计算时间差隔多少分钟

public static void main(String args[]) {
 String dateStart = "2016-12-26 15:00:00";
     //  String dateStop = "2016-12-26 15:25:48";
       SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
       Date d1 = null;
       Date d2 = new Date();
       try {
           d1 = format.parse(dateStart);
   
           //毫秒ms
           long diff = d2.getTime() - d1.getTime();
           
           System.out.println(diff);
   
           long diffSeconds = diff / 1000 % 60;
           long diffMinutes = diff / (60 * 1000) % 60;
           long diffHours = diff / (60 * 60 * 1000) % 24;
           long diffDays = diff / (24 * 60 * 60 * 1000);
   
           System.out.print("两个时间相差：");
           System.out.print(diffDays + " 天, ");
           System.out.print(diffHours + " 小时, ");
           System.out.print(diffMinutes + " 分钟, ");
           System.out.print(diffSeconds + " 秒.");
           if(diffMinutes>30){
            System.out.println("true");
           }else{
            System.out.println("false");
           }
   
       } catch (Exception e) {
           e.printStackTrace();
       }
   
   }