I had a similar problem, which I posted last week. You should find it searching the Subject field for "pluggable protocols in web apps" if you kee pold messages. What I found out so far is this: - Defining the protocol handler doesn't do any harm. The URL class searches through the system property "java.protocol.handler.pkgs" if it doesn't get a protocol handler from the factory. - The problem is that URL tries to load the class with Class.forName(String) method (Check out the method static URLStreamHandler getURLStreamHandler(String protocol)). - Class.forName(String) calls the method ClassLoader.getCallerClassLoader(), which returns null. I think this means it uses the remodial classloader - The premodial classloader cannot find the class becaus it is not in the bootstrap classpath. - Subsequently the system class loader is asked to load the class. This classloader cannot find the class either, because the classes in the web application are not in the classpath when tomcat was started. - To solve the problem temporarily is put the protocol handler in the class path. - The disadvantage with this method is you need to distribute the protocol handler separately. And if you need classes from the web application, you need to add the webapp class repository the protocol handler's list of repositories.
Martin Goldhahn > -----Original Message----- > From: Peter Crowther [mailto:[EMAIL PROTECTED] > Sent: Friday, February 11, 2005 2:59 PM > To: Tomcat Users List > Subject: URL protocol handler issues > > Environment: Tomcat 5.0.28, built from source. > > I'm trying to persuade Tomcat to allow me to use a custom URL > scheme ('bod3vfs'), both in webapps and in some of the > behind-the-scenes setup > - for example, I have a custom HostConfig that examines a > virtual file system. I've tried the following approaches to > getting this integrated; none of them appear to work. Ideas welcome! > > 1) Create the handler in org.bodington.core.protocol.bod3vfs.Handler. > Package that into bodington3.jar; place in server/lib. Call > a static routine just after startup to amend > java.protocol.handler.pkgs to include > org.bodington.core.protocol. Result: MalformedURLException > when asking for bod3vfs:*. > > 2) As per 1, but add > -Djava.protocol.handler.pkgs=org.bodington.core.protocol. > Result as 1. > > 3) Amend DirContextURLStreamHandlerFactory to include the following: > > public URLStreamHandler createURLStreamHandler(String protocol) { > if (protocol.equals("jndi")) { > return new DirContextURLStreamHandler(); > } else if (protocol.equals("bod3vfs")) { > return new org.bodington.core.protocol.bod3vfs.Handler(); > } else { > return null; > } > } > > ... and ensure that the factory replaces the standard factory > before it's required, in my custom HostConfig (which is > successfully loaded from bodington3.jar). Result: > java.lang.reflect.InvocationTargetException caused by > java.lang.NoClassDefFoundError: > org/bodington/core/protocol/bod3vfs/Handler at the point that > the runtime attempts to load > DirContextURLStreamHandlerFactory. Note that the compilation > was successful, and that the invoking class has been loaded > successfully from the same jar that contains the handler. If > I replace the return statement with 'return null', > DirContextURLStreamHandlerFactory loads and runs successfully. > > 4) Copy the Handler class into catalina.jar and repeat 3. > Same result. > > Remy, the original code for DirContextURLStreamHandlerFactory > is yours, I think. Any particular reason you replaced the > factory rather than setting the packages? > > - Peter > > -- > Peter Crowther, Director, Melandra Limited John Dalton House, > 121 Deansgate, Manchester M3 2AB > t: +44 (0)161 828 8736 f: +44 (0)161 832 5683 > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
