Develop Reference

How to convert date string in EDT to UTC date?

I am reading data from upstream system and it returns the date in string format like this,
String dateFromUpstream = 11-14-2022 10:41:12 EDT
Now, I want to convert this string to a date format of UTC timezone and then store it into my entity.
I tried the following way,
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MM-dd-yyyy HH:mm:ss z");
LocalDateTime date = ZonedDateTime.parse(dateFromUpstream, formatter).toLocalDateTime().atZone(ZoneId.of("UTC"));
But this doesn't change the date to UTC timezone. It still gives me the same date with UTC instead of EDT at the end of the string.
Anyone know how I can do this and then store into an entity?

Parse the given date-time string into a ZonedDateTime with the corresponding DateTimeFormatter and then convert the resulting ZonedDateTime into an Instant or another ZonedDateTime corresponding to UTC, using ZonedDateTime#withZoneSameInstant.
Demo:
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Locale;
public class Main {
public static void main(String[] args) {
String dateFromUpstream = "11-14-2022 10:41:12 EDT";
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("MM-dd-uuuu HH:mm:ss z", Locale.ENGLISH);
ZonedDateTime zdt = ZonedDateTime.parse(dateFromUpstream, dtf);
Instant instant = zdt.toInstant();
System.out.println(instant);
// Or get a ZonedDateTime at UTC
ZonedDateTime zdtUTC = zdt.withZoneSameInstant(ZoneOffset.UTC);
System.out.println(zdtUTC);
// If you want LocalDateTime
LocalDateTime ldt = zdtUTC.toLocalDateTime();
System.out.println(ldt);
}
}
See this code run at Ideone.com.
Output:
2022-11-14T15:41:12Z
2022-11-14T15:41:12Z
2022-11-14T15:41:12
Learn more about the modern Date-Time API from Trail: Date Time.
Note: As suggested by Basil Bourque, you can convert the parsed date-time into an OffsetDateTime at UTC as shown below:
OffsetDateTime odtUTC = zdt.toOffsetDateTime()
.withOffsetSameInstant(ZoneOffset.UTC);

Convert UTC datetime to local datetime using java.time

I have a UTC date-time like this (a String): 2022-11-22T17:15:00
And a ZoneID like this: "America/Tijuana"
Using java.time API, I want to get the actual datetime for that zone, which is: 2022-11-22T09:15:00 (the time is 09:15 instead of 17:15)
ZonedDateTime.toLocalDateTime() returns: 2022-11-22T17:15
ZonedDateTime.toString() returns:
2022-11-22T17:15-08:00[America/Tijuana]
None of the above gives me what I'm looking for.
This is my code:
ZoneId zonaID = ZoneId.of('America/Tijuana');
CharSequence dateUTC = "2022-11-22T17:15:00";
LocalDateTime dateTimeL = LocalDateTime.parse(dateUTC);
ZonedDateTime myZDT = ZonedDateTime.now();
ZonedDateTime myZDTFinal = myZDT.of(dateTimeL, zonaID);
System.out.println("using toLocalDateTime: " + myZDTFinal.toLocalDateTime());
System.out.println("using toString: " + myZDTFinal.toString());
I know that this might be a duplicated question but there's so many questions about date-times and I just haven't been able to figure out this.
Any help will be really appreciated.

You have to convert your date to UTC, then convert the convert this zone to your expected zone using withZoneSameInstant like this:
ZonedDateTime toUTCZone = ZonedDateTime.of(dateTimeL, ZoneOffset.UTC);
ZonedDateTime myZDTFinal = toUTCZone.withZoneSameInstant(zonaID);
Output
2022-11-22T09:15-08:00[America/Tijuana]

