How to convert Java.Util.Date to System.DateTime

Question

In Xamarin.Android, you work with both .NET and Java.

I get a return value of Java.Util.Date, I then need to input that same value as a parameter that only takes System.DateTime

This is how I currently do it

public static DateTime ConvertJavaDateToDateTime(Date date)
{
    var a = date.ToGMTString();
    var b = date.ToLocaleString();
    var c = date.ToString();
    DateTime datetime = DateTime.ParseExact(date.ToGMTString(), "dd MMM yyyy HH:mm:ss 'GMT'", CultureInfo.InvariantCulture);
    return datetime;
}

However on the first 9 days of any month, I only get 1 digit for the day, and the DateTime.ParseExact function is looking for dd (i.e. 2 digits for the day).

a is a string with value "1 Sep 2014 14:32:25 GMT"

b is a string with value "1 Sep 2014 16:32:25"

c is a string with value "Mon Sep 01 16:32:25 EET 2014"

I wish I could find a simple, quick, reliable and consistent solution for this problem :D

What is the value of `date.ToGMTString()` exactly? Did you try with `d` specifier also? — Soner Gönül, Jul 04 '14 at 13:06
@SonerGönül Ive updated the question with more details, no didn't try with just a d, cause I'm assuming it won't work with double-digit days, such as 10, 11, etc — Mohamed Heiba, Jul 04 '14 at 13:11
@chrylis can you elaborate please ? how do I use the long timestamp to convert java.util.date to system.datetime — Mohamed Heiba, Jul 04 '14 at 13:11
@Dv_MH [`d` specifier](http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx#dSpecifier) represents from `1` to `31`. — Soner Gönül, Jul 04 '14 at 13:19
I don't know; I don't use .NET. See if the docs for DateTime have a constructor from a Unix timestamp? — chrylis -cautiouslyoptimistic-, Jul 04 '14 at 13:20

score 16 · Accepted Answer · edited May 23 '17 at 11:46

16

java.util.Date has a getTime() method, which returns the date as a millisecond value. The value is the number of milliseconds since Jan. 1, 1970, midnight GMT.

With that knowledge, you can construct a System.DateTime, that matches this value like so:

public DateTime FromUnixTime(long unixTimeMillis)
{
    var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
    return epoch.AddMilliseconds(unixTimeMillis);
}

(method taken from this answer)

edited May 23 '17 at 11:46

Community

1
1

answered Jul 04 '14 at 13:35

Dennis

2,119
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amazing, let me try that – Mohamed Heiba Jul 04 '14 at 13:36
I get a System.ArgumentOutOfRangeException: Argument is out of range at the line where i .AddSeconds – Mohamed Heiba Jul 04 '14 at 13:49
I see, that might be confusing: The method `AddSeconds()` takes seconds of course, but `getTime()` gives you milliseconds. Can you try to use `epoch.AddMilliseconds()` instead? I'll edit my answer. – Dennis Jul 04 '14 at 14:12

score 1 · Answer 2 · edited Aug 16 '18 at 17:41

1

Do this:

public DateTime ConvertDateToDateTime(Date date)
{
    SimpleDateFormat dateFormat = new SimpleDateFormat("YYYY-MM-dd hh:mm:ss");
    String dateFormated = dateFormat.format(date);

   return new DateTime(dateFormated);
}

edited Aug 16 '18 at 17:41

m4tt1mus

1,642
14
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answered Jul 04 '14 at 13:32

Cícero Moura

2,027
1
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36

cant use Joda Time in .NET – Mohamed Heiba Jul 04 '14 at 13:33
looks amazing let me try that – Mohamed Heiba Jul 04 '14 at 13:42

Native · Answer 3 · 2014-07-04T13:26:41.133

0

I'll update my answer, since you've changed the question.

you can use a long to hold the milliseconds and than convert the milliseconds to ticks(x10000) and create a new DateTime

Date date = new Date();
Long milliseconds = date.getTime();
Long ticks = milliseconds * 10000
DateTime datetime = DateTime(ticks);

edited Jul 04 '14 at 13:26

answered Jul 04 '14 at 13:13

Native

157
12

I could but it that a reliable and consistent solution ? – Mohamed Heiba Jul 04 '14 at 13:14
thanks a lot, sounds very promising, let me try that – Mohamed Heiba Jul 04 '14 at 13:27
1

Ok it works well, but the year is wrong, it says year {01/09/0045 14:32:25} – Mohamed Heiba Jul 04 '14 at 13:36
That's odd. What is the date value that you are passing? also, you should check these out:[Ticks per millisecond](http://msdn.microsoft.com/en-us/library/system.timespan.tickspermillisecond.aspx?cs-save-lang=1&cs-lang=vb#code-snippet-2) and [DateTime](http://msdn.microsoft.com/en-us/library/z2xf7zzk(v=vs.110).aspx) – Native Jul 04 '14 at 13:48

score 0 · Answer 4 · answered Feb 16 '17 at 16:08

0

I had this problem when authenticating with Facebook to receive the Expire time for the token. The solution was to do this:

var convertedTime = new DateTime(1970,1,1,0,0,0,DateTimeKind.Utc).AddMilliseconds(MyJavaUtil.Date.Time);

answered Feb 16 '17 at 16:08

Marcus Follrud

36
3

score 0 · Answer 5 · answered Aug 14 '20 at 08:58

0

I used this:

DateTimeOffset.FromUnixTimeMilliseconds(date.Time - (date.TimezoneOffset * 60 * 1000)).DateTime;

To incorporate the timezone offset into my date.

answered Aug 14 '20 at 08:58

Kes Walker

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Polyariz · Answer 6 · 2021-06-14T11:57:44.603

0

In my case, only this code works correctly:

public static DateTime NativeDateToDateTime(Java.Util.Date date)
{ 
    SimpleDateFormat dateFormat = new SimpleDateFormat("YYYY-MM-dd HH:mm:ss");
    string dateFormated = dateFormat.Format(date);
    
    return DateTimeOffset.Parse(dateFormated, null, DateTimeStyles.None).DateTime; 
}

edited Jun 14 '21 at 11:57

answered Jun 14 '21 at 07:31

Polyariz

534
1
7
17

score -1 · Answer 7 · answered Jul 04 '14 at 13:25

-1

It is not tested but try with Calendar methods

public static String  ConvertJavaDateToDateTime(Date date)
{
     Calendar c = new GregorianCalendar();
        c.setTime(date);        
        System.out.println(c.getTime());
      return c.getTime();
}

Prints:

Tue Aug 06 00:00:00 EDT 2013

answered Jul 04 '14 at 13:25

Sandeep

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I need to get a DateTime value not a string – Mohamed Heiba Jul 04 '14 at 13:33

score -2 · Answer 8 · answered Jul 04 '14 at 13:39

You can try with this also

public DateTime dateAndTimeToDateTime(java.sql.Date date, java.sql.Time time) {
    String myDate = date + " " + time;
    SimpleDateFormat sdf = new SimpleDateFormat("dd MMM yyyy HH:mm:ss 'GMT'");
    java.util.Date utilDate = new java.util.Date();
    try {
        utilDate = sdf.parse(myDate);
    } catch (ParseException pe){
        pe.printStackTrace();
    }
    DateTime dateTime = new DateTime(utilDate);

    return dateTime;
}

How to convert Java.Util.Date to System.DateTime

8 Answers8