Hi Abhay
I figured how to save the sessions at least one half the equation but
the other half will not be portable.BTW Looking at J2EE Doc `HttpSessionContext'
is a deprecated class, but I need something for JServ 1.1.2 at least.
This method actual gets all the session object in JServ (JServSession) and
adds them to hashtable. It then serialises the hashtable to a file.
public void writeSessionInfo( Parameters params )
throws IOException
{
HttpServletRequest req = params.req;
HttpServletResponse res = params.res;
PrintWriter out = params.out;
HttpSession session = params.session;
HttpSessionContext cxt = session.getSessionContext();
out.println("session context class = "+cxt.getClass().getName()+"<br>" );
out.println("session context hashcode = "+cxt.hashCode()+"<br>" );
out.println("<center>");
out.println("<table width=\"95%\" border=\"1\" cellpadding=\"3\"
cellspacing=\"0\" >" );
// Container for persistant sessions
Hashtable session_list = new Hashtable();
int index=0;
Enumeration etor = cxt.getIds();
while ( etor.hasMoreElements() ) {
Object key = etor.nextElement();
HttpSession ses = cxt.getSession( key.toString() );
session_list.put( key, ses );
out.println("<tr><td width=\"20%\" >"+index+"</td><td>"+
key.getClass().getName()+"</td>"+
"<td>"+key+"</td><td>"+ses.hashCode()+"</td></tr>" );
++index;
}
out.println("</table>");
out.println("</center>");
out.println("<br><br>");
FileOutputStream fos=null;
ObjectOutputStream oos=null;
try {
out.println("Writing session file." );
fos = new FileOutputStream( SESSION_FILE );
oos = new ObjectOutputStream( fos );
oos.writeObject( session_list );
oos.flush();
out.println("<font color=\"#008000\" ><b>Complete</b></font>");
}
catch ( IOException ioe ) {
out.println("<font color=\"#FF0000\" ><b>Failure</b></font>");
throw ioe;
}
finally {
if ( oos != null ) {
try { oos.close(); } catch (IOException ignored ) {}
}
if ( fos != null ) {
try { fos.close(); } catch (IOException ignored ) {}
}
}
}
Looking in the JServ source code. There is a method `JServManager.createSession'
that create session with HttpServletResponse object which actually happens
to be `JServConnector' object. So I think part II is possible.
Write initialistaion servlet
1. init( ServletConfig) fires a thread X and sets the flag F = false
2. This thread X sleeps for a nap (500ms) and then invokes a URL request to the servlet
This thread is basically acting as HTTP client reading the contents of URL
sinking it.
3. the servlet will be called in `doGet'
4. In `doGet' if the flag F is true then do nothing. Else set the F to true
recreate the sessions from the persistant saved file.
5. The sessions should be restored.
Does anyone disagree or agree with this for JServ 1.1.2 at least?
--
Peter Pilgrim
G.O.A.T
"The Greatest of All Time"
---------------------------------------- Message History
----------------------------------------
From: [EMAIL PROTECTED] on 06/11/2000 11:34
Please respond to [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
cc:
Subject: Re: Shared Servlet Engine and Sessions [Scanned by Yellow Pages
PostMaster]
Hi !
I have not used JSERV till now, but JRUN gives such a facility. It has
an option to use a jrun servlet engine as session persistant engine. It
stores sessions in a flat file at the time of shutting down and recovers
them on restart.
Abhay
> Peter Pilgrim <[EMAIL PROTECTED]> on 11/06/2000 10:21:00 AM
>
> To: [EMAIL PROTECTED]
> cc: (bcc: Charles Chen/YellowPages)
> From: Peter Pilgrim <[EMAIL PROTECTED]>, 6 November 2000, 10:21
a.m.
>
> Shared Servlet Engine and Sessions [Scanned by Yellow Pages PostMaster]
>
>
> I have a question about shared servlets web hosting.
>
> My web hoster provides a single Java servlet engine (Apache jserv)
> which shared across many Apache virtual host. Because of people
> writing bad servlets, the web hoster has adopted the policty of
shutdowning
> and restarting the servlet engine every 15 minutes.
>
> The consequence is that all sessions are gone.
>
> 1) Can one detect when the servlet engine starts or shutdown?
> (Probably look in the JServ open source )
>
> 2) Can one recreate sessions at start up?
> (Probably look in the JServ open source )
>
> 3) Is there a way to save the sessions to a database or persistant file
store?
>
> 4) Has anyone done this for Jserv or any another engine?
>
--<CUT>--
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