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From "Tom Bednarz" <l...@bednarz.ch>
Subject Re: server.xml - context parameter question
Date Tue, 30 Apr 2002 09:45:28 GMT
Abe,

Thanks for the input. It is not that easy since I run TOMCAT on W2K as a
system service. There is a batch file which allows settings of environment
variables. However I think it would be better to set application specific
variables in an application context and environment variables for container
configuration only. But thanks for the input anyway.

Tom


----- Original Message -----
From: "Abraham Fathman" <afathman@one.net>
To: "'Tomcat Users List'" <tomcat-user@jakarta.apache.org>
Sent: Tuesday, April 30, 2002 9:31 AM
Subject: RE: server.xml - context parameter question


> Tom,
>
> I haven't done this before but I thought that it might help you out.
>
> Instead of using the server.xml you could try adding your variables as
> system properties. I believe you can do this by creating a setenv.sh/bat
> file in your bin directory. Here you can set an environmental variable
> JAVA_OPTS=-Ddbserer=dbserver.
>
> The catalina scripts should call this setenv script which will set the
> JAVA_OPTS env variable. Then your code should be able to get this
> property from the System.getProperty("dbserver") line.
>
> Just a thought. Hope it helps,
>
> Abe
>
> -----Original Message-----
> From: Tom Bednarz [mailto:list@bednarz.ch]
> Sent: Tuesday, April 30, 2002 3:18 AM
> To: Tomcat User List
> Subject: server.xml - context parameter question
>
>
> Hi
>
> I have a problem in initializing my web application. The application
> stores all of its configuration parameters in a database table. My
> application has an initialization servlet which loads beside other
> things the configuration. Initially this is done in the init method,
> over time it is periodically done in a separate thread.
>
> The problem is, that I need to compose a JDBC connect URL. One of the
> components of this URL is the name or IP address of the database server.
> This information cannot be put in the web.xml of the web application
> since it depends on the runtime environment and cannot be pre-defined at
> development time. To access the configuration information in the
> database I need this JDBC connect URL. So I was looking for a
> possibility to define parameters OUTSIDE my web application.
>
> I found a context tag under the host tag in the server.xml file. The
> TOMCAT documentation says:
>
>  --------  snip ------------------------
> You can configure named values that will be made visible to the web
> application as servlet context initialization parameters by nesting
> <Parameter> elements inside this element. For example, you can create an
> initialization parameter like this:
>
> <Context ...>
>   ...
>   <Parameter name="companyName" value="My Company, Incorporated"
>          override="false"/>
>   ...
> </Context>
>
>
>
> This is equivalent to the inclusion of the following element in the web
> application deployment descriptor (/WEB-INF/web.xml):
>
> <context-param>
>   <param-name>companyName</param-name>
>   <param-value>My Company, Incorporated</param-value> </context-param>
>
>
>
> but does not require modification of the deployment descriptor to
> customize this value.
>
> -------------- end --------------------------
>
> So I did the following:
>
> <Context path="/MyWebapp" docBase="MyWebapp" debug="0"
> privileged="true">
>      <Parameter name="DBServer" value="MyDatabaseServer"
> override="false"/> </Context>
>
> In the init() method of my initialization servlet (preload=1) I did the
> following:
>
>         for (java.util.Enumeration e = config.getInitParameterNames();
> e.hasMoreElements();)
>             mAppLog.debug("\t"+(String)e.nextElement());
>
> where config is the ServletConfig object which is a parameter of the
> HttpServlet.init(..) method. I expected to find the name DBServer as a
> parameter name but it does NOT appear. Only those parameters defined in
> the web applications web.xml file appear!
>
> Could anybody explain me what I am doing wrong? What happens to context
> entries in the server.xml file if the named context is NOT YET installed
> e.g. is in the webapps directory as .war file?
>
> Any help would be greatly appreciated.
>
> Thomas
>
>
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