Passing java dates timestamp to Javascript's date object

[Fawad Ali]

Hi All:
I have a strange problem. I get a timestamp from java date and pass it to a javascript date object. But when I display the date, it shows a plus 10 hours time. Lets say I have a date in Java which is

Sat Aug 20 14:00:00 ACT 2011

and the date.getTime() gives 1313866800000. When I pass this timestamp to javascript date object like below.

date=new Date(1313866800000); alert(date);

it alerts a plus 10 hours date as

Sun Aug 21 2011 00:00:00 GMT+0500 (Pakistan Standard Time)

Any ideas on what I may be doing wrong or should I post it to java forums.

Thanks in advance.

[Eric Pascarello]

new Date(milliseconds)

Integer value representing the number of milliseconds since 1 January 1970 00:00:00 UTC (Unix Epoch).

Date MDN Docs

Date.toString() <-- what alert does
Returns the date in a readable string format based on the user's date/time settings.

Eric

[Fawad Ali]

Hi All,
There are two parts to the solution of this problem, but first let me rephrase my problem.

I have certain data against logDate and hour in a data base table. The data looks like below

logDate hr data
2011-09-04 00 12
2011-09-04 01 313
2011-09-04 02 713 .... and so on

I use to get the date from database by rs.getDate and assign it to the java Date object (Here is the first problem, java adds a the server systems timezone offset to it). Then I use the date.getTime() of java to get the time in milli seconds(Remember: this stamp contains the server offset). I paas the stam through json to the javascript and create a javascrip date object by

var date= new Date(timeStamp);
Here is the second problem, javascript adds the client's timezone offset to it.

The solution to this problem would be to get the date from database, convert it to UTC date and show it as UTC date in the front end.
JAVA SOLUTION:

int hour = rs.getInt("HR");
				Calendar cal = Calendar.getInstance();
				cal.setTime(rs.getDate("LogDate"));
				cal.add(Calendar.HOUR_OF_DAY, hour);
				cal.set(Calendar.DST_OFFSET, 0);//set the day light saving to zero
				cal.set(Calendar.ZONE_OFFSET, 0);// set the timezone offset to zero
Long stamp = cal.getTimeInMillis();

JAVASCRIPT SOLUTION:
var date=new Date(val); alert(date.getUTCHours());// Instead of working with date.getHours(), work with date.getUTCHours() etc

I hope it helps someone else. If I am mistaken in something, please let me know.

[Bear Bibeault]

The Java date is likely in UTC. The difference is likely a time zone issue.