Adding external resources to class-path in Tomcat 8

Question

I have a Tomcat application which needs to reference some properties files that are external to the app. Generally these are stored on a local machine at a specific place like C:\PROJECT_NAME\conf\.

In Tomcat 7 this was achievable by placing a context.xml file inside of /META-INF/ which used a VirtualWebappLoader to essentially add this location to the application classpath as follows:

<Context>
    <Loader className="org.apache.catalina.loader.VirtualWebappLoader"
        virtualClasspath="/PROJECT_NAME/conf"
        searchVirtualFirst="true" />
</Context>

How do I achieve this same thing in Tomcat 8?

Answer 1

There is a section about this in the Tomcat 8 migration guide which will direct you to use a resources configuration

In particular, you will be creating a WebResourceRoot object which contains the following text in its description.

VirtualWebappLoader - Replaced by Pre- and Post-Resources mapped to WEB-INF/lib and WEB-INF/classes

Your new context.xml will look something like the following:

<Context>
    <Resources className="org.apache.catalina.webresources.StandardRoot">
        <PreResources className="org.apache.catalina.webresources.DirResourceSet"
            base="C:\\PROJECT_NAME\\conf"
            internalPath="/"
            webAppMount="/WEB-INF/classes" />
    </Resources>
</Context>