Java tutorial
//package com.java2s; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Locale; public class Main { public static String millisToStringFilename(long millis, String pattern) { String dateStr = millisToStringDate(millis, pattern); return dateStr.replaceAll("[- :]", "_"); } public static String millisToStringDate(long millis, String pattern) { SimpleDateFormat format = new SimpleDateFormat(pattern, Locale.getDefault()); return format.format(new Date(millis)); } }