Hibernate One to Many Example using Annotation

Create the Maven project add mysql , hibernate , lombok dependencies as belows in pom.xml

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>

Address.java

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.java


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.java

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();
        }
    }
}

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Hibernate One to Many Example using Annotation

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