Hibernate Mapping One-to-Many using Annotations Part -2

The @OneToMany annotation is used to create the one-to-many relationship between the Student andPhone entities. The @JoinTable annotation is used to create the STUDENT_PHONE link table and@JoinColumn annotation is used to refer the linking columns in both the tables.

Phone class is used to create the PHONE table.

package com.vaannila.student;

 

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.Table;

 

@Entity

@Table(name = "PHONE")

public class Phone {

 

private long phoneId;

private String phoneType;

private String phoneNumber;

 

public Phone() {

}

 

public Phone(String phoneType, String phoneNumber) {

this.phoneType = phoneType;

this.phoneNumber = phoneNumber;

}

 

@Id

@GeneratedValue

@Column(name = "PHONE_ID")

public long getPhoneId() {

return this.phoneId;

}

 

public void setPhoneId(long phoneId) {

this.phoneId = phoneId;

}

 

@Column(name = "PHONE_TYPE", nullable = false, length=10)

public String getPhoneType() {

return this.phoneType;

}

 

public void setPhoneType(String phoneType) {

this.phoneType = phoneType;

}

 

@Column(name = "PHONE_NUMBER", nullable = false, length=15)

public String getPhoneNumber() {

return this.phoneNumber;

}

 

public void setPhoneNumber(String phoneNumber) {

this.phoneNumber = phoneNumber;

}

 

}

Now create the hibernate configuration file with the Student and Phone class mapping.

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE hibernate-configuration PUBLIC

"-//Hibernate/Hibernate Configuration DTD 3.0//EN"

"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>

<property name="hibernate.connection.driver_class"> org.hsqldb.jdbcDriver</property>

<property name="hibernate.connection.url"> jdbc:hsqldb:hsql://localhost<;/property>

<property name="hibernate.connection.username">sa</property>

<property name="connection.password"></property>

<property name="connection.pool_size">1</property>

<property name="hibernate.dialect"> org.hibernate.dialect.HSQLDialect</property>

<property name="show_sql">true</property>

<property name="hbm2ddl.auto">create-drop</property>

<mapping class="com.vaannila.student.Student" />

<mapping class="com.vaannila.student.Phone" />

</session-factory>

</hibernate-configuration>

Create the Main class to run the example.

package com.vaannila.student;

 

import java.util.HashSet;

import java.util.Set;

 

import org.hibernate.HibernateException;

import org.hibernate.Session;

import org.hibernate.Transaction;

 

import com.vaannila.util.HibernateUtil;

 

public class Main {

 

public static void main(String[] args) {

Session session = HibernateUtil.getSessionFactory().openSession();

Transaction transaction = null;

try {

transaction = session.beginTransaction();

 

Set<Phone> phoneNumbers = new HashSet<Phone>();

phoneNumbers.add(new Phone("house","32354353"));

phoneNumbers.add(new Phone("mobile","9889343423"));

 

Student student = new Student("Eswar", phoneNumbers);

session.save(student);

 

transaction.commit();

} catch (HibernateException e) {

transaction.rollback();

e.printStackTrace();

} finally {

session.close();

}

 

}

 

}