Quindi ho due bean semplici: FatKid e Hamburger. Ora, per ragioni a mia insaputa, devo essere in grado non solo di guardare tutti gli hamburger che qualcuno ha mangiato, ma anche di mangiare quel particolare hamburger. Sul codice!Hibernate e H2 "Violazione del vincolo di integrità referenziale" per OneToMany mapping bidirezionale
FatKid.java
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.Table;
@Table
@Entity
public class FatKid {
private int id;
private String name;
private List<Hamburger> hamburgers;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "FATKID_ID")
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Column
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name="HAMBURGER_ID")
public List<Hamburger> getHamburgers() {
return hamburgers;
}
public void setHamburgers(List<Hamburger> hamburgers) {
this.hamburgers = hamburgers;
}
}
Hamburger.java
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
@Table
@Entity
public class Hamburger {
private int id;
private String description;
private FatKid whoDoneAteMe;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "HAMBURGER_ID")
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Column
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name="FATKID_ID")
public FatKid getWhoDoneAteMe() {
return whoDoneAteMe;
}
public void setWhoDoneAteMe(FatKid whoDoneAteMe) {
this.whoDoneAteMe = whoDoneAteMe;
}
}
hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">org.h2.Driver</property>
<property name="hibernate.connection.url">jdbc:h2:~/routesetting</property>
<property name="hibernate.dialect">org.hibernate.dialect.H2Dialect</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">create-drop</property>
<mapping class="FatKid" />
<mapping class="Hamburger" />
</session-factory>
</hibernate-configuration>
dipendenze
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>3.6.7.Final</version>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<version>1.3.160</version>
</dependency>
<dependency>
<groupId>javassist</groupId>
<artifactId>javassist</artifactId>
<version>3.9.0.GA</version>
</dependency>
cliente
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class OmNom {
private static final SessionFactory sessionFactory = buildSessionFactory();
public static void main(String[] args) {
Session session = sessionFactory.openSession();
session.beginTransaction();
FatKid fk = new FatKid();
fk.setName("Darrell");
session.save(fk);
session.getTransaction().commit();
session.beginTransaction();
Hamburger hamburger_1 = new Hamburger();
hamburger_1.setDescription("Juicy quarter pounder with cheese");
hamburger_1.setWhoDoneAteMe(fk);
session.save(hamburger_1);
session.getTransaction().commit();
session.beginTransaction();
Hamburger hamburger_2 = new Hamburger();
hamburger_2.setDescription("Ground buffalo burger topped with bacon and a sunny-side egg");
hamburger_2.setWhoDoneAteMe(fk);
session.save(hamburger_2);
session.getTransaction().commit();
sessionFactory.close();
}
private static SessionFactory buildSessionFactory() {
try {
// Create the SessionFactory from hibernate.cfg.xml
return new Configuration().configure().buildSessionFactory();
}
catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
throw new ExceptionInInitializerError(ex);
}
}
}
Così, quando ho eseguito il codice che finiscono con l'uscita (e troncato stack trace)
Hibernate: insert into FatKid (FATKID_ID, name) values (null, ?)
Hibernate: insert into Hamburger (HAMBURGER_ID, description, FATKID_ID) values (null, ?, ?)
Hibernate: insert into Hamburger (HAMBURGER_ID, description, FATKID_ID) values (null, ?, ?)
Exception in thread "main" org.hibernate.exception.ConstraintViolationException: could not insert: [Hamburger]
...
Caused by: org.h2.jdbc.JdbcSQLException: Referential integrity constraint violation: "FK43797FE95067143: PUBLIC.HAMBURGER FOREIGN KEY(HAMBURGER_ID) REFERENCES PUBLIC.FATKID(FATKID_ID)"; SQL statement:
insert into Hamburger (HAMBURGER_ID, description, FATKID_ID) values (null, ?, ?) [23506-160]
...
Quindi la prima Hamburger è salvato, ma poi fa saltare in aria al secondo. Entrambi dovrebbero essere in grado di utilizzare l'id di FatKid come chiave esterna ma non sembra funzionare. Qualsiasi intuizione sarebbe molto apprezzata.
Grazie, Kevin
Grazie mille, la rimozione di @JoinColumn e l'aggiunta del mappedBy hanno funzionato. – Kevin