A JDBC Driver or DataSource class name must be spe

问题:

overview : This my first tutorial by Websphere 7 Server & JPA 1.0 & EJB & Derby Database.

First : My data source name is EJB3BANK & my target database is SHOP .

Second : This the persistence.xml file

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0"
xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
<persistence-unit name="ShopJPA" transaction-type="JTA">
    <jta-data-source>jdbc/EJB3BANK</jta-data-source>
    <non-jta-data-source>jdbc/EJB3BANK</non-jta-data-source>
    <properties>
        <property name="openjpa.jdbc.Schema" value="SHOP" />
    </properties>
</persistence-unit>
</persistence> 

Third : This partial code of Item entity Class

@Entity
@Table(schema = "SHOP", name = "ITEM")
@NamedQuery(name = "getItem", query = "SELECT i FROM Item i")
public class Item{...}

Fourth : here is the business class CartBean here is the start of the problem

@Stateful
CartBean implements Cart{
....
....
public List<Item> getItems() {      
javax.persistence.Query query = em.createNamedQuery("getItem");//the problem here
return query.getResultList();
}
}

and This is the error message: A JDBC Driver or DataSource class name must be specified in the ConnectionDriverName property. How to resolve this problem?

回答1:

Used openjpa.ConnectionDriverName property is not needed if you are referring to data source by JNDI name.

One possible cause for this issue is that persistence.xml is in the wrong location. The file must be located at the [root of class context]/META-INF. For a .war file, contents should be something like:

(foo.war)
WEB-INF/classes/META-INF/persistence.xml
WEB-INF/classes/com/foo123/jpa/Project.class
WEB-INF/web.xml
index.jsp

and for a library .jar file packaged inside a .war file:

(foo.war)
WEB-INF/lib/my-library.jar
WEB-INF/web.xml
index.jsp

(my-library.jar)
META-INF/persistence.xml
com/foo123/jpa/Project.class

回答2:

the jpa message

A JDBC Driver or DataSource class name must be specified in the ConnectionDriverName property

is a misleading message. Doesn't help to understand the problem. It would be better something like:

the jta-data-source is jdbc/EJB3BANK is unavailable/unreachable

because it's what is happening. Maybe you have included a jpa project in a web or ejb project (or maybe not, you could had added the jpa facets directly to one of this kind of project) however, once you have created the jdbc connection on the webshpere console the best way to use it is:

1. change your persistence.xml (AnyJpaProject/src/META-INF/persistence.xml)

   <jta-data-source>java:comp/env/jdbc/EJB3BANK</jta-data-source>
   

2. ensure your web.xml/ejb-jar.xml has something like:

   <resource-ref>
       <description></description>
       <res-ref-name>jdbc/EJB3BANK</res-ref-name>
       <res-type>javax.sql.DataSource</res-type>
       <res-auth>Container</res-auth>
       <res-sharing-scope>Shareable</res-sharing-scope>
   </resource-ref> 
   

3. add in ibm-ejb-jar-bnd.xml/ibm-web-bnd.xml:

<resource-ref name="jdbc/EJB3BAN" binding-name="jdbc/EJB3BAN">

Hope this help.

回答3:

I think this is a bug on the implementation of the JPA provider. I am getting a similar error, but in my case I actually didn't put in the data-source name. The reason being is the standards allow for the concept of a default datasource. Unfortunately it does not work well with WebSphere Application Server 8.0.0.1 nor RSA 8.0. Not sure if a PMR has been filed either.

回答4:

Just to add to eis's answer (apologies, don't have enough rep to comment):

Using Eclipse my persistence.xml was initially located in the root src folder src/persistence.xml

Moving it to src/META-INF/persistence.xml fixed my issue as Eclipse automatically now moves it to the build directory.

Not all ORM (object relational mapping) APIs work like this though, I'm pretty sure using Hibernate my hibernate.cfg.xml (persistence.xml) was always just directly in the "src" folder.

回答5:

It is a bug not to be able to use the datasource name in the persistence.xml after adding the datasoruce in the application server. However, it will work if you add the properties in the persistence.xml as below.

    <property name="openjpa.ConnectionURL" value="DB URL"/>
    <property name="openjpa.ConnectionDriverName" value="Driver Name"/>
    <property name="openjpa.ConnectionUserName" value="userid"/>
    <property name="openjpa.ConnectionPassword" value="password"/>

回答6:

I think, what you are trying to do is to define a new Datasource by declaring it in the persistence.xml and it is missing a property like <property name="openjpa.ConnectionDriverName" value="org.apache.derby.jdbc.EmbeddedDriver" />

However as you are using Websphere I would suggest you to create the Datasource via Webspheres Administration Console (Webinterface). Under Resources->JDBC you would first create a JDBC Provider and tell it to use the Derby Driver. And after that you would create a new Datasource using this provider. There you can define the JNDI-binding. Set it to jdbc/EJB3BANK. And you current persistence.xml should work hos it is supposed to.

回答7:

try this men:

 <persistence-unit name="ShopJPA" transaction-type="JTA">
     <jta-data-source>jdbc/EJB3BANK</jta-data-source>
     <non-jta-data-source>jdbc/EJB3BANK</non-jta-data-source>
     <class>jdbc/EJB3BANK</class>
     <properties>
         <property name="openjpa.jdbc.Schema" value="SHOP" />
     </properties>
 </persistence-unit>
 </persistence> 

I don't know if must be "jdbc/EJB3BANK" or only "EJB3BANK" in the node class, try the two options. =D It works for my