Re: Web app with jpa -- configuration help needed

Fri, 15 Jun 2007 12:37:36 -0700 

I'm not sure jays' info is correct.
You can get an EntityManager in a servlet as long as you look it up in jndi, just don't inject it using annotations or cache it in a field in your servlet. 


I think the problem is that you are looking up java:comp/env/jdbc/ 
jBasicDB which is where the datasource is expected to be, not the  
EntityManager.  Also in your geronimo plan you have a persistence- 
unit-ref specified but you want a persistence-context-ref since you  
are looking for an EntityManager, not an EntityManagerFactory.



I would suggest that you look up java:comp/env/jBasicDB in your  
servlet, and include this in your web.xml and then you won't need  
anything in your geronimo-web plan:


<persistence-context-ref>

    <persistence-context-ref-name>jBasicDB</persistence-context-ref- 
name>

    <!-- I can't remember if anything else is required -->
</persistence-context-ref>


Also I strongly recommend including a non-jta-datasource in the  
persistence.xml, I haven't been able to get anything to work with  
derby without that.  mysql may be more forgiving/less prone to weird  
deadlocks.  Leave out all the connect-to-mysql parameters in  
persistence.xml and use the datasource.



You don't need a resource-ref anywhere if you aren't using the db  
directly from your servlet.



I assume you've found the jpa sample under testsuite/.....? It uses  
derby but does show a (usually) working configuration.


Hope this helps
david jencks

On Jun 15, 2007, at 12:20 PM, Jay D. McHugh wrote:


Peter,


I just realized - if you are doing resource_local access, you don't  
actually need the database pool.


OpenJPA will create connections as it needs them.


I would leave the database pool there though - it doesn't hurt  
anyone having it there.



Once you manage to get your app deployed, take a look in the jmx  
viewer of the admin console under J2EE Managed Objects/Persistence  
Unit to make sure it got deployed correctly.  Also, when you  
deploy, there will be a message dumped to the log about a property  
being unrecognized - you can ignore it.  It is an issue with  
OpenJPA that already has a JIRA filed for it.



Make sure you have the synchronizeMappings property set in your  
persistence.xml - otherwise the Geronimo default will kick in and  
try to recreate your tables and destroy all of your data.



If I have time to try fixing my app to use the jta datasource -  
I'll let you know what needs to change.



Jay

Jay D. McHugh wrote:

Hi Peter,


In a webapp, you are not allowed to directly get an EntityManager  
(they aren't threadsafe).  Instead, you need to get an  
EntityManagerFactory.



I was originally not able to get access to a jta-datasource, I had  
to go with resource-local.  I never went back to try accessing a  
database pool - so I'm going to tell you how I got things working  
in my current setup (using your values).


_persistence.xml

_<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence";

   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";  
version="1.0"
   xsi:schemaLocation="http://java.sun.com/xml/ns/persistence  
http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd";>
   <persistence-unit transaction-type="RESOURCE_LOCAL"  
name="jbasicDB">
        
<provider>org.apache.openjpa.persistence.PersistenceProviderImpl</ 
provider>

       <class>nu.m4u.jbasic.control.jpa.Users</class>
       <exclude-unlisted-classes />
       <properties>

           <property name="openjpa.ConnectionURL"  
value="jdbc:mysql://localhost:3306/jbasic"/>
           <property name="openjpa.ConnectionDriverName"  
value="com.mysql.jdbc.Driver"/>
           <property name="openjpa.ConnectionUserName"  
value="xxxxx"/>
           <property name="openjpa.ConnectionPassword"  
value="xxxxx"/>
           <property name="openjpa.Log" value="DefaultLevel=WARN,  
Tool=INFO"/>
           <property name="openjpa.jdbc.DBDictionary" value="mysql 
(SupportsSubselect=true)" />

           <property name="openjpa.Log" value="DefaultLevel=INFO" />
           <property name="openjpa.AutoDetach" value="close" />
           <property name="openjpa.DetachState" value="all" />
           <property name="openjpa.DataCache" value="false" />
           <property name="openjpa.Optimistic" value="true" />
           <property name="openjpa.Multithreaded" value="true" />
           <property name="openjpa.TransactionMode" value="local" />

