java TimeZone 時區

 String tzId = "America/Los_Angeles";
	        // String tzId = TimeZone.getDefault().getID();
	        TimeZone tz = TimeZone.getTimeZone(tzId);
	        DateFormat df = DateFormat.getInstance();
	        df.setTimeZone(tz);
	        String date = df.format(new Date());
	        System.out.println(date);

	        String[] avaIds = TimeZone.getAvailableIDs();
	        for (int i = 0; i < avaIds.length; i++) {
	            int offset = TimeZone.getTimeZone(avaIds[i]).getRawOffset();
	            System.out.println(i+"  "+avaIds[i]+" "+offset / (3600 * 1000) + "\t");
	        }


可以用這個時區來生成隨機id
TimeZone tz = TimeZone.getTimeZone("ETC/GMT-8");
		TimeZone.setDefault(tz);
		SimpleDateFormat format = new SimpleDateFormat("HHmmssSS");