如何将时间戳转换为自 Unix 纪元以来的秒数?我只是将时间戳转换为UTC时间戳。现在我想将此时间戳转换为秒。
Calendar currenttime = Calendar.getInstance();
System.out.println("current: "+currenttime.getTime());
    //TIMESTAMP UTC/GMT
    TimeZone z = currenttime.getTimeZone();
    int offset = z.getRawOffset();
    if(z.inDaylightTime(new Date())){
        offset = offset + z.getDSTSavings();
    }
    int offsetHrs = offset / 1000 / 60 / 60;
    int offsetMins = offset / 1000 / 60 % 60;
    currenttime.add(Calendar.HOUR_OF_DAY, (-offsetHrs));
    currenttime.add(Calendar.MINUTE, (-offsetMins));
    System.out.println("GMT CURRENT TIME: "+currenttime);