Collections in Hibernate and Adding Keys Example

To overcome this problem we will use annotation @JoinTable.
 @JoinTable:
 Target:
Fields (including property get methods)

Used in the mapping of associations. It is specified on the owning side of an association.
A join table is typically used in the mapping of many-to-many and unidirectional one-to-many associations. It may also be used to map bidirectional many-to-one/one-to-many associations, unidirectional many-to-one relationships, and one-to-one associations (both bidirectional and unidirectional).

When a join table is used in mapping a relationship with an embeddable class on the owning side of the relationship, the containing entity rather than the embeddable class is considered the owner of the relationship.

If the JoinTable annotation is missing, the default values of the annotation elements apply. The name of the join table is assumed to be the table names of the associated primary tables concatenated together (owning side first) using an underscore.

@Entity
@Table (name=”USERS_DETAILS”)
public class UserDetails
{
@Id
@Column(name=”USER_ID”)
@GeneratedValue(strategy=GenerationType.AUTO)
private int    userId;

@Column(name=”USER_NAME”)
private String userName;@ElementCollection
@JoinTable(name=”USER_ADDRESS”,
joinColumns=@JoinColumn(name=”USER_ID”))
private Collection<Address> lisOfAddresses = new ArrayList<Address>();
}

package com.sdnext.hibernate.tutorial.dto;

import java.util.ArrayList;
import java.util.Collection;

import javax.persistence.Column;
import javax.persistence.ElementCollection;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.Table;

import org.hibernate.annotations.CollectionId;
import org.hibernate.annotations.GenericGenerator;
import org.hibernate.annotations.Type;

@Entity
@Table (name=”USER_DETAIL”)
public class UserDetails
{
@Id
    @Column(name=”USER_ID”)
    @GeneratedValue(strategy=GenerationType.AUTO)
private int    userId;

@Column(name=”USER_NAME”)
private String userName;

 @ElementCollection
@JoinTable(name=”USER_ADDRESS”,
joinColumns=@JoinColumn(name=”USER_ID”))
@GenericGenerator(strategy=”hilo”, name = “hilo-gen”)
@CollectionId(columns = { @Column(name=”ADDRESS_ID”) }, generator = “hilo-gen”, type = @Type(type=”long”))
private Collection<Address> lisOfAddresses = new ArrayList<Address>();

public Collection<Address> getLisOfAddresses() {
return lisOfAddresses;
}
public void setLisOfAddresses(Collection<Address> lisOfAddresses) {
this.lisOfAddresses = lisOfAddresses;
}
public int getUserId() {
return userId;
}
public void setUserId(int userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String toString()
{
return “[User Name: “+userName+”n Office Address: “+lisOfAddresses+”]”;
}
}

package com.sdnext.hibernate.tutorial;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;

import com.sdnext.hibernate.tutorial.dto.Address;
import com.sdnext.hibernate.tutorial.dto.UserDetails;

public class HibernateTestDemo {
/**
* @param args
*/
public static void main(String[] args)
{
UserDetails user = new UserDetails();
//user.setUserId(1);
user.setUserName(“Dinesh Rajput”);

Address address1 = new Address();
address1.setStreet(“First Street”);
address1.setCity(“First City”);
address1.setState(“First State”);
address1.setPincode(“First Pin”);

Address address2 = new Address();
address2.setStreet(“Second Street”);
address2.setCity(“Second City”);
address2.setState(“Second State”);
address2.setPincode(“Second Pin”);

user.getLisOfAddresses().add(address1);
user.getLisOfAddresses().add(address2);

SessionFactory sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(user);
session.getTransaction().commit();
session.close();
}
}

log4j:WARN No appenders could be found for logger (org.hibernate.cfg.annotations.Version).
log4j:WARN Please initialize the log4j system properly.
Hibernate: insert into USER_DETAIL (USER_NAME) values (?)
Hibernate: insert into USER_ADDRESS (USER_ID, ADDRESS_ID, CITY_NAME, PIN_CODE, STATE_NAME, STREET_NAME) values (?, ?, ?, ?, ?, ?)
Hibernate: insert into USER_ADDRESS (USER_ID, ADDRESS_ID, CITY_NAME, PIN_CODE, STATE_NAME, STREET_NAME) values (?, ?, ?, ?, ?, ?)