JAVA將秒的總和轉換成時分秒的格式

public static void main(String[] args) {
String str = "221";
int seconds = Integer.parseInt(str);
int temp=0;
StringBuffer sb=new StringBuffer();
temp = seconds/3600;
sb.append((temp<10)?"0"+temp+":":""+temp+":");

temp=seconds%3600/60;
sb.append((temp<10)?"0"+temp+":":""+temp+":");

temp=seconds%3600%60;
sb.append((temp<10)?"0"+temp:""+temp);

System.out.println(sb.toString());

}