Commonly Used Methods in LocalDate, LocalTime and LocalDateTime Classes in Java

Java provides the three most important classes related to dates namely LocalDate, LocalTime, LocalDateTime which makes the handling of dates in Java very easy as in order to use these classes, we need to import ‘java.time’ package which is main the main API for dates, times, instants, and durations.

Illustration:

1. java.time.* 
   // To include all classes
   
2. java.time.LocalDate
   // for LocalDate
   
3. java.time.LocalDateTime 
   // for LocalDateTime
   
4. java.time.time 
   // for LocalTime

Class	Description
LocalDate	LocalDate class can hold the Date only. For example, say be it 2021-02-28
LocalTime	LocalTime class can hold the Time only. For example, say be it 19:32:25.457826
LocalDateTime	LocalDateTime class holds both the Date and Time. For example, say be it 2021-02-28T19:32:25.457826.  In this format, Before T is the date, and after T is the Time.

It is generally said considered bad practice to import all the unnecessary files of the package. Therefore, we should import only the classes which are needed. There are various methods present in these classes to handle date and time according to the class. Lets us discuss the most frequent method of LocalDate class known as now() method.

Method: now() method

The now() method of a LocalDate class used to obtain the current date from the system clock in the default time-zone. This method will return LocalDate based on the system clock with the default time-zone to obtain the current date.

Syntax:

public static LocalDate now()

Return value: This method returns the current date using the system clock and default time-zone.

Example 1:

Java

// Java Program to illustrate Commonly used methods in classes
// LocalDate, LocalTime and LocalDateTime Classes

// Importing input output classes
import java.io.*;
// Importing LocalDate, LocalTime, LocalDateTime classes
// from java.time package
import java.time.LocalDate;
import java.time.LocalTime;
import java.time.LocalDateTime;

// Main class
class GFG {

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

        // Creating instance of LocalDate class
        // using now() method
        LocalDate presentDate = LocalDate.now();

        // Print and display present date
        System.out.println(presentDate);

        // Creating instance of LocalDateTime class
        // using now() method
        LocalDateTime present = LocalDateTime.now();

        System.out.println(present);

        // Creating instance of LocalTime class
        // again using now() method
        LocalTime presentTime = LocalTime.now();

        // Print and display the current time
        System.out.println(presentTime);
    }
}

Output

2021-02-28
2021-02-28T14:16:07.181034
14:16:07.181230

We will be discussing the rest of the utility methods in the table shown below in a single code in the implementation part which is discussed further. All the classes have been discussed namely the LocalDate, LocalDateTime, LocalTime classes are immutable and all the modification method returns new object and therefore do not change the value of the current object. 

Some utility methods provided by the LocalDate class are as follows: 

Methods	Description
getDayOfMonth()	Returns the day of the month. For example, say it be 28
getDayOfWeek()	Returns the weekday. For example, say it be SUNDAY
getDayOfYear()	Returns the day w.r.t. the year. For example, say it be 59
getMonth()	Returns the name of the month. For example, say it be FEBRUARY
getMonthValue()	Returns the numeric value of the month. For example, say it be 2
isLeapYear()	Returns boolean value (true/false). For example, say it be false.
lengthOfYear()	Returns the number of days in that year. For example, say it be 365.
lengthOfMonth()	Returns the number of days in that year. For example, say ut be 28.
plusDays(numberOfDaysToBeAdded)	Returns a new date after adding the number of days to the current date.
plusMonths(numberOfMonthsToBeAdded)	Returns a new date after adding the number of months to the current date.
plusYears(numberOfYearsToBeAdded)	Returns a new date after adding the number of years to the current date.

Similar methods are available of subtracting date. minusDays(), minusMonths(), minusYears(). These functions are also available for the LocalDateTime class, adding some more related to time. Such as plusHours(), plusMinutes(), plusSeconds(), plusNanos() and many more.

Example 2:

Java

// Java Program to illustrate Commonly used methods in
// classes LocalDate, LocalTime and LocalDateTime Classes

//  Importing input output classes
import java.io.*;
// Importing java.time package to import classes
// LocalDate, LocalTime and LocalDateTime
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;

// Main class
class GFG {

    // Main driver method
    public static void main(String[] args)
    {
        // Creating object of LocalDate
        LocalDate presentDate = LocalDate.now();

        System.out.println(presentDate);

        // Creating object of LocalDateTime
        LocalDateTime present = LocalDateTime.now();

        System.out.println(present);

        // Creating object of LocalTime
        LocalTime presentTime = LocalTime.now();

        System.out.println(presentTime);

        // Implementing the LocalDate class methods
        // All methods of the table are shown below

        // Print the day of the month
        System.out.println(presentDate.getDayOfMonth());

        // Print the weekday
        System.out.println(presentDate.getDayOfWeek());

        // Print the day w.r.t. the year
        System.out.println(presentDate.getDayOfYear());

        // Print the name of the month
        System.out.println(presentDate.getMonth());

        // Print the name of the month
        System.out.println(presentDate.getMonthValue());

        // Print the boolean value (true/false)
        System.out.println(presentDate.isLeapYear());

        // Print the number of days in that year
        System.out.println(presentDate.lengthOfYear());

        // Print the
        System.out.println(presentDate.lengthOfMonth());

        // Print the new date after adding the number of
        // days to the current date.
        System.out.println(presentDate.plusDays(50));

        // Print the new date after adding the number of
        // months to the current date.
        System.out.println(presentDate.plusMonths(50));

        // Print the new date after adding the number of
        // years to the current date.
        System.out.println(presentDate.plusYears(50));

        // Similarly for the rest of them.
        System.out.println(presentDate.minusDays(50));
        System.out.println(presentDate.minusMonths(50));
        System.out.println(presentDate.minusYears(50));

        // Implementing methods which are available in
        // LocalTime and LocalDateTime

        System.out.println(present.plusHours(100));
        System.out.println(present.plusMinutes(1000));
        System.out.println(present.plusSeconds(100000));
        System.out.println(present.plusNanos(1000000));
    }
}

Output

2021-02-28
2021-02-28T14:54:21.331923
14:54:21.332156
28
SUNDAY
59
FEBRUARY
2
false
365
28
2021-04-19
2025-04-28
2071-02-28
2021-01-09
2016-12-28
1971-02-28
2021-03-04T18:54:21.331923
2021-03-01T07:34:21.331923
2021-03-01T18:41:01.331923
2021-02-28T14:54:21.332923