Re: help in jdbc/jndi/java class

From:
Juha Laiho <Juha.Laiho@iki.fi>
Newsgroups:
comp.lang.java.help
Date:
Thu, 25 May 2006 12:33:32 +0000 (UTC)
Message-ID:
<e5486s$sko$2@ichaos2.ichaos-int>
Juha Laiho <Juha.Laiho@iki.fi> said:

"Manoj Jain" <Manoj.S.J@gmail.com> said:

i've created some simple java beans, when i do log in, i forward it to
servlet where i create LoginDTO object from username and password. in
the same class i validate the username and password with the system.
but it returns null value to connection object.

....

public static void connect()
   {
       try
       {
               ic= new InitialContext();
               DataSource ds=(DataSource)ic.lookup("jdbc/proformaInvoice");
               conn=ds.getConnection();
               System.out.println("Hello World"); //to check whether it comes to this line or not.
       }
       catch(SQLException se){}
       catch(NamingException ne){}
   }


Well, in the above you're explicitly throwing away any exception
information you may be getting. At least print out the exception stacks
in the catch {} blocks.


[don't you hate it when you realize just after posting a message that there's
still a bit more to say..]

So, adding to the previous response; if the exception data doesn't provide
any additional help, then write a simple, plain servlet which does a very
simple database transaction:

- fetch JNDI initial context
- fetch data source through the context
- get connection from the data source
- make db query through the connection
- close connection

.... and have the servlet print out (to the browser) the results of each
and every operation - and also details of each and every exception. Once
you get this working, you can start to change it towards your desired
abstraction model.
--
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