How to convert currentTimeMillis to a date in Java?

Question

I have milliseconds in certain log file generated in server, I also know the locale from where the log file was generated, my problem is to convert milliseconds to date in specified format. The processing of that log is happening on server located in different time zone. While converting to "SimpleDateFormat" program is taking date of the machine as such formatted date do not represent correct time of the server. Is there any way to handle this elegantly ?

long yourmilliseconds = 1322018752992l;
        //1322018752992-Nov 22, 2011 9:25:52 PM 

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss,SSS",Locale.US);

GregorianCalendar calendar = new GregorianCalendar(TimeZone.getTimeZone("US/Central"));
calendar.setTimeInMillis(yourmilliseconds);

System.out.println("GregorianCalendar -"+sdf.format(calendar.getTime()));

DateTime jodaTime = new DateTime(yourmilliseconds, 
                    DateTimeZone.forTimeZone(TimeZone.getTimeZone("US/Central")));
DateTimeFormatter parser1 = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss,SSS");

System.out.println("jodaTime "+parser1.print(jodaTime));

Output:

Gregorian Calendar -2011-11-23 08:55:52,992
jodaTime 2011-11-22 21:25:52,992

Answer 1

You may use java.util.Date class and then use SimpleDateFormat to format the Date.

Date date=new Date(millis);

We can use java.time package (tutorial) - DateTime APIs introduced in the Java SE 8.

var instance = java.time.Instant.ofEpochMilli(millis);
var localDateTime = java.time.LocalDateTime
                        .ofInstant(instance, java.time.ZoneId.of("Asia/Kolkata"));
var zonedDateTime = java.time.ZonedDateTime
                            .ofInstant(instance,java.time.ZoneId.of("Asia/Kolkata"));

// Format the date

var formatter = java.time.format.DateTimeFormatter.ofPattern("u-M-d hh:mm:ss a O");
var string = zonedDateTime.format(formatter);