Hibernate One to Many Example using Annotation

 Hibernate One to Many Example using Annotation

Directory Structure:

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

<modelVersion>4.0.0</modelVersion>

<groupId>com.test</groupId>

<artifactId>TimeStamp</artifactId>

<version>0.0.1-SNAPSHOT</version>

<packaging>jar</packaging>

<name>TimeStamp</name>

<url>http://maven.apache.org</url>

<properties>

<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

<maven.compiler.source>1.9</maven.compiler.source>

<maven.compiler.target>1.9</maven.compiler.target>

</properties>

<dependencies>

<dependency>

<groupId>junit</groupId>

<artifactId>junit</artifactId>

<version>3.8.1</version>

<scope>test</scope>

</dependency>

<!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->

<dependency>

<groupId>org.hibernate</groupId>

<artifactId>hibernate-core</artifactId>

<version>5.6.8.Final</version>

</dependency>

<!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->

<dependency>

<groupId>org.projectlombok</groupId>

<artifactId>lombok</artifactId>

<version>1.18.20</version>

<scope>provided</scope>

</dependency>

<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->

<dependency>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

<version>8.0.22</version>

</dependency>

</dependencies>

</project>

Entity

Address 

package com.test.entity;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.Id;

import javax.persistence.Table;

import lombok.AllArgsConstructor;

import lombok.Data;

import lombok.NoArgsConstructor;

import lombok.ToString;

@Data

@AllArgsConstructor

@NoArgsConstructor

@ToString

@Entity

@Table(name = "addrtab")

public class Address {

@Id

@Column(name="aid")

private int addrId;

private String loc;

private String pin;

}

Employee

package com.test.entity;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.Id;

import javax.persistence.JoinColumn;

import javax.persistence.ManyToOne;

import javax.persistence.Table;

import lombok.AllArgsConstructor;

import lombok.Data;

import lombok.NoArgsConstructor;

import lombok.ToString;

@Data

@AllArgsConstructor

@NoArgsConstructor

@ToString

@Entity

@Table(name = "emptab")

public class Employee {

@Id

@Column(name = "eid")

private int empId;

@Column(name = "ename")

private String empName;

@Column(name = "esal")

private double empSal;

@ManyToOne

@JoinColumn(name = "adiFk")//fk column

private Address addr;

}

HibernateUtil

package com.test.util;

import java.util.Properties;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.Configuration;

import org.hibernate.cfg.Environment;

import com.test.entity.Address;

import com.test.entity.Employee;

public class HibernateUtil {

static SessionFactory factory = null;

static {

Configuration cfg = new Configuration();

Properties props = new Properties();

props.put(Environment.URL, "jdbc:mysql://localhost:3306/new");

props.put(Environment.USER, "root");

props.put(Environment.PASS, "root");

props.put(Environment.SHOW_SQL, true);

props.put(Environment.FORMAT_SQL, true);

props.put(Environment.HBM2DDL_AUTO, "update");

cfg.setProperties(props);

cfg.addAnnotatedClass(Employee.class);

cfg.addAnnotatedClass(Address.class);

factory = cfg.buildSessionFactory();

}

public static SessionFactory getSessionFactory() {

return factory;

}

public static Session getSession() {

return factory.openSession();

}

}

Test

package com.test;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import com.test.entity.Address;

import com.test.entity.Employee;

import com.test.util.HibernateUtil;

public class Test {

public static void main(String[] args) {

Transaction tx = null;

//get the SessionFactory 

SessionFactory factory = HibernateUtil.getSessionFactory();

//get the Session

Session ses = HibernateUtil.getSession();

try(factory;ses){

//begin the tx

tx = ses.beginTransaction();

Address addr = new Address();

addr.setAddrId(101);

addr.setLoc("pune");

addr.setPin("431605");

//emp objects

Employee e1 = new Employee();

e1.setEmpId(1);

e1.setEmpName("Sam");

e1.setEmpSal(4000.0);

e1.setAddr(addr);

Employee e2 = new Employee();

e2.setEmpId(2);

e2.setEmpName("Jhon");

e2.setEmpSal(5000.0);

e2.setAddr(addr);

Employee e3 = new Employee();

e3.setEmpId(3);

e3.setEmpName("Brock");

e3.setEmpSal(6000.0);

e3.setAddr(addr);

ses.save(addr);

ses.save(e1);

ses.save(e2);

ses.save(e3);

//commit the tx

tx.commit();

}catch(Exception e) {

e.printStackTrace();

}

}

}

database tables

emptab

addrtab