           <property name="openjpa.NontransactionalRead"  
value="true" />

           <property name="openjpa.RestoreState" value="all" />

           <property name="openjpa.jdbc.SynchronizeMappings"  
value="false" />

       </properties>
   </persistence-unit>
</persistence>

_geronimo-web.xml:_

Remove all of the persistence unit info ->

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://geronimo.apache.org/xml/ns/j2ee/web-1.2";
       xmlns:nam="http://geronimo.apache.org/xml/ns/naming-1.1";
       xmlns:sec="http://geronimo.apache.org/xml/ns/security-1.1";
       xmlns:sys="http://geronimo.apache.org/xml/ns/deployment-1.1";>
<sys:environment>
  <sys:moduleId>
    <sys:groupId>jbasic</sys:groupId>
    <sys:artifactId>jbasic2</sys:artifactId>
    <sys:type>war</sys:type>
  </sys:moduleId>
  <sys:dependencies>
    <sys:dependency>
       <sys:groupId>console.dbpool</sys:groupId>
       <sys:artifactId>jbasicDB</sys:artifactId>
       <sys:version>1.0</sys:version>
       <sys:type>rar</sys:type>
    </sys:dependency>         <sys:dependency>
      <sys:groupId>mysql</sys:groupId>
      <sys:artifactId>mysql-connector-java</sys:artifactId>
      <sys:version>3.1.12</sys:version>
      <sys:type>jar</sys:type>
       </sys:dependency>
</sys:dependencies>
</sys:environment>
<context-root>/jbasic2</context-root>
</web-app>

_web.xml:_

Remove the peristence info.

_database pool plan:_

looks fine



Then, in order to get an EntityManagerFactory in your servlets use  
resource injection to create a class variable:



   @PersistenceUnit(unitName="jbasicDB") private  
EntityManagerFactory emf;


And finally, wherever you need access to an EntityManager:

EntityManager em = emf.createEntityManager();

em.getTransaction().begin();

// do stuff

em.getTransaction().commit();

em.close();


If you are only reading from your database, you can leave off the  
'em.getTransaction()' stuff.  But if you are modifying data - you  
will need these otherwise, when you close your EntityManager  
instances all of your changes go away.


Hope this helps,


Jay

Peter Petersson wrote:

Hi

Need help on resolving the following configuration problem.

I am trying to find out how to get a geronimo database pool  
(mysql) used in a webapp, JPA managed in G v2.0 M6 (this is just  
a WAR not a EAR).


I end up stuck at deployment with the following error message.

13:42:42,291 ERROR [Deployer] Deployment failed due to

org.apache.geronimo.common.DeploymentException: At least one  
deployment problem: 
[org.apache.geronimo.common.DeploymentException: Could not  
resolve reference at deploy time for query ? 
name=jbasicDB#org.apache.geronimo.persistence.PersistenceUnitGBean.  
No GBean references found.]
       at  
org.apache.geronimo.persistence.builder.PersistenceUnitRefBuilder.bu 
ildNaming(PersistenceUnitRefBuilder.java:154)
       at  
org.apache.geronimo.persistence.builder.PersistenceUnitRefBuilder$ 
$FastClassByCGLIB$$9679ec9.invoke(<generated>)



I have looked around for G/JPA configuration information but the  
ones I have found aether deals with G:s derby db (examples  
working fine) or is a fully fledged EAR application which is a  
bit of an overkill as this app is meant to be used as a  
educational "stepping stone" app for some colleagues ( and me as  
it seems ;) ).



I'm trying to get hold of the entity manager with the following  
JNDI context lookup name "java:comp/env/jdbc/jbasicDB"



Here is relevant (or not so) parts of the current incarnation of  
the configuration:


persistency.xml (in webapp/WEB-INF)
------------------------------------------------
<persistence xmlns="http://java.sun.com/xml/ns/persistence";
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
            version="1.0"

            xsi:schemaLocation="http://java.sun.com/xml/ns/ 
persistence http://java.sun.com/xml/ns/persistence/ 
persistence_1_0.xsd">


 <persistence-unit name="jbasicDB" transaction-type="JTA">

   
<provider>org.apache.openjpa.persistence.PersistenceProviderImpl</ 
provider>

  <jta-data-source>jdbc/jbasicDB</jta-data-source>
  <class>nu.m4u.jbasic.control.jpa.Users</class>
  <exclude-unlisted-classes/>
   <properties>

    <property name="openjpa.jdbc.DBDictionary"  
value="org.apache.openjpa.jdbc.sql.MySQLDictionary"/>
     <property name="openjpa.ConnectionURL" value="jdbc:mysql:// 
localhost:3306/jbasic"/>
     <property name="openjpa.ConnectionDriverName"  
value="com.mysql.jdbc.Driver"/>

     <property name="openjpa.ConnectionUserName" value="xxxxx"/>
     <property name="openjpa.ConnectionPassword" value="xxxxx"/>

