计算两个日期相差月数，精确到天

 /**
     * 计算两个日期的月份相差数
     *
     * @param begin 开始日期
     * @param end 结束日期
     * @return 相差月数，精确到天
     */
    public static int minusMonth(Date begin, Date end) {
        Calendar calendarBegin = Calendar.getInstance();
        calendarBegin.setTime(begin);
        Calendar calendarEnd = Calendar.getInstance();
        calendarEnd.setTime(end);

        int yearBegin = calendarBegin.get(Calendar.YEAR);
        int monthBegin = calendarBegin.get(Calendar.MONTH);
        int dayOfMonthBegin = calendarBegin.get(Calendar.DAY_OF_MONTH);
        int yearEnd = calendarEnd.get(Calendar.YEAR);
        int monthEnd = calendarEnd.get(Calendar.MONTH);
        int dayOfMonthEnd = calendarEnd.get(Calendar.DAY_OF_MONTH);

        int years = yearEnd - yearBegin;
        int months = monthEnd - monthBegin;
        // 月数偏移量，日期比较，若大则正好，若小则月数-1
        int monthOffset = dayOfMonthEnd >= dayOfMonthBegin ? 0 : -1;
        return years * 12 + months + monthOffset;
    }