problem: j2ee, web.xml, about set 2 servlet mapping to the same url

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sods - 07 Jan 2006 11:48 GMT

Hi, all,

I'm newer for j2ee.

I find in some /WEB-INF/web.xml,
there are 2 different servlets mapping to the same url-pattern.

Doesn't it cause problem?
I don't know which will process and give response, when request come.
Whether the two servlet will share the same request obj, or not?

maybe this is designed for monitor servlet.
but i can't imagine what happen with two response to a request.

-Wisdo

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Chris Smith - 08 Jan 2006 03:02 GMT

> I find in some /WEB-INF/web.xml,
> there are 2 different servlets mapping to the same url-pattern.

This shouldn't happen. Can you give an example? Maybe there's
something else really happening there.

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sods - 09 Jan 2006 05:23 GMT

> > I find in some /WEB-INF/web.xml,
> > there are 2 different servlets mapping to the same url-pattern.
>
> This shouldn't happen. Can you give an example? Maybe there's
> something else really happening there.

of course.

example:


<servlet>
<servlet-name>action</servlet-name>

<servlet-class>com.xxxx.webapp.common.struts.XXServlet</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<init-param>
<param-name>validating</param-name>
<param-value>@xx.struts.validate.dtd@</param-value>
</init-param>
<init-param>
<param-name>xx.config.root</param-name>
<param-value>@xx.config.root@</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet>
<servlet-name>action_tmp</servlet-name>

<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<init-param>
<param-name>debug</param-name>
<param-value>3</param-value>
</init-param>
<init-param>
<param-name>detail</param-name>
<param-value>3</param-value>
</init-param>
<load-on-startup>0</load-on-startup>
</servlet>


<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>action_tmp</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>

any ideas?

-sods

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Chris Smith - 09 Jan 2006 06:57 GMT

> 
> <servlet-mapping>
[quoted text clipped - 5 lines]
> <url-pattern>*.do</url-pattern>
> </servlet-mapping>

This is incorrect. I don't see anything in the servlet specification
that specifically defines how a servlet container will deal with this
situation, but there are several statements that imply that it should
choose the first mapping and ignore the second one. However, since that
isn't stated clearly, if such a behavior were observed for some specific
implementation, it would be better to remove the second unused mapping
element to avoid confusion and potential for the web application to
break on future versions of the servlet container.

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The Easiest Way To Train Anyone... Anywhere.

Chris Smith - Lead Software Developer/Technical Trainer
MindIQ Corporation

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josh.s17@gmail.com - 08 Jan 2006 08:40 GMT

Can you paste the relevant section of the web.xml file into your post
so we know exactly what you mean.

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sods - 09 Jan 2006 09:31 GMT

> Can you paste the relevant section of the web.xml file into your post
> so we know exactly what you mean.

the problem is just
there are two servlets.

servlet1:
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>com.xxxx.webapp.common.struts.XXServlet</servlet-class>
</servlet>

servlet2:
<servlet>
<servlet-name>action_tmp</servlet-name>

<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
</servlet>

but they mapping to the same url-pattern, like follow.
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>action_tmp</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>

when a request /$(CONTEXTPAT)/login.do come, I don't know what happen.

Chris think it's incorrect according to the J2EE Specification, and
dangerous to common usage.

-sods

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problem: j2ee, web.xml, about set 2 servlet mapping to the same url

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