Java LocalDate to Instant and Timestamp
May 11, 2019
java.time.LocalDate into java.time.Instant and java.sql.Timestamp. The LocalDate represents a date in the format yyyy-MM-dd such as 2019-05-16. The Instant is an instantaneous point on the time-line. The Timestamp is a thin wrapper around java.util.Date that allows the JDBC API to identify this as an SQL TIMESTAMP value.
1. Find the sample code to convert
LocalDate to Instant.
LocalDate localDate = LocalDate.parse("2019-05-16");
Instant instant = localDate.atStartOfDay(ZoneId.systemDefault()).toInstant();
System.out.println(instant);//2019-05-15T18:30:00Z
LocalDate to Timestamp.
LocalDate localDate = LocalDate.parse("2019-05-16");
Timestamp timestamp = Timestamp.valueOf(localDate.atTime(LocalTime.MIDNIGHT));
System.out.println(timestamp); //2019-05-16 00:00:00.0
LocalDate into Instant and Timestamp.
Contents
1. LocalDate to Instant
To convertLocalDate to Instant, we will convert LocalDate into ZonedDateTime or Timestamp and then calling their toInstant() method we get Instant.
1.1 Using LocalDate.atTime
LocalDate.atTime method combines this date with a given time to create a LocalDateTime. The LocalDateTime.atZone combines this date-time with a time-zone to create a ZonedDateTime. The ZonedDateTime.toInstant converts this date-time to an Instant.
Example:
LocalDate localDate = LocalDate.parse("2019-05-16");
Instant instant = localDate.atTime(LocalTime.MIDNIGHT).atZone(ZoneId.systemDefault()).toInstant();
System.out.println(instant); //2019-05-15T18:30:00Z
1.2. Using LocalDate.atStartOfDay
Example-1:LocalDate.atStartOfDay(zone) returns a zoned date-time from this date at the earliest valid time according to the rules in the time-zone.
LocalDate localDate = LocalDate.parse("2019-05-16");
Instant instant = localDate.atStartOfDay(ZoneId.systemDefault()).toInstant();
System.out.println(instant);//2019-05-15T18:30:00Z
LocalDate.atStartOfDay() combines this date with the time of midnight to create a LocalDateTime at the start of this date.
LocalDate localDate = LocalDate.parse("2019-05-16");
Instant instant = localDate.atStartOfDay().atZone(ZoneId.systemDefault()).toInstant();
System.out.println(instant); //2019-05-15T18:30:00Z
1.3. Using LocalDateTime.of
LocalDateTime.of obtains an instance of LocalDateTime from a date and time.
Example:
LocalDate localDate = LocalDate.parse("2019-05-16");
Instant instant = LocalDateTime.of(localDate, LocalTime.MIDNIGHT).atZone(ZoneId.systemDefault()).toInstant();
System.out.println(instant); //2019-05-15T18:30:00Z
2. LocalDate to Timestamp
Timestamp.valueOf(dateTime) obtains an instance of Timestamp from a LocalDateTime object.
Example-1: Instantiate
LocalDateTime using LocalDate.atTime method.
LocalDate localDate = LocalDate.parse("2019-05-16");
Timestamp timestamp = Timestamp.valueOf(localDate.atTime(LocalTime.MIDNIGHT));
System.out.println(timestamp); //2019-05-16 00:00:00.0
LocalDateTime using LocalDateTime.of method.
LocalDate localDate = LocalDate.parse("2019-05-16");
Timestamp timestamp = Timestamp.valueOf(LocalDateTime.of(localDate, LocalTime.MIDNIGHT));
System.out.println(timestamp); //2019-05-16 00:00:00.0
3. Timestamp to Instant
We can convertTimestamp to Instant using Timestamp.toInstant() method.
Example:
LocalDate localDate = LocalDate.parse("2019-05-16");
Timestamp timestamp = Timestamp.valueOf(LocalDateTime.of(localDate, LocalTime.MIDNIGHT));
Instant instant = timestamp.toInstant();
System.out.println(instant); //2019-05-15T18:30:00Z
Complete Example
LocalDateDemo.java
package com.concretepage;
import java.sql.Timestamp;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.ZoneId;
public class LocalDateDemo {
public static void main(String[] args) {
LocalDate localDate = LocalDate.parse("2019-05-16");
System.out.println("---Instant---");
Instant instant = localDate.atTime(LocalTime.MIDNIGHT).atZone(ZoneId.systemDefault()).toInstant();
System.out.println(instant);
instant = localDate.atStartOfDay(ZoneId.systemDefault()).toInstant();
System.out.println(instant);
instant = localDate.atStartOfDay().atZone(ZoneId.systemDefault()).toInstant();
System.out.println(instant);
instant = LocalDateTime.of(localDate, LocalTime.MIDNIGHT).atZone(ZoneId.systemDefault()).toInstant();
System.out.println(instant);
System.out.println("---Timestamp---");
Timestamp timestamp = Timestamp.valueOf(localDate.atTime(LocalTime.MIDNIGHT));
System.out.println(timestamp);
timestamp = Timestamp.valueOf(LocalDateTime.of(localDate, LocalTime.MIDNIGHT));
System.out.println(timestamp);
System.out.println("---Timestamp to Instant---");
instant = timestamp.toInstant();
System.out.println(instant);
}
}
---Instant--- 2019-05-15T18:30:00Z 2019-05-15T18:30:00Z 2019-05-15T18:30:00Z 2019-05-15T18:30:00Z ---Timestamp--- 2019-05-16 00:00:00.0 2019-05-16 00:00:00.0 ---Timestamp to Instant--- 2019-05-15T18:30:00Z
References
Java LocalDate to DateJava LocalDate
Java DateTimeFormatter
