[java] How do I add one month to current date in Java?

In Java how can I add one month to the current date?

Use calander and try this code.

Calendar calendar = Calendar.getInstance();         
calendar.add(Calendar.MONTH, 1);
calendar.set(Calendar.DATE, calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
Date nextMonthFirstDay = calendar.getTime();
calendar.set(Calendar.DATE, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
Date nextMonthLastDay = calendar.getTime();

If you need a one-liner (i.e. for Jasper Reports formula) and don't mind if the adjustment is not exactly one month (i.e "30 days" is enough):

new Date($F{invoicedate}.getTime() + 30L * 24L * 60L * 60L * 1000L)

You can make use of apache's commons lang DateUtils helper utility class.

Date newDate = DateUtils.addMonths(new Date(), 1);

You can download commons lang jar at http://commons.apache.org/proper/commons-lang/

public class StringSplit {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        date(5, 3);
        date(5, 4);
    }

    public static String date(int month, int week) {
        LocalDate futureDate = LocalDate.now().plusMonths(month).plusWeeks(week);
        String Fudate = futureDate.toString();
        String[] arr = Fudate.split("-", 3);
        String a1 = arr[0];
        String a2 = arr[1];
        String a3 = arr[2];
        String date = a3 + "/" + a2 + "/" + a1;
        System.out.println(date);
        return date;
    }
}

Output:

10/03/2020
17/03/2020

Calendar cal = Calendar.getInstance(); 
cal.add(Calendar.MONTH, 1);
java.util.Date dt = cal.getTime();

you can use DateUtils class in org.apache.commons.lang3.time package

DateUtils.addMonths(new Date(),1);

Calendar cal = Calendar.getInstance(); 
cal.add(Calendar.MONTH, 1);

public Date  addMonths(String dateAsString, int nbMonths) throws ParseException {
        String format = "MM/dd/yyyy" ;
        SimpleDateFormat sdf = new SimpleDateFormat(format) ;
        Date dateAsObj = sdf.parse(dateAsString) ;
        Calendar cal = Calendar.getInstance();
        cal.setTime(dateAsObj);
        cal.add(Calendar.MONTH, nbMonths);
        Date dateAsObjAfterAMonth = cal.getTime() ;
    System.out.println(sdf.format(dateAsObjAfterAMonth));
    return dateAsObjAfterAMonth ;
}`

In order to find the day after one month, it is necessary to look at what day of the month it is today.

So if the day is first day of month run following code

Calendar calendar = Calendar.getInstance();

    Calendar calFebruary = Calendar.getInstance();
    calFebruary.set(Calendar.MONTH, Calendar.FEBRUARY);

    if (calendar.get(Calendar.DAY_OF_MONTH) == 1) {// if first day of month
    calendar.add(Calendar.MONTH, 1);
    calendar.set(Calendar.DATE, calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
    Date nextMonthFirstDay = calendar.getTime();
    System.out.println(nextMonthFirstDay);

    }

if the day is last day of month, run following codes.

    else if ((calendar.getActualMaximum(Calendar.DAY_OF_MONTH) == calendar.get(Calendar.DAY_OF_MONTH))) {// if last day of month
    calendar.add(Calendar.MONTH, 1);
    calendar.set(Calendar.DATE, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
    Date nextMonthLastDay = calendar.getTime();
    System.out.println(nextMonthLastDay);
    }

if the day is in february run following code

    else if (calendar.get(Calendar.MONTH) == Calendar.JANUARY
            && calendar.get(Calendar.DAY_OF_MONTH) > calFebruary.getActualMaximum(Calendar.DAY_OF_MONTH)) {// control of february

    calendar.add(Calendar.MONTH, 1);
    calendar.set(Calendar.DATE, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
    Date nextMonthLastDay = calendar.getTime();
    System.out.println(nextMonthLastDay);

    }

the following codes are used for other cases.

    else { // any day
    calendar.add(Calendar.DATE, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
    Date theNextDate = calendar.getTime();
    System.out.println(theNextDate);
    }

This method returns the current date plus 1 month.

public Date  addOneMonth()  {
        Calendar cal = Calendar.getInstance();
        cal.add(Calendar.MONTH, 1);
        return cal.getTime();
}`

    Date dateAfterOneMonth = new DateTime(System.currentTimeMillis()).plusMonths(1).toDate();

tl;dr

LocalDate::plusMonths

Example:

LocalDate.now( )
         .plusMonths( 1 );

Better to specify time zone.

LocalDate.now( ZoneId.of( "America/Montreal" )
         .plusMonths( 1 );

java.time

The java.time framework is built into Java 8 and later. These classes supplant the old troublesome date-time classes such as java.util.Date, .Calendar, & java.text.SimpleDateFormat. The Joda-Time team also advises migration to java.time.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations.

Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport and further adapted to Android in ThreeTenABP.

Date-only

If you want the date-only, use the LocalDate class.

ZoneId z = ZoneId.of( "America/Montreal" );
 LocalDate today = LocalDate.now( z );

today.toString(): 2017-01-23

Add a month.

LocalDate oneMonthLater = today.plusMonths( 1 );

oneMonthLater.toString(): 2017-02-23

Date-time

Perhaps you want a time-of-day along with the date.

First get the current moment in UTC with a resolution of nanoseconds.

Instant instant = Instant.now();

Adding a month means determining dates. And determining dates means applying a time zone. For any given moment, the date varies around the world with a new day dawning earlier to the east. So adjust that Instant into a time zone.

ZoneId zoneId = ZoneId.of( "America/Montreal" );
ZonedDateTime zdt = ZonedDateTime.ofInstant( instant , zoneId );

Now add your month. Let java.time handle Leap month, and the fact that months vary in length.

ZonedDateTime zdtMonthLater = zdt.plusMonths( 1 );

You might want to adjust the time-of-day to the first moment of the day when making this kind of calculation. That first moment is not always 00:00:00.0 so let java.time determine the time-of-day.

ZonedDateTime zdtMonthLaterStartOfDay = zdtMonthLater.toLocalDate().atStartOfDay( zoneId );

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Where to obtain the java.time classes?

• Java SE 8, Java SE 9, and later
  • Built-in.
  • Part of the standard Java API with a bundled implementation.
  • Java 9 adds some minor features and fixes.
• Java SE 6 and Java SE 7
  • Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
• Android
  • The ThreeTenABP project adapts ThreeTen-Backport (mentioned above) for Android specifically.
  • See How to use ThreeTenABP….

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

Joda-Time

Update: The Joda-Time project is now in maintenance mode. Its team advises migration to the java.time classes. I am leaving this section intact for posterity.

The Joda-Time library offers a method to add months in a smart way.

DateTimeZone timeZone = DateTimeZone.forID( "Europe/Paris" );
DateTime now = DateTime.now( timeZone );
DateTime nextMonth = now.plusMonths( 1 );

You might want to focus on the day by adjust the time-of-day to the first moment of the day.

DateTime nextMonth = now.plusMonths( 1 ).withTimeAtStartOfDay();

Java 8

LocalDate futureDate = LocalDate.now().plusMonths(1);

You can use like this;

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String d = "2000-01-30";
Date date= new Date(sdf.parse(d).getTime());
date.setMonth(date.getMonth() + 1);

(adapted from Duggu)

public static Date addOneMonth(Date date)
{
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.add(Calendar.MONTH, 1);
    return cal.getTime();
}