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From Steve Weiss <swe...@aamc.org>
Subject Re: Retrieving Objects from the Session Results in a Null Pointer
Date Tue, 15 Aug 2000 19:37:06 GMT
Yes, the implicit object is named 'session'. I don't know that you can
rename it, but if you do:

HttpSession mySession = request.getSession( [true|false] );

You should get the appropriate session back.

-S

Hunter Hillegas wrote:
> 
> I see...
> 
> When using page session=true, is the object implicitly named session? Can I
> change the name of the implicit object?
> 
> Hunter Hillegas, MCP
> Web Engineer / System Administrator - Jacob Stern & Sons, Inc.
> hhillegas@jacobstern.com
> 805-565-1411 PH * 805-565-8684 FAX
> 
>  -----Original Message-----
> From:   Steve Weiss [mailto:sweiss@aamc.org]
> Sent:   Tuesday, August 15, 2000 11:02 AM
> To:     tomcat-user@jakarta.apache.org
> Subject:        Re: Retrieving Objects from the Session Results in a Null
> Pointer
> 
> Using the "page session" directive is not only better, it's required to
> maintain session information between JSPs. When you do
> request.getSession(true/false) inside your JSP, the session object you
> get is only valid for that page, unless you declare that the JSP is
> "playing sessions" with other JSPs. Once you've done that, you *still*
> need to obtain a session object with request.getSession(), and the
> boolean parameter says "create/don't create a new one" if one doesn't
> already exist.
> 
> -S
> 
> Hunter Hillegas wrote:
> >
> > I am sorta new to JSP. I've been doing servlets for quite some time...
> >
> > I understand that there is a facility to automagically use a session on a
> > page without declaring it:
> >
> > <%@ page session="true" %>
> >
> > instead of doing:
> >
> > theSession = request.getSession(Boolean);
> >
> > is declaring in the page a better approach?
> >
> > As far as using the depreciated method, thanks for the heads up. I'll try
> > that...
> >
> > Hunter Hillegas, MCP
> > Web Engineer / System Administrator - Jacob Stern & Sons, Inc.
> > hhillegas@jacobstern.com
> > 805-565-1411 PH * 805-565-8684 FAX
> >
> >  -----Original Message-----
> > From:   Steve Weiss [mailto:sweiss@aamc.org]
> > Sent:   Tuesday, August 15, 2000 9:56 AM
> > To:     tomcat-user@jakarta.apache.org
> > Subject:        Re: Retrieving Objects from the Session Results in a Null
> > Pointer
> >
> > Two suggestions:
> >
> > 1. You do have- <%@ page session="true" %> in your JSPs, yes? If not you
> > won't be able to maintain session information from one page to another.
> > 2. Use session.getAttribute() instead of session.getValue(), which is
> > deprecated.
> >
> > -Steve
> >
> > Hunter Hillegas wrote:
> > >
> > > I have this code:
> > >
> > > <%
> > > theSession = request.getSession(false);
> > >
> > > shoppingCart cart = null;
> > >
> > > try {
> > >     cart = (shoppingCart)theSession.getValue("shoppingCart"); //This is
> > > causing a null pointer exception. Arghhhh...
> > > }
> > > catch (Exception e) {
> > >     e.printStackTrace();
> > > }
> > > %>
> > >
> > > that pulls an object out of the session...
> > >
> > > I can verify that the object is in the session. I can grab it from the
> > page
> > > I inserted it from with this code:
> > >
> > > shoppingCart testCart =
> (shoppingCart)theSession.getValue("shoppingCart");
> > >
> > > I just can't get it from any other pages...
> > >
> > > Any ideas?
> > >
> > > Hunter Hillegas, MCP
> > > Web Engineer / System Administrator - Jacob Stern & Sons, Inc.
> > > hhillegas@jacobstern.com
> > > 805-565-1411 PH * 805-565-8684 FAX
> >
> > --
> > Steve Weiss      Association of American Medical Colleges
> > (202)828-0428    mailto:sweiss@aamc.org    http://www.aamc.org
> 
> --
> Steve Weiss      Association of American Medical Colleges
> (202)828-0428    mailto:sweiss@aamc.org    http://www.aamc.org

-- 
Steve Weiss      Association of American Medical Colleges
(202)828-0428    mailto:sweiss@aamc.org    http://www.aamc.org

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