One to One Bidirectional Mapping Example In Hibernate/JPA Using Spring Boot and Oracle

By
Rakesh
-

In this post, we will see One to One Bidirectional Mapping Example In Hibernate/JPA Using Spring Boot and Oracle.

  • We have two entity Book.java and Story .java. Book and Story entity have one to one bidirectional relationship that means the Book entity has a Story entity and the Story entity also contains Book entity.
  • We will not create a table, let’s hibernate do this job.
  • After running this example we will be able to save Book as well Story in oracle database using postman.

Note –  Default Fetch type in case of  below annotations.

@OneToOne – Default fetch type is EAGER.
@OneToMany – Default fetch type is LAZY.
@ManyToOne – Default fetch type is EAGER.
@ManyToMany – Default fetch type is LAZY.

 

One to One Bidirectional Mapping In Hibernate/JPA Spring Boot

 

After running the below example we will have database entry like below.

Let’s see a complete example of One to One Bidirectional Mapping In Hibernate/JPA Spring Boot from scratch.

Prerequisites –

  • JDK 1.8
  • Oracle 10g
  • Eclipse
  • maven
  • postman

 

Open eclipse and create maven project, Don’t forget to check ‘Create a simple project (skip)’click on next. Fill all details(GroupId – onetoonehibernatejpa, ArtifactId – onetoonehibernatejpa and name – onetoonehibernatejpa) and click on finish. Keep packaging as the jar.

Replace the pom.xml with the below code.

<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>onetoonehibernatejpa</groupId>
	<artifactId>onetoonehibernatejpa</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>onetoonehibernatejpa</name>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.2.RELEASE</version>
	</parent>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>

		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-jpa</artifactId>
		</dependency>

		<dependency>
			<groupId>com.oracle</groupId>
			<artifactId>ojdbc6</artifactId>
			<version>11.2.0.3</version>
		</dependency>

	</dependencies>

	<build>
		<finalName>${project.artifactId}</finalName>
		<plugins>

			<plugin>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.1</version>
				<configuration>
					<fork>true</fork>
					<executable>C:\Program Files\Java\jdk1.8.0_131\bin\javac.exe</executable>
				</configuration>
			</plugin>


		</plugins>
	</build>
</project>

Note – In pom.xml we have defined javac.exe path in configuration tag. You need to change accordingly i.e where you have installed JDK.

If you see any error for oracle dependency then follow these steps.

Let maven download all necessary jar. Once it is done we will able to see the maven dependency folder which contains different jar files.

We are good now. We can start writing our controller classes, ServiceImpl and Repository. The directory structure of the application looks as below.

One to One Bidirectional Mapping In Hibernate/JPA Spring Boot

 

Define entity class i.e Book.java and Story.java.

Book.java

package com.onetoonehibernatejpa.entity;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;

import com.fasterxml.jackson.annotation.JsonManagedReference;

@Entity
public class Book {

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	private int bookId;

	@Column(name = "book_name")
	private String bookName;

	@OneToOne(cascade = CascadeType.ALL, mappedBy = "book")
	@JsonManagedReference
	private Story story;

	public Story getStory() {
		return story;
	}

	public void setStory(Story story) {
		this.story = story;
	}

	public int getBookId() {
		return bookId;
	}

	public void setBookId(int bookId) {
		this.bookId = bookId;
	}

	public String getBookName() {
		return bookName;
	}

	public void setBookName(String bookName) {
		this.bookName = bookName;
	}

}

Story.java

package com.onetoonehibernatejpa.entity;

import javax.persistence.CascadeType;
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.OneToOne;

import com.fasterxml.jackson.annotation.JsonBackReference;

@Entity
public class Story {

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	private int storyId;

	@Column(name = "story_name")
	private String storyName;

	@OneToOne(cascade = CascadeType.ALL)
	@JoinColumn(name = "book_id")
	@JsonBackReference
	private Book book;

	public int getStoryId() {
		return storyId;
	}

	public void setStoryId(int storyId) {
		this.storyId = storyId;
	}

	public String getStoryName() {
		return storyName;
	}

	public void setStoryName(String storyName) {
		this.storyName = storyName;
	}

	public Book getBook() {
		return book;
	}

	public void setBook(Book book) {
		this.book = book;
	}

}

 

Define the repository interface extending CrudRepository.

BookRepository.java

package com.onetoonehibernatejpa.repository;

import java.io.Serializable;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

import com.onetoonehibernatejpa.entity.Book;
@Repository
public interface BookRepository extends CrudRepository<Book,Serializable> {
	public Book findByBookId(int bookId);
}

Define service interface i.e BookService.java for One to One Bidirectional In Hibernate/JPA Spring Boot example

package com.onetoonehibernatejpa.service;

import org.springframework.stereotype.Component;

import com.onetoonehibernatejpa.entity.Book;

@Component
public interface BookService {
	public Book saveBook(Book book);
	public Book findByBookId(int bookId);
}

Define service implementation class.

