java计算2个日期之间相差几个月

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM"); 
        String str1 = "2017-06"; 
        String str2 = "2017-08"; 
        Calendar bef = Calendar.getInstance(); 
        Calendar aft = Calendar.getInstance(); 
        bef.setTime(sdf.parse(str1)); 
        aft.setTime(sdf.parse(str2)); 
        int result = aft.get(Calendar.MONTH) - bef.get(Calendar.MONTH); 
        int month = (aft.get(Calendar.YEAR) - bef.get(Calendar.YEAR)) * 12; 
        System.out.println(Math.abs(month + result));