1. Database schema
...
2. Entity class:
import javax.persistence.*;
import java.sql.Date;
@Entity
@Table(name = "User")
public class User {
@Id
@GeneratedValue
private Long id;
@Column(name = "firstName")
private String firstName;
@Column(name = "surName")
private String surName;
@Column(name = "birthDate")
private Date birthDate;
@Column (name = "address")
private String emailAddress;
@OneToMany(cascade = {CascadeType.ALL})
@JoinColumn(name = "userId")
private Collection<Product> products;
public User() {
}
//getters and setters
}
import javax.persistence.*;
@Entity
@Table(name = "Product")
public class Product {
@Id
@GeneratedValue
private Long id;
@Column
private String name;
@Column
private String type;
@Column
private double price;
public Product() {
}
//getters and setters
}
3. Hibernate configuration file
Put annotated classes User.java and UserAdditionalInfo.java in to hibernate configuration file and mysql connection details:
<?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>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/test</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</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="hibernate.show_sql">true</property>
<property name="hbm2ddl.auto">create-drop</property>
<mapping class="net.hibernateApp.packt.maven.domain.User"/>
<mapping class="net.hibernateApp.packt.maven.domain.Product>"/>
</session-factory>
</hibernate-configuration>
4. Run
import net.hibernateApp.packt.maven.domain.User;
import net.hibernateApp.packt.maven.domain.Product;
import net.hibernateApp.packt.maven.hibernate.HibernateUtils;
import org.hibernate.SessionFactory;
import org.hibernate.Session;
public class Main {
public static void main(String[] args) {
User user = new User();
user.setFirstName("Christopher");
user.setSurName("Stepniak");
List<Product> products = new ArrayList<Product>();
products.add(new Product("axe", "weapon", 0.99));
products.add(new Product("sword", "weapon", 1.99));
products.add(new Product("apple", "food", 0.49));
user.setProducts(products);
user = saveUser(user);
List<Product> products1 = listProduct(user.getId());
System.out.println(products1.size());
}
private static User saveUser(User user){
SessionFactory sf;
sf = HibernateUtils.getSessionFactory();
Session session = sf.openSession();
session.beginTransaction();
Long id = (Long) session.save(user);
user.setId(id);
session.getTransaction().commit();
session.close();
return user;
}
private static List listProduct(Long userId) {
SessionFactory sf = HibernateUtils.getSessionFactory();
Session session = sf.openSession();
List objects = session.createQuery("from Product where userId= "+ userId).list();
session.close();
return objects;
}
}
Output: 3
Class net.hibernateApp.packt.maven.hibernate.HibernateUtils is described here:
Using
Hibernate persistence with Maven
