Java 8 – How to convert Instant to LocalDateTime ?

August 20, 2022 SJ Java 8, Java 8 Date/Time 0

In this article, we will learn different ways to convert an Instant to LocalDateTime using different methods provided in Java 1.8 version

For LocalDateTime to an Instant conversion, read Java 8 – How to convert LocalDateTime to an Instant ?

1. Convert Instant to LocalDateTime :

Direct conversion from Instant to LocalDateTime is possible using LocalDateTime.ofInstant() method of LocalDateTime class or else both ZonedDateTime/OffsetDateTime classes has toLocalDateTime() method

  1. Convert Instant to LocalDateTime
  2. Convert Instant to LocalDateTime via ZonedDateTime
  3. Convert Instant to LocalDateTime via OffsetDateTime

1.1 Convert Instant to LocalDateTime :

  • Convert Instant to LocalDateTime using LocalDateTime.ofInstant() method passing instant & ZoneOffset as input–argument

ConvertInstantToLocalDateTime1.java

package in.bench.resources.java8.instant.examples;

import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneOffset;

public class ConvertInstantToLocalDateTime1 {

	public static void main(String[] args) {

		// 1. get instantaneous moment at UTC/GMT
		Instant instant = Instant.now();
		System.out.println("Current Instant at UTC/GMT is :- \n" + instant);


		// 2. convert Instant to LocalDateTime
		LocalDateTime localDateTime = LocalDateTime
				.ofInstant(instant, ZoneOffset.UTC);
		System.out.print("\nLocalDateTime is :- \n" + localDateTime);
	}
}

Output:

Current Instant at UTC/GMT is :- 
2022-08-19T16:25:10.351805600Z

LocalDateTime is :- 
2022-08-19T16:25:10.351805600

1.2 Convert Instant to LocalDateTime via ZonedDateTime :

  • First step is to convert Instant to ZonedDateTime using ZonedDateTime.ofInstant() method passing instant & ZoneOffset as input–arguments
  • After converting to ZonedDateTime, use/invoke toLocalDateTime() method of ZonedDateTime to convert into LocalDateTime as shown in the below illustration

ConvertInstantToLocalDateTime2.java

package in.bench.resources.java8.instant.examples;

import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;

public class ConvertInstantToLocalDateTime2 {

	public static void main(String[] args) {

		// get instantaneous moment at UTC/GMT
		Instant instant = Instant.now();
		System.out.println("Current Instant at UTC/GMT is :- \n" + instant);


		// 1. convert Instant to ZonedDateTime
		ZonedDateTime zonedDateTime = ZonedDateTime
				.ofInstant(instant, ZoneOffset.UTC);
		System.out.println("\nZonedDateTime is :- \n" + zonedDateTime);


		// 2. Instant -> ZonedDateTime -> LocalDateTime
		LocalDateTime localDateTime = zonedDateTime.toLocalDateTime();
		System.out.print("\nLocalDateTime is :- \n" + localDateTime);
	}
}

Output:

Current Instant at UTC/GMT is :- 
2022-08-19T16:25:45.825023200Z

ZonedDateTime is :- 
2022-08-19T16:25:45.825023200Z

LocalDateTime is :- 
2022-08-19T16:25:45.825023200

1.3 Convert Instant to LocalDateTime via OffsetDateTime :

  • First step is to convert Instant to an OffsetDateTime using OffsetDateTime.ofInstant() method passing instant & ZoneOffset as input–arguments
  • After converting to an OffsetDateTime, use/invoke toLocalDateTime() method of OffsetDateTime to convert into LocalDateTime as shown in the below illustration

ConvertInstantToLocalDateTime3.java

package in.bench.resources.java8.instant.examples;

import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.OffsetDateTime;

public class ConvertInstantToLocalDateTime3 {

	public static void main(String[] args) {

		// get instantaneous moment at UTC/GMT
		Instant instant = Instant.now();
		System.out.println("Current Instant at UTC/GMT is :- \n" + instant);


		// 1. convert Instant to OffsetDateTime
		OffsetDateTime offsetDateTime = OffsetDateTime
				.ofInstant(instant, ZoneOffset.UTC);
		System.out.println("\nOffsetDateTime is :- \n" + offsetDateTime);


		// 2. Instant -> OffsetDateTime -> LocalDateTime
		LocalDateTime localDateTime = offsetDateTime.toLocalDateTime();
		System.out.print("\nLocalDateTime is :- \n" + localDateTime);
	}
}

Output:

Current Instant at UTC/GMT is :- 
2022-08-19T16:26:17.329992100Z

OffsetDateTime is :- 
2022-08-19T16:26:17.329992100Z

LocalDateTime is :- 
2022-08-19T16:26:17.329992100

2. Convert LocalDateTime to an Instant :

ConvertLocalDateTimeToInstant.java

package in.bench.resources.java8.localdatetime.examples;

import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneOffset;

public class ConvertLocalDateTimeToInstant {

	public static void main(String[] args) {

		// 1. get current System Date/time
		LocalDateTime localDateTime = LocalDateTime.now();
		System.out.println("Current System Date/time is :- \n" + localDateTime);


		// 2. get system default zone offset
		ZoneOffset zoneOffset = ZoneOffset.of("+05:30");
		System.out.println("\nZone Offset is :- \n" + zoneOffset);


		// 3. convert LocalDateTime to an Instant using toInstant(zoneOffset)
		Instant instant = localDateTime.toInstant(zoneOffset);
		System.out.print("\nConversion of LocalDateTime to Instant is :- \n"
				+ instant);
	}
}

Output:

Current System Date/time is :- 
2022-08-19T21:52:09.614339800

Zone Offset is :- 
+05:30

Conversion of LocalDateTime to Instant is :- 
2022-08-19T16:22:09.614339800Z

Related Articles:

References:

Happy Coding !!
Happy Learning !!

Java 8 – How to convert Instant to ZonedDateTime ?
Java 8 – How to convert Instant to LocalTime ?

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