BookServiceImpl.java

package com.onetoonehibernatejpa.impl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.onetoonehibernatejpa.entity.Book;
import com.onetoonehibernatejpa.entity.Story;
import com.onetoonehibernatejpa.repository.BookRepository;
import com.onetoonehibernatejpa.service.BookService;

@Service("bookServiceImpl")
public class BookServiceImpl implements BookService {

	@Autowired
	private BookRepository bookRepository;

	public Book saveBook(Book book) {

		Story story = book.getStory();
		story.setBook(book);
		book = bookRepository.save(book);
		return book;

	}

	public Book findByBookId(int bookId) {
		Book book = bookRepository.findByBookId(bookId);
		return book;
	}
}

Note – See here more about @Component, @Controller, @Service and @Repository annotations here.

Define the controller class or endpoint.

BookController.java

package com.onetoonehibernatejpa.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import com.onetoonehibernatejpa.entity.Book;
import com.onetoonehibernatejpa.service.BookService;
 
@RestController
@RequestMapping(value = "/book")
public class BookController {
	
	@Autowired
	private BookService bookService;
	
	
	@RequestMapping(value = "/savebook",method = RequestMethod.POST)
	@ResponseBody
    public Book saveBook(@RequestBody Book book) {
		Book bookResponse = bookService.saveBook(book);
		return bookResponse;
	}
	
	@RequestMapping(value = "/{bookId}",method = RequestMethod.GET)
    @ResponseBody
    public Book getBookDetails(@PathVariable int bookId) {
		Book bookResponse = bookService.findByBookId(bookId);
		
		return bookResponse;
	}
	
	
}

Note – See more details about @Controller and RestController here.

Define the JpaConfig.java

package com.onetoonehibernatejpa.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@Configuration
@EnableJpaRepositories(basePackages = "com.onetoonehibernatejpa.repository")
public class JpaConfig {

}

Note – See more details about @Configuration annotations here.

Define the SpringMain.java

package com.onetoonehibernatejpa.main;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@ComponentScan(basePackages="com.onetoonehibernatejpa.*")
@EntityScan("com.onetoonehibernatejpa.*")
public class SpringMain {
	public static void main(String[] args) {

        SpringApplication.run(SpringMain.class, args);
    }

}

Note – See more details about @ComponentScan here.

And finally, we have an application.properties file where we have database details.

application.properties

# Connection url for the database
spring.datasource.url=jdbc:oracle:thin:@localhost:1521:XE
spring.datasource.username=SYSTEM
spring.datasource.password=oracle2
spring.datasource.driver-class-name=oracle.jdbc.driver.OracleDriver
# Show or not log for each sql query
spring.jpa.show-sql = true
 
 
spring.jpa.hibernate.ddl-auto =update
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.Oracle10gDialect
 
server.port = 9091

We are almost done. Just build the project once running the main method. Open git bash or cmd and Run mvn clean install.

Let’s deploy the application running SpringMain class as a java application.

Now we will prepare json data and will try save in database.

Sample request JSON data-

{
"bookName":"rich dad poor dad",
 "story":{
   "storyName":"motivational story"
 }
}

 

Let’s test the save url.

One to One Bidirectional In Hibernate/JPA Spring Boot

Let’s check the database. One to One Bidirectional In Hibernate/JPA Spring Boot.

One to One Bidirectional In Hibernate/JPA Spring Boot

Yes, we have record in the book as well as story table. Did you notice book_id is the column in the story table is a foreign key? This is the primary key for the book table.

 

Now test the get URL i.e http://localhost:9091/book/1

 

Let’s see in the below diagram which will give us a brief about flow.

That’s all about One to One Bidirectional In Hibernate/JPA Spring Boot. If you feel any problem to run the application leave a comment.

Other association mapping example in hibernate using Spring Boot and oracle.

One to One Mapping Annotation Example in Hibernate/JPA using Spring Boot and Oracle.
One To Many Mapping Annotation Example In Hibernate/JPA Using Spring Boot And Oracle.
One To Many Bidirectional Mapping In Hibernate/JPA Annotation Example Using Spring Boot and Oracle
Many To One Unidirectional Mapping In Hibernate/JPA Annotation Example Using Spring Boot and Oracle.
Many To Many Mapping Annotation Example In Hibernate/JPA Using Spring Boot And Oracle.

 

Inheritance Mapping in Hibernate Using Spring Boot and Oracle.

Spring Data JPA tutorials.

@OneToOne docs.

Summary – We have seen One to One Bidirectional Mapping in Hibernate/JPA using Spring Boot and Oracle. In one to one mapping one entity associated with another entity Bidirectionally.

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