Spring MVC is a popular model view controller framework that handles dependency injection at run time. Hibernate 5 is an ORM framework that acts as an abstraction over the database. It allows interaction with the underlying database by removing any implementation details which is handled by hibernate. In this article, we will integrate Spring MVC and Hibernate 5 with an in-memory database h2.
Requirements
- Maven
- IDE (Preferably IntelliJ)
- Java 8+
Required Dependencies
After creating an empty project you will need some core dependencies which are required for a bootstrap setup. In the dependencies section of your pom.xml add the following dependencies
spring-orm
The spring-orm module provides integration with hibernate
XML
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>5.2.3.RELEASE</version></dependency> |
hibernate-core
Core hibernate module for the hibernate dependencies
XML
<dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>5.4.2.Final</version></dependency> |
h2-database
In-memory database
XML
<dependency> <groupId>com.h2database</groupId> <artifactId>h2</artifactId> <version>1.4.197</version></dependency> |
commons-dbcp2
commons dependency for connection pooling
XML
<dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-dbcp2</artifactId> <version>2.7.0</version></dependency> |
lombok
helps generate boilerplate code for constructors/setters/getters etc
XML
<dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.24</version></dependency> |
Configuration
Hibernate requires certain configurations to bootstrap such as DB path, driver, username, password, etc. We are going to use the annotation-based configuration an XML-based configuration can also be used if needed.
Create a db.properties file:
db.properties file will contain the basic configurations of the database we will read this source to configure our hibernate session
# MySQL properties db.driver=org.h2.Driver db.url=jdbc:h2:mem:db;DB_CLOSE_DELAY=-1 db.username=sa db.password=sa # Hibernate properties hibernate.hbm2ddl.auto=create-drop hibernate.dialect=org.hibernate.dialect.H2Dialect
Configuring the Application
Create a configuration class to wire the details for hibernate and set up the session factory etc
Java
import org.apache.commons.dbcp2.BasicDataSource;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.PropertySource;import org.springframework.core.env.Environment;import org.springframework.orm.hibernate5.HibernateTransactionManager;import org.springframework.orm.hibernate5.LocalSessionFactoryBean;import org.springframework.transaction.PlatformTransactionManager;import org.springframework.transaction.annotation.EnableTransactionManagement; import javax.sql.DataSource;import java.util.Properties; @EnableTransactionManagement@Configuration@PropertySource("classpath:db.properties")public class ExampleConfiguration { @Autowired private Environment env; @Bean public LocalSessionFactoryBean sessionFactory() { LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean(); sessionFactory.setDataSource(dataSource()); sessionFactory.setPackagesToScan( new String[]{"com.example"}); sessionFactory.setHibernateProperties(hibernateProperties()); return sessionFactory; } @Bean public DataSource dataSource() { BasicDataSource dataSource = new BasicDataSource(); dataSource.setDriverClassName(env.getProperty("db.driver")); dataSource.setUrl(env.getProperty("db.url")); dataSource.setUsername(env.getProperty("db.username")); dataSource.setPassword(env.getProperty("db.password")); return dataSource; } @Bean public PlatformTransactionManager hibernateTransactionManager() { HibernateTransactionManager transactionManager = new HibernateTransactionManager(); transactionManager.setSessionFactory(sessionFactory().getObject()); return transactionManager; } private final Properties hibernateProperties() { Properties hibernateProperties = new Properties(); hibernateProperties.setProperty( "hibernate.hbm2ddl.auto", env.getProperty("hibernate.hbm2ddl.auto")); hibernateProperties.setProperty( "hibernate.dialect", env.getProperty("hibernate.dialect")); return hibernateProperties; }} |
Model class
model class for the entity/table
Java
package example.model; import lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor; import javax.persistence.*; @AllArgsConstructor@NoArgsConstructor@Data@Entity@Table(name = "user")public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "id") private int id; @Column(name = "first_name") private String firstName; @Column(name = "last_name") private String lastName;} |
Repository class
The persistence layer to persist the model in the database
Java
package example.repository; import example.model.User;import org.hibernate.SessionFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Repository; @Repositorypublic class UserRepository { @Autowired private SessionFactory sessionFactory; public void addUser(User user) { sessionFactory.getCurrentSession().save(user); } public User getUsers(int id) { return sessionFactory.getCurrentSession().get(User.class, id); }} |
Service class
service class to interact with the repository and persist items
Java
package example.service; import example.model.User;import example.repository.UserRepository;import lombok.RequiredArgsConstructor;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service; import javax.transaction.Transactional; @Service@RequiredArgsConstructorpublic class UserService { @Autowired private final UserRepository userRepository; @Transactional public void addUser(User user) { userRepository.addUser(user); } @Transactional public User getUser(int id) { return userRepository.getUsers(id); }} |
Application class
This is the entry point of the application, we need to wire this configuration to the application context.
Java
package example; import example.model.User;import example.service.UserService;import org.springframework.context.annotation.AnnotationConfigApplicationContext; public class ExampleApplication { public static void main(String[] args) { System.out.println("Starting application"); AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(ExampleConfiguration.class); UserService userService = context.getBean(UserService.class); // add user to the repo userService.addUser(new User(1, "john", "doe")); // search for the user in the repo User user = userService.getUser(1); System.out.println(user.toString()); }} |
Output:
Hibernate: drop table user if exists Hibernate: create table user (id integer generated by default as identity, first_name varchar(255), last_name varchar(255), primary key (id)) Oct 17, 2022 3:44:14 PM org.hibernate.engine.transaction.jta.platform.internal.JtaPlatformInitiator initiateService INFO: HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform] Hibernate: insert into user (id, first_name, last_name) values (null, ?, ?) Hibernate: select user0_.id as id1_0_0_, user0_.first_name as first_na2_0_0_, user0_.last_name as last_nam3_0_0_ from user user0_ where user0_.id=? User(id=1, firstName=john, lastName=doe)
Package Structure:
