public class ChangeTime {

public static void main(String[] args) {

//時間總的秒數

int seconds = 30654;

//開始時間

int startHours = seconds/3600;

int startMinutes = (seconds%3600)/60;

int startSeconds = (seconds%3600)%60;

Calendar cal=Calendar.getInstance();//使用日曆類

SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//時間格式

//時間：yyyy-MM-dd HH:mm:ss

String startDateStr = cal.get(Calendar.YEAR) + "-" + (cal.get(Calendar.MONTH)+1)

+ "-" + cal.get(Calendar.DAY_OF_MONTH) + " " + startHours

+ ":" + startMinutes + ":" + startSeconds;

System.out.println("時間：" + startDateStr);

}