//本地時區與GMT格林威治标準時間的偏移量(北京是東八區 相差的毫秒數是28800000)
TimeZone.getDefault().getRawOffset();
Date nowTime = new Date();
System.out.println( "現在的時間: " + nowTime);
SimpleDateFormat matter1 = new SimpleDateFormat( " 'time ': yyyy-MM-dd HH:mm:ss z ");
matter1.setTimeZone(TimeZone.getTimeZone( "GMT "));
System.out.println( "現在的時間: " + matter1.format(nowTime));
/**
*matter1.getCalendar().getTime().getTime()+(long)TimeZone.getDefault().getRawOffset() == nowTime.getTime();
* 成立
*/