Calculate Future Or Past Date In Java

Introduction

This tutorial will show you how you can calculate future or past date in Java. The calculation is done on future date from a particular date to “plus a number of given days” or past date from a particular date to “minus a number of given days”.

Future or past date calculation may be required for various purposes such as to calculate the age of a person on future date or on past date.

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Prerequisites

Java 1.8+

Project Setup

The following pom.xml file can be used for maven based project:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.roytuts</groupId>
	<artifactId>java-future-or-past-date</artifactId>
	<version>0.0.1-SNAPSHOT</version>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<maven.compiler.source>11</maven.compiler.source>
		<maven.compiler.target>11</maven.compiler.target>
	</properties>

	<dependencies></dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.8.1</version>
			</plugin>
		</plugins>
	</build>
</project>

Calculate Future or Past Date

The below source code shows how you can calculate future or past date in Java.

package com.roytuts.java.future.or.past.date;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class FuturePastDateApp {

	private static final String DATE_FORMAT = "yyyy-MM-dd";

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		String date = "2015-02-25"; // date from which a next or past date will be calculated
		String futureDate = addDaysToDate(date, "280"); // get date after adding 280 days to the above date
		System.out.println("Future Date : " + futureDate + "(" + DATE_FORMAT + ")");
		String pastDate = subtractDaysFromDate(date, "30"); // get past date after subtracting 30 days from the above
															// date
		System.out.println("Past Date : " + pastDate + "(" + DATE_FORMAT + ")");
	}

	/**
	 *
	 * @param date
	 * @param days
	 * @return string
	 */
	private static String addDaysToDate(String date, String days) {
		Calendar c = Calendar.getInstance();
		DateFormat df = new SimpleDateFormat(DATE_FORMAT);

		try {
			Date myDate = df.parse(date.trim());
			c.setTime(myDate);
			c.add(Calendar.DATE, Integer.parseInt(days));
		} catch (ParseException e) {
			e.printStackTrace();
		}

		String toDate = df.format(c.getTime());

		return toDate;
	}

	/**
	 *
	 * @param date
	 * @param days
	 * @return string
	 */
	private static String subtractDaysFromDate(String date, String days) {
		Calendar c = Calendar.getInstance();
		DateFormat df = new SimpleDateFormat(DATE_FORMAT);

		try {
			Date myDate = df.parse(date.trim());
			c.setTime(myDate);
			c.add(Calendar.DATE, (Integer.parseInt(days) * -1));
		} catch (ParseException e) {
			e.printStackTrace();
		}

		String toDate = df.format(c.getTime());

		return toDate;
	}

}

Output

On executing the above Java class you will see below output:

Future Date : 2015-12-02(yyyy-MM-dd)
Past Date : 2015-01-26(yyyy-MM-dd)

Source Code

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