Hibernate One To Many Annotation Example

Add following dependency in pom.xml file.

<dependencies>

<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.4.28.Final</version>
</dependency>

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>

</dependencies>
  

hibernate.cfg.xml

  <?xml version = "1.0" encoding = "utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>

<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/stds</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>

<property name="hbm2ddl.auto">update</property>
<property name="show_sql">true</property>
		
	
</session-factory>
</hibernate-configuration>
  

Student.java

package com.deepsingh44.model;

import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Entity
public class Student {
	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	private int roll;
	private String name;
	private float marks;
	@OneToMany(targetEntity = Certificate.class,
	cascade = CascadeType.ALL)
	private Set<Certificate> certificates;

	public Set<Certificate> getCertificates() {
		return certificates;
	}

	public void setCertificates(Set<Certificate> certificates) {
		this.certificates = certificates;
	}

	public int getRoll() {
		return roll;
	}

	public void setRoll(int roll) {
		this.roll = roll;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public float getMarks() {
		return marks;
	}

	public void setMarks(float marks) {
		this.marks = marks;
	}

}

  

Certificate.java

package com.deepsingh44.model;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
@Entity
public class Certificate {
	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	private int id;
	private String name;
	private String year;

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getYear() {
		return year;
	}

	public void setYear(String year) {
		this.year = year;
	}

}

Test.java

package com.deepsingh44.model;

import java.util.HashSet;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.Metadata;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;

public class Test {
public static void main(String[] args) {

// Load your configuration file
StandardServiceRegistry ssr = new StandardServiceRegistryBuilder().
		configure("hibernate.cfg.xml").
		build();
		Metadata meta = new MetadataSources(ssr).
		addAnnotatedClass(Student.class).
		addAnnotatedClass(Certificate.class)
		.getMetadataBuilder().
		build();

// Get sessionFactory object
SessionFactory factory = meta.getSessionFactoryBuilder().
		build();

// Get session object
Session session = factory.openSession();

// Compose Java Object
Student student = new Student();
student.setName("Sujeet1");
student.setMarks(87.8f);

Certificate c1=new Certificate();
c1.setName("Bca");
c1.setYear("2009");
Certificate c2=new Certificate();
c2.setName("Mca");
c2.setYear("2011");
		
		
HashSet<Certificate> cs=new HashSet();
cs.add(c1);
cs.add(c2);
		
student.setCertificates(cs);

// you need to persist java object in to database
session.persist(student);

// Actual transaction here
session.beginTransaction().commit();

session.close();
System.out.println("Successfully Inserted");

	}
}