Hi Geeta,
Thank you for the response. Referring from the previous reply on this
topic, it is not recommended to store the connection in a session, since
connection object will have to be created each time a user makes a request
to our servlet. That's why I am trying to put in servletcontext object.
I also have tried to put the connection in request object:
request.setAttribute("connection", myConnection); // in first servlet
then in the second servlet just call request.getAttribute("connection");
Can anybody explain to me if there is any drawback doing it this way and
not in servletcontext? is servletcontext the appropriate place to store
connection object from connectionPool?
Thank you.
Andi Setiyadi
Geeta Ramani
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Hi Andi;
Since code in the init() method is executed *exactly* once at servlet
initialization time (*not*
once per request), you wouldn't want to have:
context.setAttribute("connection", connection");
in the init method at all. (Because i don't imagine you want to share the
connection object amongst
all users.)
Instead you want to initialize the ConnectionPool in the init method (since
that needs to be done
be only once), and in the doPost/doGet (of the first servlet) you may want
to have code like this:
HttpSession session = req.getSession(true);
Connection connection = myConnectionPool.getconnection();
session.setAttribute("connection", connection);
Then in your second servlet you should be able to access that connection
object via:
HttpSession session = req.getSession(false); //dont create a session if one
doesn't exist
if (session == null){
//code for redirecting to first sevlet..
}
else {
Connection connection = session.getAttribute("connection");
//etc.
}
Andi Setiyadi wrote:
> I try to use connection pooling to make database connection and put the
> connection object in ServletContext. Here is how my application work.
> - user login through JSP and submit the request which handled by first
> level servlet. In the init( ), I did:
> ServletContext context = getServletContext( ), then make database
> connection and put in the attribute
> context.setAttribute("connection", connection");
>
> - first level servlet then call second level servlet. In the second
> servlet I try to getServletContext( ):
> ServletContext context = getServletContext( );
>
> When executing that line, I got the following error:
>
> null
> java.lang.NullPointerException
> at
> javax.servlet.GenericServlet.getServletContext(GenericServlet.java:205)
> at
com.wg.hr.PersonnetWelcome.execute(PersonnetWelcome.java:37)
> at com.wg.hr.Personnet.doGet(Personnet.java:67)
> at com.wg.hr.Personnet.doPost(Personnet.java:85)
> ...
>
> Any suggestion is appreciated
> Thanks,
> Andi
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