数据核（JDO）的Tomcat JNDI资源

Question

I have developed an application on Tomcat 7.0 that uses Datanucleus / JDO to access to a database. I currently have the JDO connection properties stored in the "datanucleus.properties" located in the application itself. The connection is working fine, but I would like to store the connection information as JNDI, to have it on the server and no longer in the war itself (I always have to replace the file in the war when deploying it remotely).

I tried the following:

1. Create a in the web.xml of the application (jdbc/ConnectionDB)

2. In "Server.xml", I tried to add the following the context of my application

    <Resource name="jdbc/ConnectionDB" auth="Container" type="javax.jdo.PersistenceManagerFactory" /> <ResourceParams name="jdbc/ConnectionDB <parameter> <name>javax.jdo.PersistenceManagerFactoryClass</name> <value>org.datanucleus.api.jdo.JDOPersistenceManagerFactory</value> </parameter> <parameter> <name>javax.jdo.option.ConnectionDriverName</name> <value>com.mysql.jdbc.Driver</value> </parameter> <parameter> <name>javax.jdo.option.ConnectionURL</name> <value>jdbc:mysql://localhost/TomcatTest</value> </parameter> ... 

3. I then try to create a new PMF with the following syntax:

   Context context = null; PersistenceManagerFactory pmf = JDOHelper.getPersistenceManagerFactory("java:comp/env/jdbc/ConnectionDB",context);

When I run my application, I get a javax.jdo.JDOUserException: You have either specified for this PMF to use a "persistence-unit" of "datanucleus.properties" (yet this doesnt exist!)

I don't really understand what is wrong in my setup.

Regards,

Marcel

Answer 1

I finally found the solution I was looking for, I post it here, it might help somebody else:

1. Create a resource in "Context.xml" file of the server

     <Resource name="jdbc/SyncTestDB" auth="Container" type="javax.sql.DataSource" maxActive="100" maxIdle="30" maxWait="10000" username="root" password="mysql" driverClassName="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost/SyncTestDB"/> 

2. Create a reference to that resource in the "web.xml" file of your application

     <resource-ref> <description>MySQL Database Connection</description> <res-ref-name>jdbc/SyncTestDB</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> </resource-ref> 

3. And finally get a Persistence Manager Factory using the JNDI connection:

    PersistenceManagerFactory pmf; Properties properties = new Properties(); properties.setProperty("datanucleus.ConnectionFactoryName","java:comp/env/jdbc/SyncTestDB"); 

Answer 2

Read the javadoc for JDOHelper.getPersistenceManagerFactory(String) and it is obviously not for passing in some JNDI data source string.

Read the docs for Tomcat and you will also see that specifying a datasource you do not provide JDO connection details.

You can equally specify a persistence.xml with that JNDI string for the "javax.jdo.option.ConnectionFactoryName" property. As per the JDO spec and DataNucleus/Tomcat docs then