Spring Boot REST + JPA + Hibernate + MySQL Example

By Arvind Rai, March 17, 2017

This page will walk through spring boot REST + JPA + hibernate + MySQL example. Here we will create a REST application that will perform CRUD operation using MySQL. Spring boot provides default database configurations when it scans Spring Data JPA in classpath. Spring boot uses spring-boot-starter-data-jpa starter to configure spring JPA with hibernate. For data source we need to configure data source properties starting with spring.datasource.* in application.properties and spring boot JPA will configure data source automatically. Spring boot prefers tomcat pooling on first place then HikariCP and then Commons DBCP on the basis of availability. We need not to write spring configuration classes and just by configuring properties in application.properties we are done. In our DAO class we can get instance of EntityManager using dependency injection. To run the application we will create a class with main() method that will call SpringApplication.run() to start the application with embedded tomcat. The class with main() method will be annotated with @SpringBootApplication. In our application, at client side we will use RestTemplate to consume REST web service. Now find the complete example step by step.

Software Used
MySQL Database Schema
Project Structure in Eclipse
Maven File
Configure Properties in application.properties File
Create DAO for CRUD Operation
Create Service
Create Controller
Create Main Class using SpringApplication
Create Client using RestTemplate
Test Application
Reference
Download Source Code

Software Used

We are using following software in our example.
1. Java 8
2. Spring Boot 1.5.2.RELEASE
3. Maven 3.3
4. MySQL 5.5
5. Eclipse Mars

MySQL Database Schema

Find the database schema with seed data.
Database Schema

-- Dumping database structure for concretepage
CREATE DATABASE IF NOT EXISTS `concretepage`;
USE `concretepage`;
-- Dumping structure for table concretepage.articles
CREATE TABLE IF NOT EXISTS `articles` (
  `article_id` int(5) NOT NULL AUTO_INCREMENT,
  `title` varchar(200) NOT NULL,
  `category` varchar(100) NOT NULL,
  PRIMARY KEY (`article_id`)
) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=latin1;
-- Dumping data for table concretepage.articles: ~3 rows (approximately)
INSERT INTO `articles` (`article_id`, `title`, `category`) VALUES
	(1, 'Java Concurrency', 'Java'),
	(2, 'Hibernate HQL ', 'Hibernate'),
	(3, 'Spring MVC with Hibernate', 'Spring');

Find the JPA entity for the given table.
Article.java

package com.concretepage.entity;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name="articles")
public class Article implements Serializable { 
	private static final long serialVersionUID = 1L;
	@Id
	@GeneratedValue(strategy=GenerationType.AUTO)
	@Column(name="article_id")
        private int articleId;  
	@Column(name="title")
        private String title;
	@Column(name="category")	
	private String category;
	public int getArticleId() {
		return articleId;
	}
	public void setArticleId(int articleId) {
		this.articleId = articleId;
	}
	public String getTitle() {
		return title;
	}
	public void setTitle(String title) {
		this.title = title;
	}
	public String getCategory() {
		return category;
	}
	public void setCategory(String category) {
		this.category = category;
	}
}

Project Structure in Eclipse

Find the project structure in eclipse.

Spring Boot REST + JPA + Hibernate + MySQL Example

Maven File

Find the maven file used in our example.
pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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.concretepage</groupId>
	<artifactId>spring-boot-demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>
	<name>spring-demo</name>
	<description>Spring Boot Demo Project</description>
	<parent>
	   <groupId>org.springframework.boot</groupId>
	   <artifactId>spring-boot-starter-parent</artifactId>
	   <version>1.5.2.RELEASE</version>
	</parent>
	<properties>
	   <java.version>1.8</java.version>
	</properties>
	<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>mysql</groupId>
		    <artifactId>mysql-connector-java</artifactId>
	    </dependency>	 
    	    <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-devtools</artifactId>
                    <optional>true</optional>
            </dependency> 
	</dependencies> 
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
</project>

Find the description of spring boot starter configured in maven file.
spring-boot-starter-parent : Parent POM for dependency management.
spring-boot-starter-web: Starter for building web, REST applications. It uses tomcat server as default embedded server.
spring-boot-starter-data-jpa: Starter for spring data JPA with hibernate.
spring-boot-devtools : It provides developer tools. These tools are helpful in application development mode. One of the features of developer tool is automatic restart of the server for any change in code.
spring-boot-maven-plugin : It is used to create executable JAR of the application.

