@Test
public void testTwoDateInterval() {

    int year1 = 2018, month1 = 9, day1 = 3;
    int year2 = 2016, month2 = 12, day2 = 12;
    int date1Days = DataUtil.getIntervalDays(year1, month1, day1);
    int date2Days = DataUtil.getIntervalDays(year2, month2, day2);
    System.out.println("date1Days: " + date1Days);
    System.out.println("date2Days: " + date2Days);
    int intervalDays = date1Days - date2Days;
    System.out.println("intervalDays: " + (intervalDays >= 0 ? intervalDays : -intervalDays));
}