How To Add Weeks To Local date-time In Java 8 and Higher Versions?

LocalDateTime class is used to create dates and times in Java. This class contains several methods to perform date and time-related operations.

In this article, we will learn to add weeks to the date-time in Java,

To add weeks, we can use plusWeeks() method of this class that returns a copy of the local date-time object after adding the specified weeks.

For example, if we want to add 1 week to "2022-03-14T17:28:13.048999208", then the result will be "2022-03-21T17:28:13.048999208".

This method was added to Java 8 date-time API. So, can be used in Java 8 and higher versions such as Java 11, Java 17, etc.

Let's understand with the running examples.

Adding Weeks to Date-Time in Java

In this example, we are adding 1 week to the date by using the plusWeeks() method but first, we created a date-time object by using the parse() method and then used the method.

/* 
 *  Code example to add weeks to local date time in Java
 */
import java.time.LocalDateTime;
public class JExercise {
	public static void main(String[] args) {		

		// String date is given
		String strDate = "2022-03-14T17:28:13.048999208";
		// parse the date into date time
		LocalDateTime date = LocalDateTime.parse(strDate);

		// Displaying date and time
		System.out.println("Date : "+date);

		// Add 1 week to the date
		LocalDateTime newDate = date.plusWeeks(1); 

		// Display result
		System.out.println("New Date : "+newDate);
	}
}

Output:

Date : 2022-03-14T17:28:13.048999208
New Date : 2022-03-21T17:28:13.048999208
 

Now, let's see its signature

public LocalDateTime plusWeeks(long weeks)

Package Name: java.time;

Class Name: LocalDateTime

Return Value: It returns a copy of localdatetime after adding the specified number of weeks, not null.

Parameters: It takes a single long type value. It may be negative.

Exceptions: It throws a DateTimeException if the result exceeds the supported(either MIN or MAX) date range.

Version: Since 1.8

Let's see some more examples.

Adding Weeks to the Current Date-Time in Java

Here, we used the now() method of the LocalDateTime class to get the current date-time and then used the plusWeeks() method to add 1 week to it. See the below Java code.

/* 
 *  Code example to add weeks to local date time in Java
 */
import java.time.LocalDateTime;
public class JExercise {
	public static void main(String[] args) {		

		// Current date and time
		LocalDateTime date = LocalDateTime.now();

		// Displaying date and time
		System.out.println("Date : "+date);

		// Add 1 week to the date
		LocalDateTime newDate = date.plusWeeks(1); 

		// Display result
		System.out.println("New Date : "+newDate);
	}
}

Output:

Date : 2022-03-15T12:01:23.828421713
New Date : 2022-03-22T12:01:23.828421713

Subtracting Weeks from Date-Time in Java

The plusWeeks() method accepts a negative value as an argument as well. It works the opposite in the case of a negative argument which means it minus weeks from date-time rather than adding. 

/* 
 *  Code example to add weeks to local date time in Java
 */
import java.time.LocalDateTime;
public class JExercise {
	public static void main(String[] args) {		

		// Current date and time
		LocalDateTime date = LocalDateTime.now();

		// Displaying date and time
		System.out.println("Date : "+date);

		// Add 2 weeks to the date
		LocalDateTime newDate = date.plusWeeks(-2); 

		// Display result
		System.out.println("New Date : "+newDate);
	}
}

Output:

Date : 2022-03-15T12:02:05.947599532
New Date : 2022-03-01T12:02:05.947599532
 

Single Line Solution - Final Shot

Use this code to get results in a single line of code. If you are a beginner, skip this code.

LocalDateTime.now().plusWeeks(5);

This code returns a LocalDateTime object after adding 5 weeks to the current date-time. You just replace the value with your input and get the result instantly.