JBoss Seam: components injected into POJOs, but not Session Beans

问题

I have a Seam component that handles login, with the name "authenticator":

@Name("authenticator")
public class AuthenticatorAction implements Authenticator
{
    @PersistenceContext 
    private EntityManager em;

    @In(required=false)   
    @Out(required=false, scope = SESSION)
    private User user;

    public boolean authenticate(){ ... }

}

This works just fine, Seam injects the EntityManager instance. However, as soon as I add the @Stateless annotation, none of the injection happens! In this case, the EntityManager instance is null upon entry to the authenticate() method. Another interesting note is that with a separate stateful session bean I have, the Logger instance in that class is only injected if I make it static. If i have it non-static, it is not injected. Thats fine for the logger, but for stateless session beans like that, I obviously can't have static member variables for these components.

I'm confused because this authenticator is exactly how it is in the Seam booking example: a stateless session bean with a private member variable being injected.

Any ideas?

回答1:

I am curious:

However, as soon as I add the @Stateless annotation, none of the injection happens!

So i hope your Authenticator interface is marked with @javax.ejb.Local or @javax.ejb.Remote. If not, so your Stateless will not work as expected.

When you have a @Stateless Session bean, you must activate a Seam interceptor in order to enable @In-jection. Something like

pureCharger-jar.jar 
    META-INF
        ejb-jar.xml
        persistence.xml

ejb-jar.xml is shown as follows

<?xml version="1.0" encoding="UTF-8"?>
<ejb-jar xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/ejb-jar_3_0.xsd" version="3.0">
    <interceptors>
        <interceptor>
            <interceptor-class>org.jboss.seam.ejb.SeamInterceptor</interceptor-class>
        </interceptor>
    </interceptors>
    <assembly-descriptor>
        <interceptor-binding>
            <ejb-name>*</ejb-name>
            <interceptor-class>org.jboss.seam.ejb.SeamInterceptor</interceptor-class>
        </interceptor-binding>
    </assembly-descriptor>
</ejb-jar>

If possible, take a look at Seam Security with Dan Allen, at JavaOne, author of Seam in Action book.

regards,

来源：https://stackoverflow.com/questions/2404299/jboss-seam-components-injected-into-pojos-but-not-session-beans

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