Java – How to add days to current date

This article shows you how to add days to the current date, using the classic java.util.Calendar and the new Java 8 date and time APIs.

1. Calendar.add

Example to add 1 year, 1 month, 1 day, 1 hour, 1 minute and 1 second to the current date.

DateExample.java

package com.favtuts.time;

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

public class AddDaysCurrentDate {

    private static final DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
    
    public static void main(String[] args) {
        useLegacyCalendarToAddDays();
    }

    static void useLegacyCalendarToAddDays() {
        Date currentDate = new Date();
        System.out.println(dateFormat.format(currentDate));

        // convert date to calendar
        Calendar c = Calendar.getInstance();
        c.setTime(currentDate);

        // manipulate date
        c.add(Calendar.YEAR, 1);
        c.add(Calendar.MONTH, 1);
        c.add(Calendar.DATE, 1); //same with c.add(Calendar.DAY_OF_MONTH, 1);
        c.add(Calendar.HOUR, 1);
        c.add(Calendar.MINUTE, 1);
        c.add(Calendar.SECOND, 1);

        // convert calendar to date
        Date currentDatePlusOne = c.getTime();

        System.out.println(dateFormat.format(currentDatePlusOne));
    }
}

Output

2022/06/05 12:36:56
2023/07/06 13:37:57

2. Java 8 Plus Minus

In Java 8, you can use the plus and minus methods to manipulate LocalDate, LocalDateTime and ZoneDateTime, see the following examples

LocalDateTimeExample.java

package com.favtuts.time;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.util.Date;

public class AddDaysCurrentDate {

    private static final String DATE_FORMAT = "yyyy/MM/dd HH:mm:ss";
    private static final DateFormat dateFormat = new SimpleDateFormat(DATE_FORMAT);
    private static final DateTimeFormatter dateFormat8 = DateTimeFormatter.ofPattern(DATE_FORMAT);

    public static void main(String[] args) {
        useJava8PlusAndMinusMethods();
    }

    static void useJava8PlusAndMinusMethods() {
        // Get current date
        Date currentDate = new Date();
        System.out.println("date : " + dateFormat.format(currentDate));

        // convert date to localdatetime
        LocalDateTime localDateTime = currentDate.toInstant().atZone(ZoneId.systemDefault()).toLocalDateTime();
        System.out.println("localDateTime : " + dateFormat8.format(localDateTime));

        // plus one
        localDateTime = localDateTime.plusYears(1).plusMonths(1).plusDays(1);
        localDateTime = localDateTime.plusHours(1).plusMinutes(2).minusMinutes(1).plusSeconds(1);

        // convert LocalDateTime to date
        Date currentDatePlusOneDay = Date.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant());

        System.out.println("\nOutput : " + dateFormat.format(currentDatePlusOneDay));
    }
}

Output

date : 2022/06/05 12:45:00
localDateTime : 2022/06/05 12:45:00

Output : 2023/07/06 13:46:01

Download Source Code

$ git clone https://github.com/favtuts/java-core-tutorials-examples

$ cd java-basic/time

References

1. Calendar JavaDoc
2. Java – How to get current date time – date() and calender()
3. Java 8 – Convert Date to LocalDate and LocalDateTime