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Date Parsing Issue...

Somnath Mallick
Ranch Hand

Joined: Mar 04, 2009
Posts: 477
Hi Everyone,

I have a date which of the format "15-Dec-2009 06:13:14" enetered by the user as String. I want to convert it to Date format (java.util.Date). But i am getting the error as unable to parse in my code.



Error Stack:

Christophe Verré
Sheriff

Joined: Nov 24, 2005
Posts: 14688
    
  16

The first thing striking my eyes is that you're using MM for both months and minutes You need to read carefully the java.text.SimpleDateFormat API.


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Jesper de Jong
Java Cowboy
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Joined: Aug 16, 2005
Posts: 14268
    
  21

The codes you use to specify the date format when you create a SimpleDateFormat object are case-sensitive. So "DD-MM-YYYY HH:MM:SS" doesn't mean what you think it means. Lookup the documentation for SimpleDateFormat for information on how to specify the format.

Also, the "MM" you use for the months is not going to match three-letter month abbreviations like "Dec".


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Somnath Mallick
Ranch Hand

Joined: Mar 04, 2009
Posts: 477
I modified the code after going through the API.



Now I get the error as:

Also i checked the API and found that 14-Dec-2009 17:00:00 type of date is not mentioned anywhere!
Somnath Mallick
Ranch Hand

Joined: Mar 04, 2009
Posts: 477
Got it after a little further reading and experiments. This worked for me! Thanks!

Jesper de Jong
Java Cowboy
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Joined: Aug 16, 2005
Posts: 14268
    
  21

Somnath Mallick wrote:Got it after a little further reading and experiments. This worked for me! Thanks!


Are you sure that this works correctly? Note that MM (upper-case) is the month number, not minutes, and SS (upper-case) is milliseconds, not seconds.
Somnath Mallick
Ranch Hand

Joined: Mar 04, 2009
Posts: 477
^^Well at least, Well do you mean to say that i should change it like this?


Also one more question, Lets for example take the code:


time is in GMT.
InputBean.getSearchStartTimeStamp() and InputBean.getSearchEndTimeStamp() are in IST.
Will they yield a proper result? I mean does JVM does the IST to GMT conversions internally?
Ulf Dittmer
Marshal

Joined: Mar 22, 2005
Posts: 42276
    
  64
I mean does JVM does the IST to GMT conversions internally?

No. The Date class has no notion of timezones; you'll need to use the Calendar class instead.


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Somnath Mallick
Ranch Hand

Joined: Mar 04, 2009
Posts: 477
I modified the code to this:

But still all the dates are printing in IST!
Ulf Dittmer
Marshal

Joined: Mar 22, 2005
Posts: 42276
    
  64
As I said before, the Date class has no concept of timezones, therefore Date.toString is not likely to do the right thing. Use DateFormat.format instead, and make sure to set its timezone (which the code currently is not doing).
Jesper de Jong
Java Cowboy
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Joined: Aug 16, 2005
Posts: 14268
    
  21

Somnath Mallick wrote:^^Well at least, Well do you mean to say that i should change it like this?

Yes, but note that hh (lower-case) for the hours means the hour in AM/PM (1-12) - this will fail if hours is 17. Try this:


Somnath Mallick wrote:But still all the dates are printing in IST!

Yes, because Date.toString() uses the local timezone setting of your system - it displays the Date object in your local timezone. Instead of using Date.toString(), format the date object using a DateFormat object; set the timezone that you want your date displayed in on the DateFormat object. As Ulf said, class Date itself doesn't know about timezones.
Somnath Mallick
Ranch Hand

Joined: Mar 04, 2009
Posts: 477

I hope this is correct? But when the time is printing no time zone is getting printed so i cant really say the times are really in GMT or IST.
Also when i am trying to insert this value in an excel sheet using POI API, i had to convert all time values to string, so all the data entered in the Excel sheet is IST!
 
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