     <property name="openjpa.Log" value="DefaultLevel=WARN,  
Tool=INFO"/>

   </properties>    </persistence-unit>
</persistence>
------------------------------------------------

geronimo-web.xml
------------------------------------------------
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://geronimo.apache.org/xml/ns/j2ee/web-1.2";
        xmlns:nam="http://geronimo.apache.org/xml/ns/naming-1.1";
        xmlns:sec="http://geronimo.apache.org/xml/ns/security-1.1";

        xmlns:sys="http://geronimo.apache.org/xml/ns/ 
deployment-1.1">

 <sys:environment>
   <sys:moduleId>
     <sys:groupId>jbasic</sys:groupId>
     <sys:artifactId>jbasic2</sys:artifactId>
     <sys:type>war</sys:type>
   </sys:moduleId>
   <sys:dependencies>
     <sys:dependency>
        <sys:groupId>console.dbpool</sys:groupId>
        <sys:artifactId>jbasicDB</sys:artifactId>
        <sys:version>1.0</sys:version>
        <sys:type>rar</sys:type>
     </sys:dependency>         <sys:dependency>
       <sys:groupId>mysql</sys:groupId>
       <sys:artifactId>mysql-connector-java</sys:artifactId>
       <sys:version>3.1.12</sys:version>
       <sys:type>jar</sys:type>        </sys:dependency>
     <!--        <sys:dependency>
        <sys:groupId>org.apache.geronimo.configs</sys:groupId>
        <sys:artifactId>openjpa</sys:artifactId>
        <sys:type>car</sys:type>
     </sys:dependency>
     -->            </sys:dependencies>       </sys:environment>

 <context-root>/jbasic2</context-root>

 <persistence-unit-ref>

    <persistence-unit-ref-name>jdbc/jbasicDB</persistence-unit- 
ref-name>

    <persistence-unit-name>jbasicDB</persistence-unit-name>
 </persistence-unit-ref>

<!--        <sys:resource-ref>
    <sys:ref-name>jdbc/jbasicDB</sys:ref-name>
    <sys:resource-link>jbasicDB</sys:resource-link>
 </sys:resource-ref>
-->  </web-app>   ------------------------------------------------

web.xml
------------------------------------------------
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4"
   xmlns="http://java.sun.com/xml/ns/j2ee";
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";

   xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http:// 
java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

   <!-- Nothing much here yet -->    <!--         <resource-ref>
       <res-ref-name>jdbc/jbasicDB</res-ref-name>
       <res-type>javax.sql.DataSource</res-type>
       <res-auth>Container</res-auth>
       <res-sharing-scope>Shareable</res-sharing-scope>

   </resource-ref>    -->          </web-app>     
------------------------------------------------


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

<connector xmlns="http://geronimo.apache.org/xml/ns/j2ee/ 
connector-1.2">
   <dep:environment xmlns:dep="http://geronimo.apache.org/xml/ns/ 
deployment-1.2">

       <dep:moduleId>
           <dep:groupId>console.dbpool</dep:groupId>
           <dep:artifactId>jbasicDB</dep:artifactId>
           <dep:version>1.0</dep:version>
           <dep:type>rar</dep:type>
       </dep:moduleId>
       <dep:dependencies>
           <dep:dependency>
               <dep:groupId>mysql</dep:groupId>
               <dep:artifactId>mysql-connector-java</dep:artifactId>
               <dep:version>3.1.12</dep:version>
               <dep:type>jar</dep:type>
           </dep:dependency>
       </dep:dependencies>
   </dep:environment>
   <resourceadapter>
       <outbound-resourceadapter>
           <connection-definition>

               <connectionfactory-interface>javax.sql.DataSource</ 
connectionfactory-interface>

               <connectiondefinition-instance>
                   <name>jbasicDB</name>

                   <config-property-setting name="Password">xxxx</ 
config-property-setting>
                   <config-property-setting  
name="Driver">com.mysql.jdbc.Driver</config-property-setting>
                   <config-property-setting name="UserName">xxxx</ 
config-property-setting>
                   <config-property-setting  
name="ConnectionURL">jdbc:mysql://localhost:3306/jbasic</config- 
property-setting>

                   <connectionmanager>
                       <local-transaction/>
                       <single-pool>
                           <max-size>10</max-size>
                           <min-size>0</min-size>
                           <match-one/>
                       </single-pool>
                   </connectionmanager>
               </connectiondefinition-instance>
           </connection-definition>
       </outbound-resourceadapter>
   </resourceadapter>
</connector>
------------------------------------------------

Anny help is appreciated !
/Peter Petersson































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