关于时间函数

Question

Date d = new Date();
        Calendar calendar = new GregorianCalendar();
        calendar.setTime(d);    
        System.out.println("ERA: " + calendar.get(Calendar.ERA));
        System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
        System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
        System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
        System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
        System.out.println("DATE: " + calendar.get(Calendar.DATE));
        System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
        System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
        System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
        System.out.println("DAY_OF_WEEK_IN_MONTH: "
                        + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
        System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
        System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
        System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
        System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
        System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
        System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
        System.out.println("ZONE_OFFSET: "
                        + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000)));
        System.out.println("DST_OFFSET: "
                        + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000)));
        
        System.out.println("Current Time, with hour reset to 3");
        calendar.clear(Calendar.HOUR_OF_DAY); // so doesn't override
        calendar.set(Calendar.HOUR, 3);
        System.out.println("ERA: " + calendar.get(Calendar.ERA));
        System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
        System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
        System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
        System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
        System.out.println("DATE: " + calendar.get(Calendar.DATE));
        System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
        System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
        System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
        System.out.println("DAY_OF_WEEK_IN_MONTH: "
                        + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
        System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
        System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
        System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
        System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
        System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
        System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
        System.out.println("ZONE_OFFSET: "
            + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000))); // in hours
        System.out.println("DST_OFFSET: "
            + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000))); // in hours

Answer 1

  public java.util.Date getCurrentDate()
  {
      return new java.util.Date(System.currentTimeMillis());
  }

Answer 2

month 一月是0
这样一下
System.out.println("MONTH: " + (1 + calendar.get(Calendar.MONTH)));

Answer 3

public static long java.lang.System.currentTimeMillis()
或
java.util.Calendar.getInstance().getTime()