[jboss-user] [EJB 3.0 Users] - How to find Entity by Id
Fuchs
do-not-reply at jboss.com
Fri Nov 13 10:08:22 EST 2009
Hello,
i am using jboss portal 2.7.2 bundle with jboss 4.2.3 and i like to use ejb3 persistence for database query.
But i get this exception:
15:45:31,530 ERROR [CustomerHome] get failed
| java.lang.NullPointerException
| at swk.hibernate.dao.CustomerHome.findById(Unknown Source)
| at de.counter.CounterBean.<init>(CounterBean.java:69)
My datasource:
<datasources>
| <local-tx-datasource>
| <jndi-name>HelloWorldDS</jndi-name>
| <connection-url>jdbc:mysql://xxxx/xxxx</connection-url>
| <driver-class>com.mysql.jdbc.Driver</driver-class>
| <user-name>xxxx</user-name>
| <password>xxxx</password>
| <min-pool-size>5</min-pool-size>
| <max-pool-size>20</max-pool-size>
| </local-tx-datasource>
| </datasources>
persistence.xml:
<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="customerdb">
| <provider>org.hibernate.ejb.HibernatePersistence</provider>
| <jta-data-source>java:/HelloWorldDS</jta-data-source>
| <properties>
| <property name="hibernate.archive.autodetection" value="class, hbm"></property>
| <property name="hibernate.show_sql" value="true"/>
| <property name="hibernate.format_sql" value="true"/>
| <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
| </properties>
| </persistence-unit>
| </persistence>
|
and the entity with Stateless Home Class:
CustomerEntity
| @Entity
| @Table(name = "Customer", catalog = "swkcustomerportal")
| public class Customer implements java.io.Serializable {
|
| private Integer idCustomer;
| private String jbossUser;
| ...
|
| public Customer() {
| }
|
| public Customer(String jbossUser, ...) {
| this.jbossUser = jbossUser;
| ...
| }
|
| public Customer(String jbossUser, ....)
| ...
| }
|
| @Id
| @GeneratedValue(strategy = IDENTITY)
| @Column(name = "idCustomer", unique = true, nullable = false)
| public Integer getIdCustomer() {
| return this.idCustomer;
| }
|
| protected void setIdCustomer(Integer idCustomer) {
| this.idCustomer = idCustomer;
| }
| ...
|
| CustomerHomeStateless
| @Stateless
| public class CustomerHome {
|
| private static final Log log = LogFactory.getLog(CustomerHome.class);
|
| @PersistenceContext(unitName="customerdb")
| private EntityManager entityManager;
|
| public void persist(Customer transientInstance) {
| ...
| }
|
| public void remove(Customer persistentInstance) {
| ...
| }
|
| public Customer merge(Customer detachedInstance) {
| ...
| }
|
| public Customer findById(Integer id) {
| log.debug("getting Customer instance with id: " + id);
| try {
|
| Customer instance = (Customer)entityManager.find(Customer.class, id);
| log.debug("get successful");
| return instance;
| } catch (RuntimeException re) {
| log.error("get failed", re);
| throw re;
| }
| }
| }
I shorted the Classes to give an easier overview.
The Customer and the CustomerHome are in different packages of the same jar File. I thought that it is no problem.
Jboss Console gives me the following information:
| 15:28:33,054 INFO [JmxKernelAbstraction] creating wrapper delegate for: org.jboss.ejb3.entity.PersistenceUnitDeployment
| 15:28:33,070 INFO [JmxKernelAbstraction] installing MBean: persistence.units:jar=HibernateCustomer.jar,unitName=customerdb with dependencies:
| 15:28:33,070 INFO [JmxKernelAbstraction] jboss.jca:name=HelloWorldDS,service=DataSourceBinding
| 15:28:33,086 INFO [PersistenceUnitDeployment] Starting persistence unit persistence.units:jar=HibernateCustomer.jar,unitName=customerdb
| 15:28:33,164 INFO [Version] Hibernate EntityManager 3.2.1.GA
| 15:28:33,164 INFO [Version] Hibernate Annotations 3.2.1.GA
| 15:28:33,351 INFO [Ejb3Configuration] found EJB3 Entity bean: swk.hibernate.model.Customer
| ...
| 15:28:34,773 INFO [HbmBinder] Mapping class: swk.hibernate.model.Customer -> Customer
| ...
| 15:28:36,273 INFO [SessionFactoryObjectFactory] Factory name: persistence.units:jar=HibernateCustomer.jar,unitName=customerdb
| 15:28:36,273 INFO [NamingHelper] JNDI InitialContext properties:{java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory, java.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfaces}
| 15:28:36,289 INFO [SessionFactoryObjectFactory] Bound factory to JNDI name: persistence.units:jar=HibernateCustomer.jar,unitName=customerdb
| 15:28:36,289 WARN [SessionFactoryObjectFactory] InitialContext did not implement EventContext
| 15:28:36,289 INFO [NamingHelper] JNDI InitialContext properties:{java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory, java.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfaces}
| 15:28:36,742 INFO [JmxKernelAbstraction] creating wrapper delegate for: org.jboss.ejb3.stateless.StatelessContainer
| 15:28:37,039 INFO [JmxKernelAbstraction] installing MBean: jboss.j2ee:jar=HibernateCustomer.jar,name=CustomerHome,service=EJB3 with dependencies:
| 15:28:37,039 INFO [JmxKernelAbstraction] persistence.units:jar=HibernateCustomer.jar,unitName=customerdb
| 15:28:37,055 INFO [EJBContainer] STARTED EJB: swk.hibernate.dao.CustomerHome ejbName: CustomerHome
| 15:28:37,055 INFO [JmxKernelAbstraction] creating wrapper delegate for: org.jboss.ejb3.stateless.StatelessContainer
| ...
| 15:28:37,289 INFO [EJB3Deployer] Deployed: file:/D:/server/jboss-portal-2.7.2/server/default/deploy/HibernateCustomer.jar
My portlet does the following:
Customer customers;
| ...
|
| public CounterBean() {
| ...
| try {
| customers = (Customer) new CustomerHome().findById(1);
| ...
I must omit something, or I did not understand it correctly.
Can someone help me?
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