Opposite of subtracting months from a java date, this example will show how to add months to a date using java Calendar.add, java 8 date time api, joda’s DateTime.plusMonths and apache commons DateUtils.addMonths. Assuming players get a vacation after the super bowl, we will set the date which it occurred and then add one month to represent a vacation of sipping fruity drinks in Mexico.
Straight up Java
@Test
public void add_months_to_date_in_java () {
Calendar superBowlXLV = Calendar.getInstance();
superBowlXLV.set(2011, 1, 6, 0, 0);
Calendar sippinFruityDrinksInMexico = Calendar.getInstance();
sippinFruityDrinksInMexico.setTimeInMillis(superBowlXLV.getTimeInMillis());
sippinFruityDrinksInMexico.add(Calendar.MONTH, 1);
SimpleDateFormat dateFormatter = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss z");
logger.info(dateFormatter.format(superBowlXLV.getTime()));
logger.info(dateFormatter.format(sippinFruityDrinksInMexico.getTime()));
assertTrue(sippinFruityDrinksInMexico.after(superBowlXLV));
}
Output
02/06/2011 00:00:49 CST
03/06/2011 00:00:49 CST
Java 8 Date and Time API
Java 8 LocalDateTime.plusMonths will return a copy of the LocalDateTime with the specified number of months added.
@Test
public void add_months_to_date_in_java8() {
LocalDateTime superBowlXLV = LocalDateTime.of(2011, Month.FEBRUARY, 6,
0, 0);
LocalDateTime sippinFruityDrinksInMexico = superBowlXLV.plusMonths(1);
java.time.format.DateTimeFormatter formatter = java.time.format.DateTimeFormatter
.ofPattern("MM/dd/yyyy HH:mm:ss S");
logger.info(superBowlXLV.format(formatter));
logger.info(sippinFruityDrinksInMexico.format(formatter));
assertTrue(sippinFruityDrinksInMexico.isAfter(superBowlXLV));
}
Output
02/06/2011 00:00:00 0
03/06/2011 00:00:00 0
Joda Time
Joda DateTime.plusMonths will return a copy the DateTime plus the specified number of months.
@Test
public void add_months_to_date_in_java_joda () {
DateTime superBowlXLV = new DateTime(2011, 2, 6, 0, 0, 0, 0);
DateTime sippinFruityDrinksInMexico = superBowlXLV.plusMonths(1);
DateTimeFormatter fmt = DateTimeFormat.forPattern("MM/dd/yyyy HH:mm:ss z");
logger.info(superBowlXLV.toString(fmt));
logger.info(sippinFruityDrinksInMexico.toString(fmt));
assertTrue(sippinFruityDrinksInMexico.isAfter(superBowlXLV));
}
Output
02/06/2011 00:00:00 CST
03/06/2011 00:00:00 CST
Apache Commons
Apache commons DateUtils.addMonths will adds a number of months to the date returning a new object.
@Test
public void add_months_to_date_in_java_apachecommons () {
Calendar superBowlXLV = Calendar.getInstance();
superBowlXLV.set(2011, 1, 6, 0, 0);
Date sippinFruityDrinksInMexico = DateUtils.addMonths(superBowlXLV.getTime(), 1);
SimpleDateFormat dateFormatter = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss z");
logger.info(dateFormatter.format(superBowlXLV.getTime()));
logger.info(dateFormatter.format(sippinFruityDrinksInMexico));
assertTrue(sippinFruityDrinksInMexico.after(superBowlXLV.getTime()));
}
Output
02/06/2011 00:00:11 CST
03/06/2011 00:00:11 CST