Hi, if You defined more persistence units in Your persistence.xml file you should inject the EntityManager by @Inject @PersistenceContext(unitName = "unitname")
2013/10/11 Andreas Ernst <a...@ae-online.de>: > Am 11.10.13 12:55, schrieb Dmitry Gusev: > >> Have you read this? >> http://tapestry.apache.org/integrating-with-jpa.html >> >> You should @Inject EntityManager, if you do things right you won't have to >> create EntityManager instances yourself. >> >> Also, saying that you have NPE, it would be nice if you provide us a >> stacktrace. >> >> >> On Fri, Oct 11, 2013 at 2:48 PM, Andreas Ernst <a...@ae-online.de> wrote: >> >>> Hi, >>> >>> i am playing with JPA, but there is no useful information about that. A >>> simple example to display a database table. >>> >>> The entities class is in the right package entities. I did not added >>> something to the AppModule class. The persistence.xml exists. >>> >>> Customer.tml >>> >>> <html t:type="layout" title="Customer" >>> >>> xmlns:t="http://tapestry.**apache.org/schema/tapestry_5_**3.xsd<http://tapestry.apache.org/schema/tapestry_5_3.xsd> >>> " >>> xmlns:p="tapestry:parameter"> >>> <table t:type="grid" source="customers"/> >>> </html> >>> >>> >>> Customers.class >>> >>> public class Customers { >>> >>> @Property >>> private Customer customer; >>> private EntityManagerFactory factory; >>> private EntityManager entityManager; >>> @Inject >>> private Logger logger; >>> @Inject >>> private BeanModelSource beanModelSource; >>> @Inject >>> private Messages messages; >>> >>> @Log >>> public List<Customers> getCustomers() { >>> factory = Persistence.**createEntityManagerFactory("** >>> de.aeits_TapestryWeb_war_1.0-**SNAPSHOTPU"); >>> entityManager = factory.createEntityManager(); >>> return entityManager.**createNamedQuery("Customer.** >>> findAll").getResultList(); >>> } >>> } >>> >>> >>> What about the DAO and DAOImpl there are no informations how to use this >>> classes with a simple query page. >>> >>> In all docus i found only >>> 'entityManager.**createNamedQuery("Customer.**findAll").getResultList();' >>> is needed, but i get a null pointer expection. > > > Yes, i read that. > > > public class Customers { > > @Property > private Customer customer; > @Inject > private EntityManager entityManager; > > public List<Customers> getCustomers() { > return > entityManager.createNamedQuery("Customer.findAll").getResultList(); > } > } > > java.lang.RuntimeException: Unable to locate a single EntityManager. You > must provide the persistence unit name as defined in the persistence.xml > using the @PersistenceContext annotation. > at > org.apache.tapestry5.internal.jpa.JpaInternalUtils.getEntityManager(JpaInternalUtils.java:92) > at > org.apache.tapestry5.internal.jpa.EntityManagerObjectProvider$1.createObject(EntityManagerObjectProvider.java:62) > > > -- > ae | Andreas Ernst | IT Spektrum > Postfach 5, 65612 Beselich > Schupbacher Str. 32, 65614 Beselich, Germany > Tel: +49-6484-91002 Fax: +49-6484-91003 > a...@ae-online.de | www.ae-online.de > www.tachyon-online.de > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tapestry.apache.org > > For additional commands, e-mail: users-h...@tapestry.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tapestry.apache.org For additional commands, e-mail: users-h...@tapestry.apache.org
