
     * 
     * @return {@link java.util.Date} (exactly this class, not a subclass, such as java.sql.Date)
     */
    public static java.util.Date asUtilDate(Object date, ZoneId zone) {
        if (date == null)
            return null;

        if (date instanceof java.sql.Date || date instanceof java.sql.Timestamp)
            return new java.util.Date(((java.util.Date) date).getTime());
        if (date instanceof java.util.Date)
            return (java.util.Date) date;
        if (date instanceof LocalDate)
            return java.util.Date.from(((LocalDate) date).atStartOfDay(zone).toInstant());
        if (date instanceof LocalDateTime)
            return java.util.Date.from(((LocalDateTime) date).atZone(zone).toInstant());
        if (date instanceof ZonedDateTime)
            return java.util.Date.from(((ZonedDateTime) date).toInstant());
        if (date instanceof Instant)
            return java.util.Date.from((Instant) date);

        throw new UnsupportedOperationException("Don't know hot to convert " + date.getClass().getName() + " to java.util.Date");
    }

    /**
     * Creates an {@link Instant} from {@code java.util.Date} or it's subclasses. Null-safe.
     */
    public static Instant asInstant(Date date) {
        if (date == null)
            return null;
        else
            return Instant.ofEpochMilli(date.getTime());
    }

    /**
     * Calls {@link #asZonedDateTime(Date, ZoneId)} with the system default time zone.
     */
    public static ZonedDateTime asZonedDateTime(Date date) {
        return asZonedDateTime(date, ZoneId.systemDefault());
    }

    /**
     * Creates {@link ZonedDateTime} from {@code java.util.Date} or it's subclasses. Null-safe.
     */
    public static ZonedDateTime asZonedDateTime(Date date, ZoneId zone) {
        if (date == null)
            return null;
        else
            return asInstant(date).atZone(zone);
    }

}

The asLocalDate() method here is null-safe, uses toLocalDate(), if input is java.sql.Date (it may be overriden by the JDBC driver to avoid timezone problems or unnecessary calculations), otherwise uses the abovementioned method.

Improve this answer

8 Comments

It is better in comparison to the accepted answer, I explain why. Yes, it is ugly, but that's why wrote DateConvertUtils.
I don't understand why they didn't implement a conversion class in the new API.
@ceklock, they did implement, not a conversion class, but a couple of conversion methods, like Date.toInstant().
Is there a Kotlin library that packages these as extension functions so that a developer can do the following. Date x = ...; x.asLocalDate();
@MarkAshworth I don't know of any
|
28 
LocalDate localDate = LocalDate.parse( new SimpleDateFormat("yyyy-MM-dd").format(date) );
Improve this answer

4 Comments

Here, the SimpleDateFormat instance is confined to the current thread. It is used in a thread-safe way. Now, SimpleDateFormat is reputed to be 'expensive to instantiate' (on account of all the internal data structures it needs) but you can't share one as a 'singleton' (without synchronizing access to it), because it is indeed not thread-safe. (A ThreadLocal solution can work if the code 'polluting' the Thread in this was is responsible for the thread's lifecycle ... but that rarely happens). Awkward. Avoiding SimpleDateFormat is the reason for using javax.time.
This approach has a lot of overhead: the 'expensive' SimpleDateFormat (which is thrown away), the intermediate string (which is thrown away), and the cost of parsing. It's a solution, but not recommended.
@ceklock but then you get the problem that it's no longer thread-safe
@ceklock the SimpleDateFormat can only process one date at a time, if you use it concurrently, it'll yield mangled results. So yes, it is important. Don't create a single instance of SimpleDateFormat in a global variable.
22

If you're using Java 8, @JodaStephen's answer is obviously the best. However, if you're working with the JSR-310 backport, you unfortunately have to do something like this:

Date input = new Date();
Calendar cal = Calendar.getInstance();
cal.setTime(input);
LocalDate date = LocalDate.of(cal.get(Calendar.YEAR),
        cal.get(Calendar.MONTH) + 1,
        cal.get(Calendar.DAY_OF_MONTH));
Improve this answer

3 Comments

Not true, @JodaStephen's answer still works. You just need another way to convert java.util.Date to an Instant. For this you can use org.threeten.bp.DateTimeUtils.toInstant: threeten.org/threetenbp/apidocs/org/threeten/bp/…
DateTimeUtils wasn't available when I was using the backport, but you are correct that it is available to anyone using ThreeTen Backport 1.0 or later. Thanks for pointing it out.
@ChristianCiach You are correct. I spelled out what you are saying in this answer.
16 
LocalDate ld = new java.sql.Date( new java.util.Date().getTime() ).toLocalDate();
Improve this answer

2 Comments

And it simplest realization: LocalDate.of(getYear() + 1900, getMonth() + 1, getDate())
The lines that say deprecated though :|
11

You can convert in one line :

public static LocalDate getLocalDateFromDate(Date date){
   return LocalDate.from(Instant.ofEpochMilli(date.getTime()).atZone(ZoneId.systemDefault()));
}
Improve this answer

2 Comments

I get an error like this using this method: java.time.DateTimeException: Unable to obtain LocalDate from TemporalAccessor: 2018-01-31T11:54:27.964Z of type java.time.Instant
@LuigiRubino thanks for pointing out. Please see the updated answer. I forgot to add Zone earlier.
9

first, it's easy to convert a Date to an Instant

Instant timestamp = new Date().toInstant();

