获取两个日期间隔的月数

public static int getMonthDiff(Date d1, Date d2) {
        Calendar c1 = Calendar.getInstance();
        Calendar c2 = Calendar.getInstance();
        c1.setTime(d1);
        c2.setTime(d2);
        int year1 = c1.get(Calendar.YEAR);
        int year2 = c2.get(Calendar.YEAR);
        int month1 = c1.get(Calendar.MONTH);
        int month2 = c2.get(Calendar.MONTH);
        int day1 = c1.get(Calendar.DAY_OF_MONTH);
        int day2 = c2.get(Calendar.DAY_OF_MONTH);
        // 获取年的差值 
        int yearInterval = year1 - year2;
        // 如果 d1的 月-日 小于 d2的 月-日 那么 yearInterval-- 这样就得到了相差的年数
        if (month1 < month2 || month1 == month2 && day1 < day2) {
            yearInterval--;
        }
        // 获取月数差值
        int monthInterval = (month1 + 12) - month2;
        if (day1 < day2) {
            monthInterval--;
        }
        monthInterval %= 12;
        int monthsDiff = Math.abs(yearInterval * 12 + monthInterval);
        return monthsDiff;
    }

public static void main(String[] args) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
        try {
            Date date1 = sdf.parse("20200731");
            Date date2 = sdf.parse("20210630");
            int i = getMonthDiff(date1,date2);
            System.out.println(i);
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }