Configurable values to MDB annotations

问题

I'm trying to use this method for receiving mail in our EJB3 app. In short, that means creating an MDB with the following annotations:

@MessageDriven(activationConfig = { @ActivationConfigProperty(propertyName = "mailServer", propertyValue = "imap.company.com"),
    @ActivationConfigProperty(propertyName = "mailFolder", propertyValue = "INBOX"),
    @ActivationConfigProperty(propertyName = "storeProtocol", propertyValue = "imap"),
    @ActivationConfigProperty(propertyName = "debug", propertyValue = "false"),
    @ActivationConfigProperty(propertyName = "userName", propertyValue = "username"),
    @ActivationConfigProperty(propertyName = "password", propertyValue = "pass") })
@ResourceAdapter("mail-ra.rar")
@Name("mailMessageBean")
public class MailMessageBean implements MailListener {
    public void onMessage(final Message msg) {
       ...snip...
    }
}

I have this working, but the situation is less than ideal: The hostname, username and password are hardcoded. Short of using ant and build.properties to replace those values before compilation, I don't know how to externalize them.

It would be ideal to use an MBean, but I have no idea how to get the values from the MBean to the MDB configuration.

How should I do this?

回答1:

You can externalise the annotations into the ejb-jar.xml that you deploy in the META-INF of your jar file as follows:

<?xml version="1.0" encoding="UTF-8"?>

<ejb-jar version="3.0">
    <enterprise-beans>
        <message-driven>
            <ejb-name>YourMDB</ejb-name>
            <ejb-class>MailMessageBean</ejb-class>        
            <activation-config>
                <activation-config-property>
                   <activation-config-property-name>username</activation-config-property-name>
                   <activation-config-property-value>${mdb.user.name}</activation-config-property-value>
                </activation-config-property>
...
...
            </activation-config>
        </message-driven>
    </enterprise-beans>

Then you can set the mdb.user.name value as a system property as part of the command line to your application server using -Dmdb.user.name=theUserName and it will magically get picked up by the mdb.

Hope that helps.

回答2:

As of JBoss AS 5.1 at least, you can use AOP to configure the @ActivationConfigProperties. I discovered this by looking at the examples that jboss provides here. This is useful if you do not want your username and passwords available to the entire container in a systems property, or if you are like me and never, I repeat NEVER, want to deploy an artifact with a username/password in it. Any how, here is the jist...

Annotate the mdb like this...

...
@MessageDriven
@AspectDomain("TestMDBean")
public class TestMDBean implements MessageListener {
...

Then add a ${whatever}-aop.xml to the deploy dir with internals like below. I left the original comments in there in case Jaikiran does make the changes mentioned...

Note: the annotation must be on one line only.

<?xml version="1.0" encoding="UTF-8"?>
<aop xmlns="urn:jboss:aop-beans:1.0">
   <!-- TODO: Jaikiran - These interceptor declarations need not be here since they 
   are already declared through the ejb3-interceptors-aop.xml. Duplicating them leads to
   deployment errors. However, if this custom-ejb3-interceptors-aop.xml needs to be 
   independent, then we must find a better way of declaring these. Right now, commenting these
   out, can be looked at later. -->
   <!--    
   <interceptor class="org.jboss.ejb3.AllowedOperationsInterceptor" scope="PER_VM"/>
   <interceptor class="org.jboss.ejb3.entity.TransactionScopedEntityManagerInterceptor" scope="PER_VM"/>
   <interceptor factory="org.jboss.ejb3.security.RunAsSecurityInterceptorFactory" scope="PER_CLASS"/>
   <interceptor class="org.jboss.ejb3.stateless.StatelessInstanceInterceptor" scope="PER_VM"/>

   <interceptor factory="org.jboss.ejb3.interceptor.EJB3InterceptorsFactory" scope="PER_CLASS_JOINPOINT"/>
   <interceptor factory="org.jboss.aspects.tx.TxInterceptorFactory" scope="PER_CLASS_JOINPOINT"/>
   -->
   <domain name="TestMDBean" extends="Message Driven Bean" inheritBindings="true">
      <annotation expr="!class(@org.jboss.ejb3.annotation.DefaultActivationSpecs)">
         @org.jboss.ejb3.annotation.DefaultActivationSpecs (value={@javax.ejb.ActivationConfigProperty(propertyName="destinationType", propertyValue="javax.jms.Queue"), @javax.ejb.ActivationConfigProperty(propertyName="destination", propertyValue="queue/MyQueue"), @javax.ejb.ActivationConfigProperty(propertyName="user", propertyValue="testusr"), @javax.ejb.ActivationConfigProperty(propertyName="password", propertyValue="testpwd")})
      </annotation>
   </domain>
</aop>

来源：https://stackoverflow.com/questions/308188/configurable-values-to-mdb-annotations