No Persistence provider for EntityManager.
Bonjour,
Je débute avec JPA.
Je reçoit déjà un message d'erreur quand je lancement mon application :furax:
J'utilise le serveur MySql pour mes base de données.
Pourriez- vous me données une solution ou des pistes à suivre.
Merci
L'erreur qui est jeté:
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| log4j:WARN No appenders could be found for logger (org.hibernate.ejb.Version).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "main" javax.persistence.PersistenceException: No Persistence provider for EntityManager named helloworld
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:55)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:33)
at Application.main(Application.java:14) |
le fichier de persistence:
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<?xml version="1.0" encoding="UTF-8"?>
<persistence 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" version="1.0">
<persistence-unit name="helloworld" transaction-type="RESOURCE_LOCAL">
<!-- provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>helloworld.Message</class-->
<properties>
<property name="hibernate.archive.autodetection" value="class"/>
<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>
<property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/jpa1helloworld"/>
<property name="hibernate.connection.username" value="root"/>
<property name="hibernate.connection.password" value="root"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
<property name="hibernate.show_sql" value="true"/>
<property name="hibernate.hbm2ddl.auto" value="create-drop"/>
</properties>
</persistence-unit>
</persistence> |
et l'application
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import helloworld.Message;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
public class Application {
public static void main(String[] args) {
// same in xml file
EntityManagerFactory emf = Persistence.createEntityManagerFactory("helloworld");
EntityManager em = emf.createEntityManager();
EntityTransaction tx = em.getTransaction();
tx.begin();
Message message = new Message();
message.setText("Using JPA with Hibernate");
em.persist(message);
Message message2 = new Message();
message2.setText("Hello World");
em.persist(message2);
tx.commit();
em.close();
EntityManager newEm = emf.createEntityManager();
EntityTransaction newTx = newEm.getTransaction();
newTx.begin();
List messages = newEm.createQuery("select m from Message m order by m.text asc").getResultList();
System.out.println(messages.size() + "message(s) found:");
for(Object m : messages){
Message loadedMsg = (Message)m;
System.out.println(loadedMsg.getText());
}
newTx.commit();
newEm.close();
emf.close();
}
} |
