计算两个日期相隔月份

/**
     * 
     * 比较日期月份
     * @param start 开始日期
     * @param end 结束日期
     * @return Integer
     */
    public static Integer diffMonth(Date start, Date end) {
        if (start == null || end == null) {
            return null;
        }
        Calendar cStart = Calendar.getInstance();
        cStart.setTime(start);
        Calendar cEnd = Calendar.getInstance();
        cEnd.setTime(end);
        int month = cEnd.get(Calendar.MONTH) - cStart.get(Calendar.MONTH);
        int year = cEnd.get(Calendar.YEAR) - cStart.get(Calendar.YEAR);
        return year * 12 + month;
    }