Java. Calculating the elapsed years, months, and days between two dates

Question:

Good afternoon. Date intervals are given, for example: 01/28/2009 – 03/05/2013. The task is to calculate the exact number of full years, months and days in this interval. Tell me how to do this?

I just find the number of days like this

    Date startDate = new SimpleDateFormat("dd.MM.yyyy").parse(s1);
    Date endDate = new SimpleDateFormat("dd.MM.yyyy").parse(s2);

    Calendar calendarStart = Calendar.getInstance();
    calendarStart.setTimeInMillis(startDate.getTime());

    Calendar calendarEnd = Calendar.getInstance();
    calendarEnd.setTimeInMillis(endDate.getTime());

    long difference = calendarEnd.getTimeInMillis() - calendarStart.getTimeInMillis();
    long days = difference /(24* 60 * 60 * 1000);

    System.out.println(days);

The result should be presented as: Years: 7, Months: 5, Days: 10

Answer:

It's pretty straightforward using the classes in the java.time.* Package (in Java 8 and newer):

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd.MM.yyyy");
LocalDate startDate = LocalDate.parse("28.01.2009", formatter);
LocalDate endDate = LocalDate.parse("05.03.2013", formatter);
Period period = Period.between(startDate, endDate);
System.out.println(period.getYears());      // 4
System.out.println(period.getMonths());     // 1
System.out.println(period.getDays());       // 5