Calendar cal=Calendar.getInstance(TimeZone.getTimeZone("GMT+12:00"));
        String DATE_FORMAT="yyyy-MM-dd HH:mm:ss";
        java.text.SimpleDateFormat sdf=new java.text.SimpleDateFormat(DATE_FORMAT);
        sdf.setTimeZone(TimeZone.getTimeZone("GMT+12:00"));
        System.out.println(sdf.format(cal.getTime()));

北京時間為GMT+08:00
以上代碼得到GMT+12:00的時間,