Then, you can convert the Instant to any date api in jdk 8 using ofInstant() method:

LocalDateTime date = LocalDateTime.ofInstant(timestamp, ZoneId.systemDefault());
Improve this answer

4 Comments

includes localDate, localDateTime, localTime
What does it mean to specify ZoneId here. If I get Date -> Instant from API and I can think about it as milliseconds from 1970 in UTC. When I want to get just corresponding LocalDate (yyyy-mm-dd) from perspective of api not converted to any timezone, shouldn't I use ZoneOffset.UTC to not have this instant offset to my local timezone. Isn't your example with ZoneId.systemDefault() is shifting date form server. Ex. instant represents 2018-10-20 0:00 and then shifted from UTC to America/Los_Angeles I get in Local Date 2018-10-19 instead of 2018-10-20?
It breaks if you happen to have import java.sql.Date in your file: the toInstant() method of java.sql.Date always throws.
Thanks Michał. I was struggling with the same concept since all the examples use systemDefault. I tested this out and you are correct, I should use ZoneOffset.UTC since I don't want the date value offset/modified. This answer helped clarify it for me: stackoverflow.com/a/40143687/2371207
8

To simplify the process of converting LocalDate/time to Date and vice versa, I created two charts:

  1. converting LocalDate to Date and vice versa:

enter image description here

  1. converting LocalDateTime to Date and vice versa:

enter image description here

Improve this answer

2 Comments

wrong, java.util.date does not have any timezone; it's just the current timezone which is used when formatting or calling toString()...
Incorrect: java.sql.Timestamp is replaced by java.time.OffsetDateTime in JDBC, definitely not LocalDateTime which discards the valuable info of offset/zone. Likewise, going from ZonedDateTime to LocalDateTime makes no sense as you are discarding valuable time zone info with nothing gained in return.
7 
Date input = new Date();
LocalDateTime  conv=LocalDateTime.ofInstant(input.toInstant(), ZoneId.systemDefault());
LocalDate convDate=conv.toLocalDate();

The Date instance does contain time too along with the date while LocalDate doesn't. So you can firstly convert it into LocalDateTime using its method ofInstant() then if you want it without time then convert the instance into LocalDate.

Improve this answer

Comments

2

If you are using ThreeTen Backport including ThreeTenABP

    Date input = new Date(); // Imagine your Date here
    LocalDate date = DateTimeUtils.toInstant(input)
            .atZone(ZoneId.systemDefault())
            .toLocalDate();

If you are using the backport of JSR 310, either you haven’t got a Date.toInstant() method or it won’t give you the org.threeten.bp.Instant that you need for you further conversion. Instead you need to use the DateTimeUtils class that comes as part of the backport. The remainder of the conversion is the same, so so is the explanation.

Improve this answer

Comments

1 
public static LocalDate Date2LocalDate(Date date) {
        return LocalDate.parse(date.toString(), DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss zzz yyyy"))

this format is from Date#tostring

    public String toString() {
        // "EEE MMM dd HH:mm:ss zzz yyyy";
        BaseCalendar.Date date = normalize();
        StringBuilder sb = new StringBuilder(28);
        int index = date.getDayOfWeek();
        if (index == BaseCalendar.SUNDAY) {
            index = 8;
        }
        convertToAbbr(sb, wtb[index]).append(' ');                        // EEE
        convertToAbbr(sb, wtb[date.getMonth() - 1 + 2 + 7]).append(' ');  // MMM
        CalendarUtils.sprintf0d(sb, date.getDayOfMonth(), 2).append(' '); // dd

        CalendarUtils.sprintf0d(sb, date.getHours(), 2).append(':');   // HH
        CalendarUtils.sprintf0d(sb, date.getMinutes(), 2).append(':'); // mm
        CalendarUtils.sprintf0d(sb, date.getSeconds(), 2).append(' '); // ss
        TimeZone zi = date.getZone();
        if (zi != null) {
            sb.append(zi.getDisplayName(date.isDaylightTime(), TimeZone.SHORT, Locale.US)); // zzz
        } else {
            sb.append("GMT");
        }
        sb.append(' ').append(date.getYear());  // yyyy
        return sb.toString();
    }
Improve this answer

Comments

0

I have had problems with @JodaStephen's implementation on JBoss EAP 6. So, I rewrote the conversion following Oracle's Java Tutorial in http://docs.oracle.com/javase/tutorial/datetime/iso/legacy.html.

    Date input = new Date();
    GregorianCalendar gregorianCalendar = (GregorianCalendar) Calendar.getInstance();
    gregorianCalendar.setTime(input);
    ZonedDateTime zonedDateTime = gregorianCalendar.toZonedDateTime();
    zonedDateTime.toLocalDate();
Improve this answer

Comments

-2

What's wrong with this 1 simple line?

new LocalDateTime(new Date().getTime()).toLocalDate();
Improve this answer

1 Comment

Java complains that it cannot invoke toLocalDate() on the primitive type long. I used an actual Date object; perhaps there's the rub??
-9

I solved this question with solution below

  import org.joda.time.LocalDate;
  Date myDate = new Date();
  LocalDate localDate = LocalDate.fromDateFields(myDate);
  System.out.println("My date using Date" Nov 18 11:23:33 BRST 2016);
  System.out.println("My date using joda.time LocalTime" 2016-11-18);

In this case localDate print your date in this format "yyyy-MM-dd"

Improve this answer

1 Comment

The question is looking for a solution using the java.time classes in JDK8, not with Joda Time.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.