Knowledge Walls
J2EE Technologies Tutorial
Hyderabad, Andhra Pradesh, India
How to do One to Many mapping in JPA annotations using Spring Hibernate Framework
3704 Views
Hints 
@OneToMany is a one of the JPA annotation to specify a class object is mapped with current entity in the one to many manner. Current records is connected to many records of another table.

Example
@OneToMany
@JoinTable(name="STUDENT_ADDRESS",
                joinColumns=@JoinColumn(name="STUDENT_ID"),
                inverseJoinColumns=@JoinColumn(name="ADDRESS_ID"))
private Collection<Address> addresses = new ArrayList<Address>();
Output: SQL
create table Address
(addressId integer not null auto_increment,
city varchar(255),
state varchar(255),
studentInfo_STUDENT_ID integer,
primary key (addressId)) ENGINE=InnoDB;

create table STUDENT_ADDRESS
(STUDENT_ID integer not null,
ADDRESS_ID integer not null,
unique (ADDRESS_ID)) ENGINE=InnoDB;

create table STUDENT_INFO
(STUDENT_ID integer not null auto_increment,
STUDENT_NAME varchar(255),
primary key (STUDENT_ID)) ENGINE=InnoDB;

alter table Address
add index FK1ED033D4FA21989 (studentInfo_STUDENT_ID),
add constraint FK1ED033D4FA21989 foreign key (studentInfo_STUDENT_ID) references STUDENT_INFO (STUDENT_ID);

alter table STUDENT_ADDRESS
add index FK250691B08544B485 (ADDRESS_ID),
add constraint FK250691B08544B485 foreign key (ADDRESS_ID) references Address (addressId);

alter table STUDENT_ADDRESS
add index FK250691B0C4B1E0F3 (STUDENT_ID),
add constraint FK250691B0C4B1E0F3 foreign key (STUDENT_ID) references STUDENT_INFO (STUDENT_ID);
Output: Browser 
Project explorer preview 
Address.java
package com.knowledgewalls.entity;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToOne;

@Entity
public class Address {
    @Id @GeneratedValue(strategy=GenerationType.AUTO)
    private int addressId;
    private String city;
    private String state;
    
    @ManyToOne
    private StudentInfo studentInfo;
    
    public int getAddressId() {
        return addressId;
    }
    public void setAddressId(int addressId) {
        this.addressId = addressId;
    }
    
    public String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public String getState() {
        return state;
    }
    public void setState(String state) {
        this.state = state;
    }
    public StudentInfo getStudentInfo() {
        return studentInfo;
    }
    public void setStudentInfo(StudentInfo studentInfo) {
        this.studentInfo = studentInfo;
    }
}
StudentInfo.java
package com.knowledgewalls.entity;

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

import javax.persistence.Column;
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.OneToMany;
import javax.persistence.OneToOne;

@Entity(name="STUDENT_INFO")
public class StudentInfo {
    @Id @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="STUDENT_ID")
    private int studentId;
    
    @Column(name="STUDENT_NAME")
    private String StudentName;
    
    @OneToMany
    @JoinTable(name="STUDENT_ADDRESS",joinColumns=@JoinColumn(name="STUDENT_ID"),inverseJoinColumns=@JoinColumn(name="ADDRESS_ID"))
    private Collection<Address> addresses = new ArrayList<Address>();

    public int getStudentId() {
        return studentId;
    }
    public void setStudentId(int studentId) {
        this.studentId = studentId;
    }

    public String getStudentName() {
        return StudentName;
    }
    public void setStudentName(String studentName) {
        StudentName = studentName;
    }
    
    public Collection<Address> getAddresses() {
        return addresses;
    }
    public void setAddresses(Collection<Address> addresses) {
        this.addresses = addresses;
    }
}
StudentInfoDAO.java
package com.knowledgewalls.dao;

import java.util.Iterator;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import com.knowledgewalls.entity.Address;
import com.knowledgewalls.entity.StudentInfo;

@Repository
@Transactional
public class StudentInfoDAO {
    
    @PersistenceContext
    EntityManager em;
    
    public void save(StudentInfo userDetails){
        System.out.println("Called for; Student:"+userDetails.getStudentId());

        try {
            em.persist(userDetails);
            for (Iterator<Address> addressIterator = userDetails.getAddresses().iterator();addressIterator.hasNext();){
                Address address = addressIterator.next();
                em.persist(address);
            }
        }
        catch(Exception e){
            System.out.println("Insertion Failure; Student:"+userDetails.getStudentId());
            e.printStackTrace();
        }
    }
}
StudentInfoController.java
package com.knowledgewalls.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import com.knowledgewalls.dao.StudentInfoDAO;
import com.knowledgewalls.entity.Address;
import com.knowledgewalls.entity.StudentInfo;

@Controller
public class StudentInfoController {
    
    @Autowired
    StudentInfoDAO studentInfoDAO;
    
    @RequestMapping(value="/addStudent",method=RequestMethod.GET)
    public @ResponseBody String addUsers(){
        {
            StudentInfo studentInfo = new StudentInfo();
                studentInfo.setStudentName("Raj");
                
                Address addr = new Address();
                    addr.setCity("City 1");
                    addr.setState("State 1");
                    addr.setStudentInfo(studentInfo);
                    
                studentInfo.getAddresses().add(addr);
                
                Address addr2 = new Address();
                    addr2.setCity("City 2");
                    addr2.setState("State 2");
                    addr2.setStudentInfo(studentInfo);
                    
                studentInfo.getAddresses().add(addr2);
                    
            studentInfoDAO.save(studentInfo);
        }
        
        return "Inserted..";
        
    }
}
Persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd" >

  <persistence-unit name="hibernatePersistenceUnit">
          <properties>
            <property name="hibernate.hbm2ddl.auto" value="create" />
        </properties>
  </persistence-unit>

</persistence>
Beans-servlet.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd">

    <context:component-scan base-package="com.knowledgewalls" />
    <mvc:annotation-driven />
    <tx:annotation-driven transaction-manager="transactionManager" />
    
    <bean id="emf" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="persistenceXmlLocation" value="classpath*:persistence.xml" />
        <property name="persistenceUnitName" value="hibernatePersistenceUnit" />
        <property name="dataSource" ref="dataSource"/>
        <property name="jpaVendorAdapter" ref="jpaVendorAdapter"/>
    </bean>
    
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/test" />
        <property name="username" value="root" />
        <property name="password" value="mysql" />
        <property name="initialSize" value="5" />
        <property name="maxActive" value="10" />
    </bean>
    
    <bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
        <property name="database" value="MYSQL"></property>
        <property name="showSql" value="true"></property>
        <property name="generateDdl" value="false"></property>
        <property name="databasePlatform" value="org.hibernate.dialect.MySQL5InnoDBDialect"></property>
    </bean>
    
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
         <property name="entityManagerFactory" ref="emf" />
    </bean>
    
    <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" />
    <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/>
    <bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>

</beans>
Web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>Hibernate012_OneToManyNManyToOne</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
 
  <servlet>
    <servlet-name>beans</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>beans</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>
Best Lessons of "Hibernate 3.0 Examples"
Top lessons which are viewed more times.
  Copyright © 2014 Knowledge walls, All rights reserved
KnowledgeWalls
keep your tutorials and learnings with KnowledgeWalls. Don't lose your learnings hereafter. Save and revise it whenever required.
Click here for more details