Java将秒转换为时分秒

项目有个需求：计算两个时间的差值以时分秒的形式进行展示

自己简单写了一个工具类

public class TimeUtil {


    
    public static String second2Time(Long second) {
        if (second == null || second < 0) {
            return "00:00";
        }

        long h = second / 3600;
        long m = (second % 3600) / 60;
        long s = second % 60;
        String str = "";
        if (h > 0) {
            str = (h < 10 ? ("0" + h) : h) + ":";
        }
        str += (m < 10 ? ("0" + m) : m) + ":";
        str += (s < 10 ? ("0" + s) : s);
        return str;

    }
}