JAVA将十位时间戳格式化为日期Date类型

public static String timeStamp2Date(String seconds,String format) {
if(seconds == null || seconds.isEmpty() || seconds.equals("null")){
return "";
}
if(format == null || format.isEmpty()) format = "yyyy-MM-dd HH:mm:ss";
SimpleDateFormat sdf = new SimpleDateFormat(format);
return sdf.format(new Date(Long.valueOf(seconds+"000")));
}

public static String getTimeStr(Integer time) {
Integer hour = time/(60*60);
Integer minute = (time-hour*3600)/60;
Integer seconds = time-hour*3600-minute*60;
StringBuffer sb = new StringBuffer();
if(hour.toString().length() == 1) {
sb.append("0"+hour);
} else {
sb.append(hour);
}
sb.append(":");
if(minute.toString().length() == 1) {
sb.append("0" + minute);
} else {
sb.append(minute);
}
sb.append(":");
if(seconds.toString().length() == 1) {
sb.append("0" + seconds);
} else {
sb.append(seconds);
}

return sb.toString();
}