in GWT devmode a simple web.xml file not is mapping a URL to a .jsp, even though when in welcome-file-list the .jsp is found
dsw
I am using GWT 2.4 to write an app and I am getting some very strange behavior with my web.xml file. I am trying to isolate exactly what is wrong by building the entire project from scratch as simply as possible and seeing if I can reproduce the behavior. So far I have found the following strange but simple example where web.xml just does not seem to work as expected. You can reproduce it as follows.
Generate the basic app using webAppCreator
gwt-2.4.0/webAppCreator -out waga2 -junit $HOME/junit-4.10/junit-4.10.jar com.waga2.Waga2
Rename war/Waga2.html to war/Waga2.jsp. I also put the following at the top and bottom so I can see the .jsp run:
<%@ page import="java.util.logging.Logger" %>
<%
Logger log = Logger.getLogger("Waga2.jsp");
log.info("\n\n****Waga2.jsp top");
%>
...
<%
log.info("****Waga2.jsp bottom");
%>
When I run this in GWT ant devmode this seems to work as expected: the log messages print to the console and I see the sample GWT client app. Now change the web.xml file as follows:
diff -r 118335a447ba war/WEB-INF/web.xml
--- a/war/WEB-INF/web.xml Mon Apr 16 17:35:38 2012 -0700
+++ b/war/WEB-INF/web.xml Mon Apr 16 18:34:30 2012 -0700
@@ -15,10 +15,14 @@
<servlet-name>greetServlet</servlet-name>
<url-pattern>/waga2/greet</url-pattern>
</servlet-mapping>
-
- <!-- Default page to serve -->
- <welcome-file-list>
- <welcome-file>Waga2.jsp</welcome-file>
- </welcome-file-list>
+
+ <servlet>
+ <servlet-name>Waga2jsp</servlet-name>
+ <jsp-file>Waga2.jsp</jsp-file>
+ </servlet>
+ <servlet-mapping>
+ <servlet-name>Waga2jsp</servlet-name>
+ <url-pattern>/Waga2</url-pattern>
+ </servlet-mapping>
</web-app>
And modify the build.xml so that GWT devmode will visit the new URL:
diff -r 118335a447ba build.xml
--- a/build.xml Mon Apr 16 17:35:38 2012 -0700
+++ b/build.xml Mon Apr 16 18:34:30 2012 -0700
@@ -62,7 +62,7 @@
</classpath>
<jvmarg value="-Xmx256M"/>
<arg value="-startupUrl"/>
- <arg value="Waga2.jsp"/>
+ <arg value="/Waga2"/>
<arg line="-war"/>
<arg value="war"/>
<!-- Additional arguments like -style PRETTY or -logLevel DEBUG -->
Now I just get a 404 when I try to visit the page.
HTTP ERROR: 404
Waga2.jsp
RequestURI=/Waga2
Powered by Jetty://
I pasted in the whole output because it does seem that the server will find that /Waga2 maps to Waga2.jsp, but then it can't find Waga2.jsp, even though it's there.
waga2$ find . | grep Waga2.jsp
./war/Waga2.jsp
Somehow Waga2.jsp is found from the welcome file list, but not from a servlet mapping? What am I missing here?
Daniel Wilkerson
http://stackoverflow.com/questions/10184020/in-gwt-devmode-a-simple-web-xml-file-not-is-mapping-a-url-to-a-jsp-even-though
While bug resulted from me not understanding that a servlet container
is basically a chroot bubble (and therefore redefining the notion of
an absolute path), somehow I think it would be more helpful to
document this a bit more explicitly and for webAppCreator to generate
the servlet mapping I show having an absolute path rather than a
welcome-file-list having a relative path. I'm calling this a bug in
webAppCreator: a wizard should generate code that generalizes in a
straightforward manner.
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