@Resource injection problem with JNDI

[Sreedevi Vinod]

hi,

I want to do a JNDI lookup of a data source using the @Resource annotation. When I use the string "java:comp/env/demoDS" or "demoDS" it does not work. But if I use the lookup() method of the SessionContext and pass the name "demoDS", it works perfectly. Why doesn't the JNDI lookup work? The code is shown below.

Thanks,
Devi.

@Stateless
@Resource(name="demoDS",mappedName="java:/demoDS")
@RemoteBinding(jndiBinding="ProcessRemote")
public class ProcessPaymentBean implements ProcessPayment{
@Resource SessionContext sc;

public String getProductInfo(int product_id){
Connection conn1 = null;
String product = null;
try{
   // DataSource demoDS = (DataSource)sc.lookup("demoDS");
Context ctx = new InitialContext();
DataSource demoDS = (DataSource)ctx.lookup("demoDS");
        conn1 = demoDS.getConnection();
        PreparedStatement ps = conn1.prepareStatement("select * from product where product_id=?");
        ps.setInt(1,product_id);
        ResultSet rs = ps.executeQuery();
    while(rs.next()){
    product = rs.getString("product_name");
    }
   return product;
}
catch(Exception e){
throw new EJBException(e.getMessage());
}
finally {
try {
if(null != conn1)
conn1.close();
}
catch(SQLException e){
throw new EJBException(e.getMessage());
}
}
}
 
}

[Jaikiran Pai]

@Stateless
@Resource(name="demoDS",mappedName="java:/demoDS")
@RemoteBinding(jndiBinding="ProcessRemote")
public class ProcessPaymentBean implements ProcessPayment

Shouldn't the resource injection be at field level instead of class level? Something like:

@Stateless
@RemoteBinding(jndiBinding="ProcessRemote")
public class ProcessPaymentBean implements ProcessPayment {
  // Inject resources based on jndi names
  @Resource (mappedName="demoDS")
  DataSource demoDS;
 
....
}

Have a look at JBoss EJB3 Trailblazer - Injection example
[ April 18, 2007: Message edited by: Jaikiran Pai ]

[Sreedevi Vinod]

I have read that resource injection works at both class level and field level. If the same resource is required in multiple fields, we might choose class level injection. So why isn't it working for me when I use a JNDI lookup? Like I said, it does work when I use the lookup() method of SessionContext.

Thanks,
Devi

[Jaikiran Pai]

So why isn't it working for me when I use a JNDI lookup? Like I said, it does work when I use the lookup() method of SessionContext

Sorry, misunderstood your question in the first post.

While looking up through InitialContext did you try:

Context ctx = new InitialContext();
ctx.lookup("[B]java:/demoDS[/B]");

If this doesnt work, post the contents of your -ds.xml file.

[vu lee]

Do what Jaikiran Pai suggested. If it works, it meant some how your resource was not declared under java name space. In that case, remove java name space from annotation

@Resource(name="demoDS",mappedName="demoDS")

Otherwise, you can loop through and print whatever bound to the initial context to detect the JNDI name for your datasource.

[Sreedevi Vinod]

Thanks, Jai Kiran and Vu Lee.
When I changed the code as below, it works.

   
Context ctx = new InitialContext();
DataSource demoDS = (DataSource)ctx.lookup("java:/demoDS");

Can you explain why this JNDI name is not bound to the java:comp/env namespace? What do I need to do to bind the JNDI name of the data source to java:comp/env?
Also, what is the code that I can use to loop and print out all the JNDI bindings?

Thanks,
Devi

[Jaikiran Pai]

Can you explain why this JNDI name is not bound to the java:comp/env namespace?

By default, JBoss binds your datasource to the java: namespace in the JNDI.

What do I need to do to bind the JNDI name of the data source to java:comp/env?

You can create a resource-ref entry for your application in the ejb-jar.xml and jboss.xml as follows:

Your ejb-jar.xml:

<enterprise-beans>
        <session>
 
..........
 
<resource-ref>
<description>The default DS</description>
<res-ref-name>demoDS</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
 

...........
</session>

 
</enterprise-beans>

Your jboss.xml:

<enterprise-beans>
        <session>
        .....
        <resource-ref>
<res-ref-name>demoDS</res-ref-name>
<jndi-name>java:/demoDS</jndi-name>
        </resource-ref>
 
        </session>
</enterprise-beans>

Then in your code you can access this datasouce using the java:comp/env/demoDS JNDI name.