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Eclipse Authors: Pat Romanski, Elizabeth White, Liz McMillan, David H Deans, JP Morgenthal

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Java IoT: Article

Generating Spring ORM Classes – Part 6

Configuring the project to use Spring framework

In Part 5 I  explored persistence settings. The persistence.xml file defines the context for JPA persistence.  In Part 6, we will configure the project to use Spring framework and generate Spring ORM classes to access the entities created earlier.

The tasks you will complete in this step are:

Add Spring Facet to project

  1. Right click on the project oepe-jpa-tutorial. Select Properties, click Project Facets, and check Spring Facet. Click Further configuration.. link. Select the Spring library that will be used with this project and click finish to install Spring Facet.

Generate Spring ORM classes

  1. Right click on the project oepe-jpa-tutorial. Select New > Generate Spring ORM classes

  1. Click Add to add a new Spring ORM service to use the JPA entities. Fill in the required fields as illustrated.

  1. Click Next to select Use plain JPA for DAO implementation and click Finish to finish generating Spring service class and DAO class.

Review generated Spring service bean and DAO classes

  1. From the Project Explorer, expand Spring Elements to review the Spring configuration.
  2. Spring beans used to access the JPA entities are generated into oracle.spring package.

Connecting Entities to a User Interface
In this step, you will import a Web application that incorporates the database connection, entities, and Spring classes you have created in this tutorial. This application includes JPA entities, Spring service beans, DAO classes, JSPs, and servlets. After importing the application, you will create a new server and run the application.

The tasks you will complete in this step are:

Import the Web application

  1. Import web.zip into the Web application oepe-jpa-tutorial.
  2. Right click on the project oepe-jpa-tutorial. Select Import > General > Archive File and click Next. Browse to the location where you decided to download web.zip and click Finish. Overwrite any and all files as you import.

Review the application components
The imported application includes a JSP page and a managed bean. The project also contains a faces-config.xml file, which manages the navigation of the application and the JSPs that comprise the user interface.

Now, let's review the MVC connection strategy, which is to use Spring DAO through a JSF Managed Bean.

The web/WEB-INF/config folder contains the faces-config.xml file that configures the Managed Bean configurations and Navigation Rules for the Web application.

  1. Double click the faces-config.xml file to open the Faces Config Editor. Note that Customer and customerManagedBean are defined as managed beans in the request scope.

  1. Navigation Rules are defined for addCustomer.jsp and viewAllCustomers.jsp. The navigation case for addCustomer.jsp specifies /pages/viewAllCustomers.jsp as the destination page while the outcome is success.

  1. Similarly, the navigation case for viewAllCustomers.jsp describes /pages/viewOrders.jsp as the destination page while the outcome is orderList.

Create a new server

Now you will create a server to use to run your completed sample application. If one exists already in the Servers tab, delete it.

  1. In the Java EE perspective, the following views should be visible as tabs at the bottom (by default) of Oracle Enterprise Pack for Eclipse: Problems, Tasks, Properties, Servers, Database Explorer, Snippets.
  2. Click the Servers view tab, right-click in its window, and then click New > Server.

  1. In the New Server dialog, under Select the server type, confirm that Oracle > Oracle WebLogic Server v11gR1 is selected, and then click Next.
  2. In the Domain home box, ensure that the dropdown shows the domain directory as the following:

C:\<middleware home>\wlserver_10.3\samples\domains\wl_server

  1. Click Finish.

Undeploy previous tutorial code
Oracle WebLogic Server does not support the deployment of projects with the same name from two different locations on disk.

For this reason, any time you deploy a sample or run through a tutorial, you should check your server for previous deployments of the same code. If your server already has a deployment of the sample or tutorial code, you should undeploy any previous code.

Run the JPA Web application

  1. After the server starts successfully, open a browser. Enter the address http://localhost:7001/oepe-jpa-tutorial/pages/addCustomer.jsf in the address line of the browser pane to view the addCustomer.jsf page in the browser (if necessary).

  2. Enter the name Bob and click Submit to add a new customer named Bob.

The application calls addCustomer( ) action method of the CustomerManagedBean and forwards the request to viewAllCustomers.jsp, if the customer is added successfully. The viewAllCustomers.jsp gets the customers list using the <h:dataTable> component and displays it as shown below.

  1. Click View Orders for the customer name JOHN to get the list of order(s) placed by JOHN.

  2. Click Back to browse to the previous page and view orders placed by other customers.
  3. Once you are done, stop the server.

Troubleshooting

  1. Not able to commit the changes. Oracle WebLogic Server throws exception:
  2. Caused by: javax.persistence.RollbackException: Transaction rolled back because transaction was set to RollbackOnly.
  3. at org.eclipse.persistence.internal.jpa.transaction. EntityTransactionImpl.commitInternal(EntityTransactionImpl.java:92)
  4. at org.eclipse.persistence.internal.jpa.transaction. EntityTransactionImpl.commit(EntityTransactionImpl.java:63)
  5. at org.springframework.orm.jpa.JpaTransactionManager. doCommit(JpaTransactionManager.java:456)

Please make sure the database connection properties in persistence.xml are correct.

  1. Oracle WebLogic Server complains "No Persistence provider for EntityManager"
  2. javax.persistence.PersistenceException: No Persistence provider for EntityManager named unitK:  The following providers:
  3. org.eclipse.persistence.jpa.PersistenceProvider
  4. kodo.persistence.PersistenceProviderImpl
  5. org.apache.openjpa.persistence.PersistenceProviderImpl
  6. Returned null to createEntityManagerFactory.

Please make sure the persistence unit name referenced in Spring applicationContext.xml is same as the one defined in JPA persistence.xml, e.g. "oepe-jpa-tutorial."

More Stories By Pieter Humphrey

Pieter Humphrey has been at Oracle (by way of BEA Systems) for 7+ years, working in development, marketing, sales, and developer relations to advance Java technology in the enterprise. He ran the dev2dev community at BEA and continues to with work with Oracle OTN and Eclipse Foundation communities. His current role is focused on application development tools like Oracle Enterprise Eclipse Pack, Oracle Workshop for WebLogic, JDeveloper, TopLink and the ADF framework, and is a frequent speaker at industry events and workshops.

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