时间日期的转换

Posted 2022-11-25 zlfxy

毫秒，日期之间的转换

(1)毫秒转换为日期

public static void main(String[] args) 
        long a = Long.parseLong("135707832866");
        Date date = new Date(a);
        DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        System.err.println(dateFormat.format(date));

    

public static void main(String[] args) 
      DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
      long now = System.currentTimeMillis();
      Calendar calendar = Calendar.getInstance();
      calendar.setTimeInMillis(now);
      System.out.println(now + " = " + formatter.format(calendar.getTime()));

 (2) 日期转换为毫秒 两个日期想减得到天数

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String start = "2011-09-20 12:30:45";
        String end = "2011-10-20 6:30:00";
        try 
            // 得到毫秒数
            long timeStart = sdf.parse(start).getTime();
            long timeEnd = sdf.parse(end).getTime();
            // 两个日期想减得到天数
            long dayCount = (timeEnd - timeStart) / (24 * 3600 * 1000);
            System.out.println(dayCount);
         catch (ParseException e) 
            e.printStackTrace();