How to Make a Project Using Spring Boot, MySQL, Spring Data JPA, and Maven?
For the sample project, below mentioned tools got used
- Java 8
- Eclipse IDE for development
- Hibernate ORM, Spring framework with Spring Data JPA
- MySQL database, MySQL Connector Java as JDBC driver.
Example Project Using Spring Boot, MySQL, Spring Data JPA, and Maven
Project Structure:
As this is getting prepared as a maven project, all dependencies are specified in pom.xml
pom.xml
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.gfg</ groupId > < artifactId >SpringDataJPAConsoleSample</ artifactId > < version >0.0.1-SNAPSHOT</ version > < properties > < maven.compiler.source >1.8</ maven.compiler.source > < maven.compiler.target >1.8</ maven.compiler.target > </ properties > < dependencies > <!-- Spring framework with support for Spring Data JPA --> < dependency > < groupId >org.springframework</ groupId > < artifactId >spring-context</ artifactId > < version >5.1.4.RELEASE</ version > </ dependency > < dependency > < groupId >org.springframework</ groupId > < artifactId >spring-orm</ artifactId > < version >5.1.4.RELEASE</ version > </ dependency > < dependency > < groupId >org.hibernate</ groupId > < artifactId >hibernate-core</ artifactId > < version >5.4.1.Final</ version > </ dependency > < dependency > < groupId >org.springframework.data</ groupId > < artifactId >spring-data-jpa</ artifactId > < version >2.1.4.RELEASE</ version > </ dependency > <!-- Spring framework with support for Spring Data JPA --> <!-- MySQL dependency --> < dependency > < groupId >mysql</ groupId > < artifactId >mysql-connector-java</ artifactId > < version >8.0.14</ version > </ dependency > </ dependencies > </ project > |
As we are connecting with MySQL, we need to create the database and table for use in the project
create database w3wiki; # Creation use w3wiki #Make the database active CREATE TABLE `Contest` ( `id` int(11) NOT NULL AUTO_INCREMENT, `contestName` varchar(45) NOT NULL, `contestDescription` varchar(45) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
Database connection properties are set in src/main/resources/persistence.xml
persistence.xml
XML
<? xml version = "1.0" encoding = "UTF-8" ?> < persistence xmlns = "http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd" version = "2.1" > <!-- Change the username and password with appropriate values --> < persistence-unit name = "BeginnerDB" > < properties > < property name = "javax.persistence.jdbc.url" value = "jdbc:mysql://localhost:3306/w3wiki?useSSL=false" /> < property name = "javax.persistence.jdbc.user" value = "***" /> < property name = "javax.persistence.jdbc.password" value = "***" /> < property name = "javax.persistence.jdbc.driver" value = "com.mysql.jdbc.Driver" /> < property name = "hibernate.show_sql" value = "true" /> < property name = "hibernate.format_sql" value = "true" /> </ properties > </ persistence-unit > </ persistence > |
Configuration of EntityManagerFactory and TransactionManager
ContestAppConfig.java
Java
import javax.persistence.EntityManagerFactory; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.data.jpa.repository.config.EnableJpaRepositories; import org.springframework.orm.jpa.JpaTransactionManager; import org.springframework.orm.jpa.LocalEntityManagerFactoryBean; @Configuration // Scan the repositories that is present under com.gfg.jpa @EnableJpaRepositories (basePackages = { "com.gfg.jpa" }) public class ContestAppConfig { @Bean // LocalEntityManagerFactoryBean sets up an EntityManagerFactory to work with BeginnerDB public LocalEntityManagerFactoryBean entityManagerFactory() { LocalEntityManagerFactoryBean factoryBean = new LocalEntityManagerFactoryBean(); factoryBean.setPersistenceUnitName( "BeginnerDB" ); return factoryBean; } @Bean // Transaction manager for the configured EntityManagerFactory, public JpaTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) { JpaTransactionManager transactionManager = new JpaTransactionManager(); transactionManager.setEntityManagerFactory(entityManagerFactory); return transactionManager; } } |
Let’s implement the model class.
Contest.java
Java
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; // It maps with db table Contest @Entity public class Contest { // The @Id and @GeneratedValue annotations map // the field id to the primary key column of the table. // Suppose that all the fields of the class have // same name as the column names in the database table. @Id @GeneratedValue (strategy = GenerationType.IDENTITY) private Long id; private String contestName; private String contestDescription; protected Contest() { } public Long getId() { return id; } public void setId(Long id) { this .id = id; } public String getContestName() { return contestName; } public void setContestName(String contestName) { this .contestName = contestName; } public String getContestDescription() { return contestDescription; } public void setContestDescription(String contestDescription) { this .contestDescription = contestDescription; } @Override public String toString() { return "Contest [contestName=" + contestName + ", contestDescription=" + contestDescription + "]" ; } } |
ContestRepository.java
Instead of writing a generic DAO class, a simple interface like below is enough. It extends CrudRepository defined by Spring Data JPA. Common CRUD operations like save(), findAll(), findById(), delete(), count() etc., are defined by the interface.
Java
import java.util.List; import org.springframework.data.repository.CrudRepository; public interface ContestRepository extends CrudRepository<Contest, Long> { // We can add the required methods here List<Contest> findByContestName(String contestName); } |
ContestService.java
Java
import java.util.List; import java.util.Optional; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; @Service ( "contestService" ) public class ContestService { @Autowired private ContestRepository contestRepository; public void test() { // Save a new contest Contest geekContest = new Contest(); geekContest.setContestName( "PremierLeague" ); geekContest.setContestDescription( "Inviting Beginner To submit articles in plenty" ); contestRepository.save(geekContest); // Find a contest by ID Optional<Contest> result = contestRepository.findById(1L); result.ifPresent(contest -> System.out.println(contest)); // Find contest by contest name List<Contest> contests = contestRepository.findByContestName( "PremierLeague" ); contests.forEach(contest -> System.out.println(contest)); // List all contests Iterable<Contest> iterator = contestRepository.findAll(); iterator.forEach(contest -> System.out.println(contest)); // Count number of contest long countOfContest = contestRepository.count(); System.out.println( "Number of contest held: " + countOfContest); } } |
We can test the same via a test file
ContestTest.java
Java
import org.springframework.context.annotation.AnnotationConfigApplicationContext; public class ContestTest { public static void main(String[] args) { AnnotationConfigApplicationContext appContext = new AnnotationConfigApplicationContext(); appContext.scan( "com.gfg.jpa" ); appContext.refresh(); ContestService contestService = (ContestService) appContext.getBean( "contestService" ); contestService.test(); appContext.close(); } } |
We can run the test file as an ordinary Java application
Output:
As we have tested via contestname as well, in the first output, we saw that one contest got inserted and the same is getting used to test while testing via contestname
We can check the DB data also
Note: id field is auto-generated.