thanks for the help,
one further question, if I initialise a Database connection within the init() method
of a servlet and use this reference in the doGet() for example, will each servlet
share this connection object? ie if more than one servlet requests the same connection
would this result in a runtime exception?
ie
public void ExampleServlet extends HttpServlet{
private connection_;
public void init(){
//do something to open and get a database connection
}
public void doGet(HttpServletRequest req_, HttpServletResponse res_){
//now use the connection_ reference here to execute
//a database sql query
//if this reference is shared between multiple
//servlet invocations is it right to assume this would
//be unsafe !
}
}
thanks again in advance!
robbie
-----Original Message-----
From: William Brogden [mailto:[EMAIL PROTECTED]]
Sent: 06 March 2001 14:01
To: [EMAIL PROTECTED]
Subject: Re: threading issues with tomcat
Byrom Robert-LRB005 wrote:
>
> hello all
>
> Im hoping someone can help,
>
> can someone please explain how the threading works when a new servlet is initialised
>within the tomcat container? If multiple requests are recieved for a servlet, is the
>same servlet data area shared amongst each thread that invokes the servlet? and if
>many requests are made for the same servet, how does tomcat deal with the demand?
Only a single servlet object exists in the container but there
can be many Threads executing in the code. Each Thread has
a request object and response object (and possibly a session
object) belonging to a particular request. Each Thread shares
the instance variables of the servlet but local variables in
servlet methods are unique to the Thread.
Thats why you should not use servlet instance variables for
anything unique to a particular request. Data that has to be
associated with a particular user between requests should be
stored in the session.
--
WBB - [EMAIL PROTECTED]
Java Cert mock exams http://www.lanw.com/java/javacert/
Author of Java Developer's Guide to Servlets and JSP
ISBN 0-7821-2809-2
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