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From "Luba Powell" <luba...@bellatlantic.net>
Subject Re: How can I make tomcat to instantiate a class
Date Thu, 14 Jun 2001 22:03:07 GMT
This awfully good...
----- Original Message -----
From: "Bo Xu" <bo@cybershop.ca>
To: <tomcat-user@jakarta.apache.org>
Sent: Thursday, June 14, 2001 5:15 PM
Subject: Re: How can I make tomcat to instantiate a class


> > ...But actually my problem was to instantiate a class when
> > tomcat boots up...so that i can use that object across sessions.Can u
> > suggest something towarsd this.
> > [...]
>
> Hi :-)  I find the following is from servlet-2_3-pfd2-spec.pdf(for
> Servlet containers which supports Servlet spec2.3):
>
> *
> ...
> SRV.10.2.2 An Example of Listener Use
> To illustrate a use of the event scheme, consider a simple web application
> containing a number of servlets that make use of a database. The developer
> has provided a serv-let context listener class for management of the
database
> connection.
> 1. When the application starts up, the listener class is notified. The
> application logs on to the database, and stores the connection in the
> servlet context.
>
> 2. Servlets in the application access the connection as needed during
> activity in the web application.
>
> 3. When the web server is shut down, or the application is removed from
> the web server, the listener class is notified and the database connection
is
> closed.
> ...
>
>
> * and I think perhaps there is another way:
>    - make a "startupServlet", and in its "servlet-declaration" in
>      WEB-INF/web.xml, set the following:
>       <load-on-startup>1</load-on-startup>
>       now/so when TC is started, the "init" method of this
"startupServlet"
>       will be invoked by container
>    - in the "init" method in this "startupServlet", a SingleTon pattern
>      "startupUtility" is instantiated: for example, by invoking a public
static
>      "Factory method":
>       public void init(ServletConfig config) throws ServletException{
>           super.init(config);
>           ...
>           startupUtility.makeInstance();
>           ...
>       }
>
>    - now after a while(instantiating time),  a instance of  startupUtility
is
> available
>      (for example, a DBConnectionpool)
>
>
> Bo
> June 14, 2001
>
>
>


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