Inject EJB into Servlet

Question

Does anyone know why it's so difficult to inject an EJB into a Servlet? I'm using JBoss 6.2. My handler variable is null no matter what I try.

@Local
public interface RequestHandlerInterface {
    public String handleRequest(String authKey);    
}

@Singleton
public class RequestHandler implements RequestHandlerInterface {
...
}

public class Test extends HttpServlet {
    @EJB
    private RequestHandlerInterface handler;  //Always null
}

In application context:

<bean id="requestHandler" class="company.application.RequestHandler" />

In web.xml (v3.0):

<servlet>
    <servlet-name>Test</servlet-name>
    <servlet-class>company.test.Test</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>Test</servlet-name>
    <url-pattern>/Test</url-pattern>
</servlet-mapping>

  <ejb-local-ref>
    <ejb-ref-name>RequestHandler</ejb-ref-name>
    <ejb-ref-type>Session</ejb-ref-type>
    <local>company.application.RequestHandlerInterface</local>
  </ejb-local-ref>

I've tried so many combinations, with every @EJB(...) option... any idea?
Note: It is all contained in a single WAR.
Note: I've tried private RequestHandler handler; instead of the interface.
Note: I've tried with (name="ejb/RequestHandler") and mappedName, beanName, lookup
Note: I've tried with @Remote and @Local, with ejb-local-ref and ejb-ref

Note:
JNDI bindings for session bean named RequestHandler in deployment unit deployment "company.war" are as follows:

java:global/company/RequestHandler!company.application.RequestHandlerInterface
java:app/company/RequestHandler!company.application.RequestHandlerInterface
java:module/RequestHandler!company.application.RequestHandlerInterface
java:global/company/RequestHandler
java:app/company/RequestHandler
java:module/RequestHandler

Possible duplicate of [How to connect HttpServlet with Spring Application Context in web.xml?](https://stackoverflow.com/questions/1866953/how-to-connect-httpservlet-with-spring-application-context-in-web-xml) — Dave Jarvis, Jun 01 '17 at 20:00

score 1 · Answer 1 · answered Mar 19 '14 at 09:42

1

Use local instead of home as below

<ejb-ref>
   <ejb-ref-name>ejb/RequestHandler</ejb-ref-name>
   <ejb-ref-type>Session</ejb-ref-type>
   <local>company.application.RequestHandlerInterface</local>
</ejb-ref>

answered Mar 19 '14 at 09:42

Jay

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(Note, I got rid of "ejb/" to simplify my example) – djb Mar 19 '14 at 09:54
Try to remove all the contents and check again. – Jay Mar 19 '14 at 11:53
No change. "Injected" RequestHandler still null. – djb Mar 20 '14 at 13:46
It worked perfectly fine for me on JBoss EAP 6.1, but I tried on Stateless instead of Singleton EJB. I didn't even defined any – Jay Mar 20 '14 at 14:20
Hmm, it may be a scope issue, since Servlets are session scoped, and singletons are application scoped. I ended up setting up a queue between my Servlet and EJB, which is pretty ridiculous. But it works, at least. I'm going away for a week, but will test when I get back. Thanks for the help. – djb Mar 20 '14 at 14:34

score 0 · Accepted Answer · edited May 23 '17 at 12:20

0

I found the answer here: How to connect HttpServlet with Spring Application Context in web.xml?

Maybe Jay's answer works for EJB-only configurations. But my app is Spring configured, so I'm guessing it must be some issue whereby Spring takes control and disallows injection unless it knows about it.

edited May 23 '17 at 12:20

Community

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answered Aug 13 '14 at 14:08

djb

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Well if you're using Spring you probably should be using a Spring annotation to do the injection, not the JEE @EJB annotation. – Gimby Aug 13 '14 at 14:36

Inject EJB into Servlet

2 Answers2