java获取时间

public static void main(String[] args)
    {
        int days=30;
  Calendar cal1=Calendar.getInstance();
        //+30代表300天后这个时候的时间
  Calendar cal2=Calendar.getInstance();
        cal1.add(Calendar.DAY_OF_YEAR,0);
        cal2.add(Calendar.DAY_OF_YEAR, days);
        SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String nowtime1=sdf.format(cal1.getTime());
        String nowtime2=sdf.format(cal2.getTime());
        System.out.println(nowtime1);
        System.out.println(nowtime2);
    }