java 獲取兩個日期相差的月份

前兩天要用到獲取兩個時間之間的月份差，今天總結下。

 /**
     * 獲取連個日期之間相差的月份
     * @param startDate
     * @param endDate
     * @return
     * @throws ParseException
     */
    private static List getMonth(String startDate, String endDate) throws ParseException {
        List list = new ArrayList();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");
        Calendar c1 = Calendar.getInstance();
        Calendar c2 = Calendar.getInstance();
        c1.setTime(sdf.parse(startDate));
        c2.setTime(sdf.parse(endDate));
        int  year = c2.get(Calendar.YEAR) - c1.get(Calendar.YEAR);
        int month = c2.get(Calendar.MONTH)+year*12 - c1.get(Calendar.MONTH);
        for(int i = 0;i<=month;i++){
            c1.setTime(sdf.parse(startDate));
            c1.add(c1.MONTH, i);
            list.add(sdf.format(c1.getTime()));
        }
        return list;
    }

當前月份向前或向後推。

     /**
     * 計算前幾個月/後幾個月
     * @param date
     * @param flag
     * @return
     * @throws ParseException
     */
    private static List getMonth(String date, boolean flag, int num) throws ParseException{
        List list = new ArrayList();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");
        Calendar c = Calendar.getInstance();
        c.setTime(sdf.parse(date));
        for(int i = 0;i<num;i++){
            c.setTime(sdf.parse(date));
            if(flag){
                c.add(c.MONTH, i);
            }else{
                c.add(c.MONTH, i+1-num);
            }
            list.add(sdf.format(c.getTime()));
        }
        return list;
    }

方法調用

 public static void main(String[] args) {
        try {
            List list = getMonth("2018-11","2019-10");
            System.out.println(list);
            List list1 = getMonth("2020-01",true,3);
            System.out.println(list1);
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }

結果輸出