What else do I need in ejb 2.x ear?

Question

I have now

ear 
|----test.jar
     |-------META-INF
             |-------application.xml
     |-------test
             |-------Test.class
             |-------TestEJB.class
             |-------TestHome.class
|----test.war
     |-------WEB-INF
             |-------web.xml
     |-------test
             |-------TestServlet.class

application.xml

<application>
  <display-name>Ejb Test</display-name>
  <module>
    <ejb>test.jar</ejb>
  </module>
  <module>
    <web>
      <web-uri>test.war</web-uri>
      <context-root>/test</context-root>
    </web>
  </module>
</application>

web.xml

<web-app>
  <servlet>
    <servlet-name>Test</servlet-name>
    <servlet-class>test.TestServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Test</servlet-name>
    <url-pattern>/test</url-pattern>
  </servlet-mapping>
</web-app>

Is there something I'm missing from a working ear application and what's the purpose of these configuration files? How do I access the services of my ejb from the servlet?

Answer 1

You'll need an EJB deployment descriptor in test.jar/META-INF/ejb-jar.xml and the EAR deployment descriptor has to go to your.ear/META-INF/application.xml (NOT inside the EJB jar!).

The ejb-jar.xml will contain something like the following XML fragment for your EJBs:

<enterprise-beans>
    <session>
        <ejb-name>MyCoolEJB</ejb-name>
        <local-home>test.TestHome</local-home>
        <local>test.Test</local>
        <ejb-class>test.TestEJB</ejb-class>
    </session>

    <!-- ... more <session/> or <entity/> entries ... -->
</enterprise-beans>

I worked with EJB3 myself, where things are a little bit different and you don't have the home interfaces any longer. So take my example with a grain of salt.

Inside the web.xml you'll have to have a corresponding reference to the EJB:

<ejb-local-ref>
    <ejb-ref-name>TheJNDINameOfYourEJB</ejb-ref-name>
    <ejb-ref-type>Session</ejb-ref-type>
    <ejb-link>MyCoolEJB</ejb-link>   <!-- the value from <ejb-name/> above -->
</ejb-local-ref>

The <ejb-link/> points to the corresponding <ejb-name/> of your EJB, if your reference is in the same JAR as your EJB. Otherwise, you'll have to preprend the name of the JAR such as <ejb-link>test.jar#MyCoolEJB</ejb-link>.

Then, in your servlet you can do a JNDI lookup for "java:comp/env/TheJNDINameOfYourEJB" to access the home interface of your EJB. I hope, that gave you a few pointers to delve deeper yourself.

BTW: If EJB 2.x is not a fixed requirement, then have a look at EJB 3.x. A lot of things got easier to use in that version!

Answer 2

Your EJB doesn't seem well packaged: it should be in it's own EJB module and I can't see the EJB deployment descriptor (an ejb-jar.xml file). Have a look at Packaging Applications and Directory Structure in an EJB Module JAR File