Configure Properties in application.properties File

The properties related to database, hibernate and logging need to be configured in application.properties file. These properties will automatically be read by Spring boot.
application.properties

#spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/concretepage
spring.datasource.username=root
spring.datasource.password=
spring.datasource.tomcat.max-wait=20000
spring.datasource.tomcat.max-active=50
spring.datasource.tomcat.max-idle=20
spring.datasource.tomcat.min-idle=15

spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQLDialect
spring.jpa.properties.hibernate.id.new_generator_mappings = false
spring.jpa.properties.hibernate.format_sql = true

logging.level.org.hibernate.SQL=DEBUG
logging.level.org.hibernate.type.descriptor.sql.BasicBinder=TRACE

The data source properties starting with spring.datasource.* will automatically be read by Spring boot JPA. To change the Hibernate properties we will use prefix spring.jpa.properties.* with Hibernate property name. On the basis of given data source URL, Spring boot can automatically identify data source driver class. So we need not to configure diver class.
Find the properties to configure JpaBaseConfiguration and HibernateJpaAutoConfiguration in application.properties.
spring.data.jpa.repositories.enabled: It enables JPA repositories. The default value is true.
spring.jpa.database: It targets database to operate on. By default embedded database is auto-detected.
spring.jpa.database-platform: It is used to provide the name of database to operate on. By default it is auto- detected.
spring.jpa.generate-ddl: It is used to initialize schema on startup. By default the value is false.
spring.jpa.hibernate.ddl-auto: It is DDL mode used for embedded database. Default value is create-drop.
spring.jpa.hibernate.naming.implicit-strategy: It is Hibernate 5 implicit naming strategy fully qualified name.
spring.jpa.hibernate.naming.physical-strategy: It is Hibernate 5 physical naming strategy fully qualified name.
spring.jpa.hibernate.use-new-id-generator-mappings: It is used for Hibernate IdentifierGenerator for AUTO, TABLE and SEQUENCE.
spring.jpa.open-in-view: The default value is true. It binds a JPA EntityManager to the thread for the entire processing of the request.
spring.jpa.properties.*: It sets additional native properties to set on the JPA provider.
spring.jpa.show-sql: It enables logging of SQL statements. Default value is false.

Create DAO for CRUD Operation

Find the DAO used in example to perform CRUD operation. To inject the instance of EntityManager we will use @PersistenceContext.
IArticleDAO.java

package com.concretepage.dao;
import java.util.List;
import com.concretepage.entity.Article;
public interface IArticleDAO {
    List<Article> getAllArticles();
    Article getArticleById(int articleId);
    void addArticle(Article article);
    void updateArticle(Article article);
    void deleteArticle(int articleId);
    boolean articleExists(String title, String category);
}

ArticleDAO.java

package com.concretepage.dao;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
import com.concretepage.entity.Article;
@Transactional
@Repository
public class ArticleDAO implements IArticleDAO {
	@PersistenceContext	
	private EntityManager entityManager;	
	@Override
	public Article getArticleById(int articleId) {
		return entityManager.find(Article.class, articleId);
	}
	@SuppressWarnings("unchecked")
	@Override
	public List<Article> getAllArticles() {
		String hql = "FROM Article as atcl ORDER BY atcl.articleId";
		return (List<Article>) entityManager.createQuery(hql).getResultList();
	}	
	@Override
	public void addArticle(Article article) {
		entityManager.persist(article);
	}
	@Override
	public void updateArticle(Article article) {
		Article artcl = getArticleById(article.getArticleId());
		artcl.setTitle(article.getTitle());
		artcl.setCategory(article.getCategory());
		entityManager.flush();
	}
	@Override
	public void deleteArticle(int articleId) {
		entityManager.remove(getArticleById(articleId));
	}
	@Override
	public boolean articleExists(String title, String category) {
		String hql = "FROM Article as atcl WHERE atcl.title = ? and atcl.category = ?";
		int count = entityManager.createQuery(hql).setParameter(1, title)
		              .setParameter(2, category).getResultList().size();
		return count > 0 ? true : false;
	}
}

