DONNIE HALE wrote:
> To those interested:
>
> I followed the rabbit trail implied by Craig's response, and have discovered that in
>fact there is an issue when Struts attempts to register its local DTD in the
>initDigester method. However, I believe it may be due to a bug in the Struts code,
>not Enhydra's class loader. The class loader implicitly used by the code in
>ActionServlet.initDigester:
>
> URL url = this.getClass().getResource(registrations[i+1]);
>
> is "org.apache.tomcat.core.ServletClassLoader". I didn't pursue this angle terribly
>far other than to intuit that it wasn't the class loader I expected.
>
> Making a short story long, I figured that the "getResource" method on the servlet
>context was the appropriate method to use, I changed the relevant section in
>initDigester to:
>
> // Register our local copy of the DTDs that we can find
> for (int i = 0; i < registrations.length; i += 2) {
> URL url;
> try {
> url =
>getServletConfig().getServletContext().getResource(registrations[i+1]);
> }
> catch (java.net.MalformedURLException e) {
> url = null;
> }
> if (url != null)
> digester.register(registrations[i], url.toString());
> }
>
> This seems to fix the problem, though I can't say for sure what ill side effects it
>could have. My guess is that one can't assume that the class loader of the servlet
>class itself (at least, perhaps, while it's "init" method is still running) is the
>same as that of the web application as a whole. Consequently, the standard servlet
>getResource method is appropriate because the classpath of the class loader being
>used behind the scenes of that method is the one to which the WEB-INF/lib stuff and
>WEB-INF/classes directories have been added.
>
Unfortunately, this solution is not going to help unless you much -- at least in a
servlet container that conforms to the spec requirements.
ServletContext.getResource() returns you a URL of a web application resource -- in
other words, of a "file" or "directory" entry from the original WAR file. For
example, you can get a URL to read the web.xml file itself, if you want to, by calling:
URL url =
getServletContext().getResource("/WEB-INF/web.xml");
However, the internal copy of the DTD we are talking about here is in the struts.jar
file (along with all the LocalStrings.properties files containing messages generated
by the Struts components themselves). Struts expects to be able to access these
resources via the class loader that the class was loaded from.
URL url =
this.getClass().getResource("/org/apache/struts/resources/struts-config_1_0.dtd");
Among other things, that means the call will succeeed whether you leave the Struts
classes packaged in "struts.jar", or unpack them into WEB-INF/classes -- it is totally
up to the class loader to figure out how to return a URL that can be used to read
these resources. And the class loader in question is the class loader provided by
your servlet container.
Craig McClanahan
>
> Thanks,
>
> Donnie
>
> >>> [EMAIL PROTECTED] 02/12/01 03:01PM >>>
> Lee Hall wrote:
>
> > We've been using the Tomcat 3.2 that is integrated with NetBeans to do
> > our Struts development. Our test deployment server (AIX 4.3 with the
> > IBM 1.2.2 JVM) is running a vanilla Tomcat3.2.1. Neither of these
> > environments has any problem with the subject of this message. Our
> > pre-production server (AIX 4.3 with the IBM 1.2.2 JVM) is running
> > Enhydra 3.1 and fails initialization due to the validation done by
> > ActionServlet. We've tried forcing Xerces 1.2 in Enhydra, but Enhydra
> > persists in it's attempt to validate using the network URL instead of
> > the local resource. I hacked ActionServlet.initDigester() to turn off
> > validation and that got us by - but I know it's the wrong way to deal
> > with this. In spite of the Barracuda project, I would hope that the
> > Enhydra team would want to be completely Tomcat-compatible (which I
> > think includes Struts compatibility). Still, it was easier to "fix"
> > the ActionServlet than to fingure out why we are having this problem
> > with Enhydra. I know, I know... I should have extended ActionServlet
> > to override instead of butchering my clean Struts - but the question
> > remains regarding why this seeming incompatibility exists. Could
> > somebody give me a clue?- Lee
>
> As you can see from the source code in ActionServlet, Struts attempts to
> register its local copy of the DTD in the initDigester() method. It
> uses Class.getResource() to actually acquire a URL for reading the
> contents of the DTD, which is stored as a resource in the "struts.jar"
> file. If the web application class loader in Enhydra has problems
> implementing this method correctly, you could encounter the symptom that
> you report (trying to go across t
