Java – How to add days to current date

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.mkyong.time;

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

public class DateExample {

    private static final DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");

    public static void main(String[] args) {

        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));

    }

}

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Output

2016/11/10 17:11:48
2017/12/11 18:12:49

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.mkyong.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 LocalDateTimeExample {

    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) {

		// 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));

    }

}

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Output

date : 2016/11/10 17:40:11
localDateTime : 2016/11/10 17:40:11

Output : 2017/12/11 18:41:12

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