Create Service

Find the service class used in our example.
IArticleService.java

package com.concretepage.service;
import java.util.List;
import com.concretepage.entity.Article;
public interface IArticleService {
     List<Article> getAllArticles();
     Article getArticleById(int articleId);
     boolean addArticle(Article article);
     void updateArticle(Article article);
     void deleteArticle(int articleId);
}

ArticleService.java

package com.concretepage.service;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.concretepage.dao.IArticleDAO;
import com.concretepage.entity.Article;
@Service
public class ArticleService implements IArticleService {
	@Autowired
	private IArticleDAO articleDAO;
	@Override
	public Article getArticleById(int articleId) {
		Article obj = articleDAO.getArticleById(articleId);
		return obj;
	}	
	@Override
	public List<Article> getAllArticles(){
		return articleDAO.getAllArticles();
	}
	@Override
	public synchronized boolean addArticle(Article article){
                if (articleDAO.articleExists(article.getTitle(), article.getCategory())) {
    	            return false;
                } else {
    	            articleDAO.addArticle(article);
    	            return true;
                }
	}
	@Override
	public void updateArticle(Article article) {
		articleDAO.updateArticle(article);
	}
	@Override
	public void deleteArticle(int articleId) {
		articleDAO.deleteArticle(articleId);
	}
}

Create Controller

Find the controller class that will expose web service methods.
ArticleController.java

package com.concretepage.controller;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.util.UriComponentsBuilder;
import com.concretepage.entity.Article;
import com.concretepage.service.IArticleService;
@Controller
@RequestMapping("user")
public class ArticleController {
	@Autowired
	private IArticleService articleService;
	@GetMapping("article/{id}")
	public ResponseEntity<Article> getArticleById(@PathVariable("id") Integer id) {
		Article article = articleService.getArticleById(id);
		return new ResponseEntity<Article>(article, HttpStatus.OK);
	}
	@GetMapping("articles")
	public ResponseEntity<List<Article>> getAllArticles() {
		List<Article> list = articleService.getAllArticles();
		return new ResponseEntity<List<Article>>(list, HttpStatus.OK);
	}
	@PostMapping("article")
	public ResponseEntity<Void> addArticle(@RequestBody Article article, UriComponentsBuilder builder) {
                boolean flag = articleService.addArticle(article);
                if (flag == false) {
        	    return new ResponseEntity<Void>(HttpStatus.CONFLICT);
                }
                HttpHeaders headers = new HttpHeaders();
                headers.setLocation(builder.path("/article/{id}").buildAndExpand(article.getArticleId()).toUri());
                return new ResponseEntity<Void>(headers, HttpStatus.CREATED);
	}
	@PutMapping("article")
	public ResponseEntity<Article> updateArticle(@RequestBody Article article) {
		articleService.updateArticle(article);
		return new ResponseEntity<Article>(article, HttpStatus.OK);
	}
	@DeleteMapping("article/{id}")
	public ResponseEntity<Void> deleteArticle(@PathVariable("id") Integer id) {
		articleService.deleteArticle(id);
		return new ResponseEntity<Void>(HttpStatus.NO_CONTENT);
	}	
}

We have created following URLS for CRUD operation.
1. Create :
HTTP Method: POST, URL: /user/article

2. Read :
HTTP Method: GET, URL: /user/article/{id}
HTTP Method: GET, URL: /user/articles

3. Update :
HTTP Method: PUT, URL: /user/article

4. Delete :
HTTP Method: DELETE, URL: /user/article/{id}

Create Main Class using SpringApplication

Create a class with main() method that will call SpringApplication.run() to run the application. First all JAR dependencies are downloaded and then the project is compiled and then embedded tomcat server is started.
MyApplication.java

package com.concretepage;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class MyApplication {  
	public static void main(String[] args) {
		SpringApplication.run(MyApplication.class, args);
        }       
}

We need to annotate this class with @SpringBootApplication annotation that is equivalent to @Configuration, @EnableAutoConfiguration and @ComponentScan annotations.