There can be many ways to achieve the result. A simple approach would be
Parse the given string into LocalDateTime.
Convert it into an OffsetDateTime at UTC using LocalDateTime#atOffset.
Use OffsetDateTime#atZoneSameInstant to convert the resulting OffsetDateTime into a ZonedDateTime at ZoneId.of("America/Tijuana").
Get LocalDateTime out of the resulting ZonedDateTime by using ZonedDateTime#toLocalDateTime.
If required, format this LocalDateTime into the desired string.
LocalDateTime
.parse("2022-11-22T17:15:00") // Parse the given date-time string into LocalDateTime
.atOffset(ZoneOffset.UTC) // Convert it into a ZonedDateTime at UTC
.atZoneSameInstant(ZoneId.of("America/Tijuana")) // Convert the result into a ZonedDateTime at another time-zome
.toLocalDateTime() // Get the LocalDateTime out of the ZonedDateTime
.format(DateTimeFormatter.ofPattern("uuuu-MM-dd'T'HH:mm:ss", Locale.ENGLISH))); // If required
Demo:
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;
import java.util.Locale;
public class Main {
public static void main(String[] args) {
LocalDateTime ldtInTijuana = LocalDateTime.parse("2022-11-22T17:15:00")
.atOffset(ZoneOffset.UTC)
.atZoneSameInstant(ZoneId.of("America/Tijuana"))
.toLocalDateTime();
System.out.println(ldtInTijuana);
// Custom format
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("uuuu-MM-dd'T'HH:mm:ss", Locale.ENGLISH);
String formatted = ldtInTijuana.format(formatter);
System.out.println(formatted);
}
}
Output:
2022-11-22T09:15
2022-11-22T09:15:00
Note that LocalDateTime#toString removes second and fraction-of-second values if they are zero. Suppose you want to keep them (as you have posted in your question), you can use a DateTimeFormatter as shown above.
An alternate approach:
Alternatively, you can append Z at the end of your ISO 8601 formatted date-time string to enable Instant to parse it and then convert the Instant into a ZonedDateTime corresponding to the ZoneId.of("America/Tijuana") by using Instant#atZone. The symbol, Z refers to UTC in a date-time string.
The rest of the steps will remain the same.
Demo:
public class Main {
public static void main(String[] args) {
String text = "2022-11-22T17:15:00";
text = text + "Z"; // Z refers to UTC
Instant instant = Instant.parse(text);
LocalDateTime ldt = instant.atZone(ZoneId.of("America/Tijuana")).toLocalDateTime();
System.out.println(ldt);
}
}
Output:
2022-11-22T09:15
Learn more about the modern Date-Time API from Trail: Date Time.

Get a LocalDateTime object from a given string?

"2021-09-17 11:48:06 UTC"
I want to parse the following string and create a LocalDateTime object or an Instant
I know you can write something like this
String dateTime = "2021-09-17 11:48:06 UTC";
LocalDateTime dt = LocalDateTime.parse(dateTime,DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
How do I deal with the UTC part in the string?

Never hardcode the standard timezone text like UTC, GMT etc.
Never hardcode the standard timezone text like UTC, GMT etc. which DateTimeFormatter is already capable of handling in the best way.
Parse the given Date-Time string using the pattern, uuuu-MM-dd HH:mm:ss VV into a TemporalAccessor from which you can get the Instant as well as the LocalDateTime.
Demo:
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.time.temporal.TemporalAccessor;
import java.util.Locale;
public class Main {
public static void main(String[] args) {
String strDateTime = "2021-09-17 11:48:06 UTC";
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss VV", Locale.ENGLISH);
TemporalAccessor temporalAccessor = dtf.parse(strDateTime);
Instant instant = Instant.from(temporalAccessor);
LocalDateTime ldt = LocalDateTime.from(temporalAccessor);
System.out.println(instant);
System.out.println(ldt);
}
}
Output:
2021-09-17T11:48:06Z
2021-09-17T11:48:06
ONLINE DEMO
Alternatively:
Parse the given Date-Time string using the pattern, uuuu-MM-dd HH:mm:ss VV into a ZonedDateTime from which you can get the Instant as well as the LocalDateTime.
Demo:
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Locale;
public class Main {
public static void main(String[] args) {
String strDateTime = "2021-09-17 11:48:06 UTC";
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss VV", Locale.ENGLISH);
ZonedDateTime zdt = ZonedDateTime.parse(strDateTime, dtf);
Instant instant = Instant.from(zdt);
LocalDateTime ldt = zdt.toLocalDateTime();
System.out.println(zdt);
System.out.println(instant);
System.out.println(ldt);
}
}
Output:
2021-09-17T11:48:06Z[UTC]
2021-09-17T11:48:06Z
2021-09-17T11:48:06
ONLINE DEMO
Learn more about the modern Date-Time API* from Trail: Date Time.
* For any reason, if you have to stick to Java 6 or Java 7, you can use ThreeTen-Backport which backports most of the java.time functionality to Java 6 & 7. If you are working for an Android project and your Android API level is still not compliant with Java-8, check Java 8+ APIs available through desugaring and How to use ThreeTenABP in Android Project.

"2021-09-17 11:48:06 UTC" isn't a local date time: it's a date time, because it has a time zone. And because your time has a time zone, it doesn't match your pattern, which doesn't.
If your time strings always end with exactly "UTC", you can make that a literal in the pattern:
DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss 'UTC'");
If you need to handle other time zones than UTC, you can use z:
DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss z");
but note that this is for parsing a zoned date time; from that, you can extract the local date time:
ZonedDateTime zdt = ZonedDateTime.parse(dateTime,DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss z");
LocalDateTime ldt =z dt.toLocalDateTime();

Parsing LocalDate to ZonedDateTime in correct format

Given:
public static void main(String[] args) {
String dateString = "2018-07-30T13:36:17.820";
DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter
.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSS");
LocalDate date = LocalDate.parse(dateString, DATE_TIME_FORMATTER);
ZonedDateTime zonedDateTime = date.atStartOfDay((ZoneOffset.UTC));
System.out.println(zonedDateTime);
}
And output:
2018-07-30T00:00Z
...what is the pattern to print seconds? Stupid question no doubt but driving me a little nuts
I need:
2018-07-30T00:00:00Z

