Я хочу создать минималистичное локальное приложение, которое читает / записывает HBase через JPA2 без orm.xml и без maven2.
Тем самым я использую Eclipse с плагином DataNucleus, чей Enhancer включен для проекта.
Вдохновлен
http://matthiaswessendorf.wordpress.com/2010/03/17/apache-hadoop-hbase-plays-nice-with-jpa/
Я получил следующие сущности:
@Entity
@Table(name="account_table")
public class Account
{
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private String id;
String firstName = null;
String lastName = null;
int level = 0;
@Embedded
Login login = null;
public Account() { }
public Account(String firstName, String lastName, int level, Login login) {
super();
this.firstName = firstName;
this.lastName = lastName;
this.level = level;
this.login = login;
}
и
@Embeddable
public class Login
{
private String login = null;
private String password = null;
public Login() {
// TODO Auto-generated constructor stub
}
public Login(String login, String password) {
super();
this.login = login;
this.password = password;
}
}
src / META-INF / persistence.xml
<persistence
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
version="1.0">
−
<persistence-unit name="hbase-addressbook"
transaction-type="RESOURCE_LOCAL">
<class>de.syrtec.jpa2hbase.entities.Login</class>
<class>de.syrtec.jpa2hbase.entities.Account</class>
<properties>
<property name="datanucleus.ConnectionURL" value="hbase" />
<property name="datanucleus.ConnectionUserName" value="" />
<property name="datanucleus.ConnectionPassword" value="" />
<property name="datanucleus.autoCreateSchema" value="true" />
<property name="datanucleus.validateTables" value="false" />
<property name="datanucleus.Optimistic" value="false" />
<property name="datanucleus.validateConstraints" value="false" />
</properties>
</persistence-unit>
</persistence>
ДАО:
public class TestDAO {
public static void main(String[] args) {
EntityManagerFactory emf = Persistence.createEntityManagerFactory("hbase-addressbook");
EntityManager em = emf.createEntityManager();
EntityTransaction tx = null;
Account a1 = new Account("myPre", "mySur", 1, new Login("a", "b"));
tx = em.getTransaction();
tx.begin();
em.persist(a1);
tx.commit();
}
}
Но когда выполняется первая строка теста DAO ...
EntityManagerFactory emf = Persistence.createEntityManagerFactory("hbase-addressbook");
.. Я получаю:
11/09/01 06:57:05 INFO DataNucleus.MetaData: Class "de.syrtec.jpa2hbase.entities.Account" has been specified with JPA annotations so using those.
11/09/01 06:57:05 INFO DataNucleus.MetaData: Class "de.syrtec.jpa2hbase.entities.Login" has been specified with JPA annotations so using those.
Exception in thread "main" javax.persistence.PersistenceException: Explicit persistence provider error(s) occurred for "hbase-addressbook" after trying the following discovered implementations: org.datanucleus.api.jpa.PersistenceProviderImpl from provider: org.datanucleus.api.jpa.PersistenceProviderImpl
at javax.persistence.Persistence.createPersistenceException(Persistence.java:242)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:184)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:70)
at de.syrtec.jpa2hbase.start.TestDAO.main(TestDAO.java:15)
Caused by: org.datanucleus.exceptions.NucleusUserException: Errors were encountered when loading the MetaData for the persistence-unit "hbase-addressbook". See the nested exceptions for details
at org.datanucleus.metadata.MetaDataManager.loadPersistenceUnit(MetaDataManager.java:879)
at org.datanucleus.api.jpa.JPAEntityManagerFactory.initialiseNucleusContext(JPAEntityManagerFactory.java:745)
at org.datanucleus.api.jpa.JPAEntityManagerFactory.<init>(JPAEntityManagerFactory.java:422)
at org.datanucleus.api.jpa.PersistenceProviderImpl.createEntityManagerFactory(PersistenceProviderImpl.java:91)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:150)
... 2 more
Caused by: org.datanucleus.exceptions.ClassNotResolvedException: Class "−
de.syrtec.jpa2hbase.entities.Login" was not found in the CLASSPATH. Please check your specification and your CLASSPATH.
at org.datanucleus.JDOClassLoaderResolver.classForName(JDOClassLoaderResolver.java:247)
at org.datanucleus.JDOClassLoaderResolver.classForName(JDOClassLoaderResolver.java:412)
at org.datanucleus.metadata.MetaDataManager.loadPersistenceUnit(MetaDataManager.java:859)
... 6 more
Перед тем, как запустить DAO, я успешно запустил класс, улучшающий datanucleus:
DataNucleus Enhancer (version 3.0.0.release) : Enhancement of classes
DataNucleus Enhancer completed with success for 2 classes. Timings : input=623 ms, enhance=101 ms, total=724 ms. Consult the log for full details
Хотя я не понимаю, что расширение не запускается автоматически (со ссылкой на журналы), несмотря на то, что для проекта активировано автоматическое улучшение.
Кто-нибудь знает, почему мои сущности не найдены?