Create Client using RestTemplate

Find the client that will consume REST web services. We are using RestTemplate to communicate with REST web service server.
RestClientUtil.java

package com.concretepage.client;
import java.net.URI;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.client.RestTemplate;
import com.concretepage.entity.Article;
public class RestClientUtil {
    public void getArticleByIdDemo() {
    	HttpHeaders headers = new HttpHeaders();
    	headers.setContentType(MediaType.APPLICATION_JSON);
        RestTemplate restTemplate = new RestTemplate();
	String url = "http://localhost:8080/user/article/{id}";
        HttpEntity<String> requestEntity = new HttpEntity<String>(headers);
        ResponseEntity<Article> responseEntity = restTemplate.exchange(url, HttpMethod.GET, requestEntity, Article.class, 1);
        Article article = responseEntity.getBody();
        System.out.println("Id:"+article.getArticleId()+", Title:"+article.getTitle()
                 +", Category:"+article.getCategory());      
    }
    public void getAllArticlesDemo() {
	HttpHeaders headers = new HttpHeaders();
	headers.setContentType(MediaType.APPLICATION_JSON);
        RestTemplate restTemplate = new RestTemplate();
	String url = "http://localhost:8080/user/articles";
        HttpEntity<String> requestEntity = new HttpEntity<String>(headers);
        ResponseEntity<Article[]> responseEntity = restTemplate.exchange(url, HttpMethod.GET, requestEntity, Article[].class);
        Article[] articles = responseEntity.getBody();
        for(Article article : articles) {
              System.out.println("Id:"+article.getArticleId()+", Title:"+article.getTitle()
                      +", Category: "+article.getCategory());
        }
    }
    public void addArticleDemo() {
    	HttpHeaders headers = new HttpHeaders();
    	headers.setContentType(MediaType.APPLICATION_JSON);
        RestTemplate restTemplate = new RestTemplate();
	String url = "http://localhost:8080/user/article";
	Article objArticle = new Article();
	objArticle.setTitle("Spring REST Security using Hibernate");
	objArticle.setCategory("Spring");
        HttpEntity<Article> requestEntity = new HttpEntity<Article>(objArticle, headers);
        URI uri = restTemplate.postForLocation(url, requestEntity);
        System.out.println(uri.getPath());    	
    }
    public void updateArticleDemo() {
    	HttpHeaders headers = new HttpHeaders();
    	headers.setContentType(MediaType.APPLICATION_JSON);
        RestTemplate restTemplate = new RestTemplate();
        String url = "http://localhost:8080/user/article";
	Article objArticle = new Article();
	objArticle.setArticleId(1);
	objArticle.setTitle("Update:Java Concurrency");
	objArticle.setCategory("Java");
        HttpEntity<Article> requestEntity = new HttpEntity<Article>(objArticle, headers);
        restTemplate.put(url, requestEntity);
    }
    public void deleteArticleDemo() {
    	HttpHeaders headers = new HttpHeaders();
    	headers.setContentType(MediaType.APPLICATION_JSON);
        RestTemplate restTemplate = new RestTemplate();
	String url = "http://localhost:8080/user/article/{id}";
        HttpEntity<Article> requestEntity = new HttpEntity<Article>(headers);
        restTemplate.exchange(url, HttpMethod.DELETE, requestEntity, Void.class, 4);        
    }
    public static void main(String args[]) {
    	RestClientUtil util = new RestClientUtil();
        //util.getArticleByIdDemo();
    	util.getAllArticlesDemo();
    	//util.addArticleDemo();
    	//util.updateArticleDemo();
    	//util.deleteArticleDemo();
    }    
}

Test Application

To test the application, first create table in MySQL as given in the example. Then we can run REST web service in following ways.
1. Using Eclipse: Download the project source code using the download link given at the end of page. Import the project into eclipse. Using command prompt, go to the root folder of the project and run.

mvn clean eclipse:eclipse

and then refresh the project in eclipse. Run Main class MyApplication by clicking Run as -> Java Application. Tomcat server will be started.

2. Using Maven Command: Download the project source code. Go to the root folder of the project using command prompt and run the command.

mvn spring-boot:run

Tomcat server will be started.

3. Using Executable JAR: Using command prompt, go to the root folder of the project and run the command.

mvn clean package

We will get executable JAR spring-boot-demo-0.0.1-SNAPSHOT.jar in target folder. Run this JAR as

java -jar target/spring-boot-demo-0.0.1-SNAPSHOT.jar

Tomcat server will be started.

Now we are ready to test the application. To run client, go to the RestClientUtil class in eclipse and click on Run as -> Java Application.
We can also test application using Postman. Find the print screen.