java.time.LocalDateTime Class in Java

java.time.LocalDateTime class, introduced in Java 8, represents a local date-time object without timezone information. The LocalDateTime class in Java is an immutable date-time object that represents a date in the yyyy-MM-dd-HH-mm-ss.zzz format. It implements the ChronoLocalDateTime interface and inherits the object class.

Wherever we need to represent time without a timezone reference, we can use the LocalDateTime instances. LocalDateTime, for example, can be used to start batch jobs in any application. Jobs will be run at a fixed time in the timezone in which the server is located. Note LocalDateTime instances are immutable and thread. 

Syntax: Class declaration

public final class LocalDateTime 

extends Object 

implements Temporal, TemporalAdjuster, ChronoLocalDateTime<LocalDate>, Serializable

Methods of this class are as follows:

Method	Description
format()	It is used to format this date-time using the specified formatter.
get()	It is used to get the value of the specified field from this date-time as an int.
minusMinutes()	Returns a copy of this LocalDateTime with the specified number of minutes subtracted.
minusYears()	Returns a copy of this LocalDateTime with the specified number of years subtracted.
minusDays()	Returns a copy of this LocalDateTime with the specified number of days subtracted.
now()	It is used to obtain the current date-time from the system clock in the default time zone.
plusHours()	Returns a copy of this LocalDateTime with the specified number of hours added.
plusYears()	Returns a copy of this LocalDateTime with the specified number of years added.
plusDays()	Returns a copy of this LocalDateTime with the specified number of days added.

Some more methods to modify local time are as follows in LocalDateTime can be used to get to a new localdatetime instance relative to an existing localdatetime instance. They are namely as follows:

plusYears(), plusMonths(), plusDays(), plusHours(), plusMinutes(), plusSeconds(), plusNanos(), minusYears(), minusMonths(), minusDays(), minusHours(), minusMinutes(), minusSeconds(), minusNanos()

Examples 1:

Java

// Java Program to illustrate LocalDateTime Class of java.time package

// Importing LocalDateTime class from java.time package
import java.time.LocalDateTime;

// Main class for LocalDateTime
public class GFG {

    // Main driver method
    public static void main(String[] args)
    {
        // Creating an object of LocalDateTime class
        // in the main() method
        LocalDateTime now = LocalDateTime.now();

        // Print statement
        System.out.println(now);

        // Adding 1 year, 1 month, 1 week and 1 day
        LocalDateTime localDateTime1 = now.plusYears(1)
                                           .plusMonths(1)
                                           .plusWeeks(1)
                                           .plusDays(1);
        // Print statement
        System.out.println(localDateTime1);

        // Subtracting 1 year, 1 month, 1 week and 1 day
        LocalDateTime localDateTime2
            = localDateTime1.minusYears(1)
                  .minusMonths(1)
                  .minusWeeks(1)
                  .minusDays(1);
        // Print statement
        System.out.println(localDateTime2);

        // Adding 1 hour, 1 minute, 1 second and 100
        // nanoseconds
        LocalDateTime localDateTime3
            = localDateTime2.plusHours(1)
                  .plusMinutes(1)
                  .plusSeconds(1)
                  .plusNanos(100);
        // Print statement
        System.out.println(localDateTime3);

        // Subtracting 1 hour, 1 minute, 1 second and 100
        // nanoseconds
        LocalDateTime localDateTime4
            = localDateTime3.minusHours(1)
                  .minusMinutes(1)
                  .minusSeconds(1)
                  .minusNanos(100);
        // Print statement
        System.out.println(localDateTime4);
    }
}

Output:

Example 2: Creating a specified time

Java

// Java Program to illustrate LocalDateTime Class
// of java.time package by creating specific time

// Importing required classes from resp packages
import java.time.*;
import java.time.format.*;

// main class
class GFG {

    // Main driver method
    public static void main(String[] args)
    {

        // Milliseconds
        LocalDateTime localDateTime1 = LocalDateTime.of(
            2021, 04, 24, 14, 33, 48, 123456789);
        // Print statement
        System.out.println(localDateTime1);

        // Month
        LocalDateTime localDateTime2 = LocalDateTime.of(
            2021, Month.APRIL, 24, 14, 33, 48, 123456789);
        // Print statement
        System.out.println(localDateTime2);

        // Seconds
        LocalDateTime localDateTime3 = LocalDateTime.of(
            2021, Month.APRIL, 24, 14, 33, 48);
        // Print statement
        System.out.println(localDateTime3);

        // Minutes
        LocalDateTime localDateTime4 = LocalDateTime.of(
            2021, Month.APRIL, 24, 14, 33);
        // Print statement
        System.out.println(localDateTime4);

        // Local date + Local time
        LocalDate date = LocalDate.of(2021, 04, 24);
        LocalTime time = LocalTime.of(10, 34);

        LocalDateTime localDateTime5
            = LocalDateTime.of(date, time);
        // Print statement
        System.out.println(localDateTime5);
    }
}

Output:

Example 3: Format LocalDateTime to string

To format a local time to the desired string representation, use the LocalDateTime.format(DateTimeFormatter) method.

Java

// Java Program to illustrate LocalDateTime Class by
// Formatting LocalDateTime to string

// Importing all classes from java.time package
import java.time.LocalDateTime;
import java.time.format.*;
import java.util.*;

// Main class
class GFG {

    // Main driver method
    public static void main(String[] args)
    {

        // Creating an object of DateTimeFormatter class
        DateTimeFormatter formatter
            = DateTimeFormatter.ofPattern(
                "yyyy-MM-dd HH:mm:ss a");

        // Creating an object of LocalDateTime class
        // and getting local date and time using now()
        // method
        LocalDateTime now = LocalDateTime.now();

        // Formatting LocalDateTime to string
        String dateTimeString = now.format(formatter);

        // Print and Display
        System.out.println(dateTimeString);
    }
}

Output:

Note: In order to parse a string to LocalDateTime, convert time in a string to a local time instance, the LocalDateTime class has two overloaded parse() methods.

• parse(CharSequence text)
• parse(CharSequence text, DateTimeFormatter formatter)