android 時間轉換

//把GMT時間轉化為Long時間public static long getLongByGMT(String gmtTime) throws ParseException{    SimpleDateFormat Gmt = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss z",Locale.ENGLISH);       return Gmt.parse(gmtTime).getTime();}//格式化顯示時間public static String displayTime(long timestamp){    SimpleDateFormat mh = new SimpleDateFormat("MM-dd HH:mm:ss");    SimpleDateFormat hm = new SimpleDateFormat("HH:mm:ss");    long currentSeconds = System.currentTimeMillis();//系統目前時間     String timeStr = null;    long currentStart = currentSeconds - currentSeconds % (24 * 60 * 60 * 1000);    long timeGap = (currentStart - timestamp) / 1000;// 與當前淩晨時間相差秒數     if (timeGap <= 0)//今天     { timeStr = hm.format(timestamp);    }    else if (timeGap > 0 && timeGap <= 24 * 60 * 60)    {timeStr = "昨天" + hm.format(timestamp);// 昨天     }    else if (timeGap > 24 * 60 * 60 && timeGap <= 2 * 24 * 60 * 60)    {timeStr = "前天" + hm.format(timestamp);// 前天     }    else    {timeStr = mh.format(timestamp);    }    return timeStr;}//根據long型的資料擷取時間值public static String getNormalTime(long value){    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss") ;    String time = format.format(new Date(value)) ;    return time;}