I changed java.time.LocalDate to java.time.LocalDateTime, you need it if you want to show also the seconds.
package com.test;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
public class DateFormatter {
public static void main(String[] args) {
String dateString = "2018-07-30T13:36:17.820";
DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter
.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSS");
LocalDateTime date = LocalDateTime.parse(dateString, DATE_TIME_FORMATTER);
ZonedDateTime zonedDateTime = date.atZone(ZoneOffset.UTC);
System.out.println(zonedDateTime);
}
}
Output is:
2018-07-30T13:36:17.820Z

LocalDate will keep just date. You need to parse LocalDateTime and convert to ZonedDateTime and you will have seconds as you expect.
var dateString = "2018-07-30T13:36:17.820";
var format = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSS");
var localDate = LocalDateTime.parse(dateString, format);
var zone = ZoneId.of( "America/Montreal" );
var zonedDateTime = localDate.atZone(zone);
System.out.println(zonedDateTime);

You will have to go a few steps:
parse the String to a LocalDateTime because it contains date and time of day
extract the date only
create a ZonedDateTime out of that by adding the start of day (LocalTime.MIN = 00:00:00) and a ZoneOffset.UTC
This code may do:
public static void main(String[] args) {
String dateString = "2018-07-30T13:36:17.820";
// parse a LocalDateTime
LocalDateTime localDateTime = LocalDateTime.parse(dateString);
// extract the date part
LocalDate localDate = localDateTime.toLocalDate();
// make it a ZonedDateTime by applying a ZoneId
ZonedDateTime zonedDateTime = ZonedDateTime.of(localDate, LocalTime.MIN, ZoneOffset.UTC);
// print the result
System.out.println(zonedDateTime.format(DateTimeFormatter.ISO_ZONED_DATE_TIME));
}
Output is
2018-07-30T00:00:00Z
There are several ways to do it, this is just one of them and it just slightly differs from most of the other answers (and comments :-) ).

tl;dr
You have used the wrong things in the wrong places.
You do not need a DateTimeFormatter explicitly in order to parse 2018-07-30T13:36:17.820 because it's already in ISO 8601 format which is also the default format used by LocalDateTime#parse. Moreover, this string has date and time instead of just date; therefore, it makes more sense to parse it into LocalDateTime instead of LocalDate. You can always get LocalDate from LocalDateTime using LocalDateTime#toLocalDate.
The ZonedDateTime#toString uses the LocalDateTime#toString which in turn uses LocalTime#toString for the time part which omits second and fraction-of-second if they are zero. If you need a string with zero second and fraction-of-second, you will need to use a DateTimeFormatter.
Demo:
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
public class Main {
public static void main(String args[]) {
String dateString = "2018-07-30T13:36:17.820";
LocalDateTime localDateTime = LocalDateTime.parse(dateString);// You do not need a DateTimeFormatter here
ZonedDateTime zonedDateTime = localDateTime.toLocalDate().atStartOfDay(ZoneOffset.UTC);
// Print zonedDateTime.toString()
System.out.println(zonedDateTime);
// Custom format
final DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSS");
System.out.println(DATE_TIME_FORMATTER.format(zonedDateTime));
}
}
Output:
2018-07-30T00:00Z
2018-07-30T00:00:00.000
Learn more about the modern date-time API from Trail: Date Time.

Local DateTime cannot be parsed in Java 11

I have below code.
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSSZ");
LocalDateTime myDate = LocalDateTime.parse("2020-11-16T02:27:39.345Z", formatter);
But it throws below error in the second line. Not sure why it's complaining Z
java.time.format.DateTimeParseException: Text '2020-11-16T02:27:39.345Z' could not be parsed at index 23
at java.base/java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:2046)
at java.base/java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1948)
at java.base/java.time.LocalDateTime.parse(LocalDateTime.java:492)

LocalDateTime does not have timezone or zone-offset information whereas your date-time string has zone-offset. The letter, Z at the end of your date-time string stands for Zulu i.e. zone-offset of UTC. You can parse it into OffsetDateTime or ZonedDateTime or Instant directly (i.e. without using a custom DateTimeFormatter).
Demo:
import java.time.Instant;
import java.time.OffsetDateTime;
import java.time.ZonedDateTime;
public class Main {
public static void main(String[] args) {
String dateTimeString = "2020-11-16T02:27:39.345Z";
OffsetDateTime odt = OffsetDateTime.parse(dateTimeString);
System.out.println(odt);
ZonedDateTime zdt = ZonedDateTime.parse(dateTimeString);
System.out.println(zdt);
Instant instant = Instant.parse(dateTimeString);
System.out.println(instant);
}
}
Output:
2020-11-16T02:27:39.345Z
2020-11-16T02:27:39.345Z
2020-11-16T02:27:39.345Z