Abstract

This project is a sample of a Spring/Hibernate project with Annotations configuration. It is aimed to compare Spring/Hibernate configuration with another project, xml-driven, in parallel.

Project structure

Project
 |  src
 |   |-main
 |   |   |-java
 |   |   |   |-com
 |   |   |       |-dohbedoh
 |   |   |           |-SpringHibernateAnnotations.java
 |   |   |           |-SpringHibernateAnnotationsConfig.java
 |   |   |           |-config
 |   |   |               |-DataSourceConfig.java
 |   |   |               |-HibernateConfig.java
 |   |   |           |-dao
 |   |   |               |-AbstractDAO.java
 |   |   |               |-CompanyDAO.java
 |   |   |               |-impl
 |   |   |                   |-CompanyDAOImpl.java
 |   |   |           |-model
 |   |   |               |-Company.java
 |   |   |           |-service
 |   |   |               |-CompanyService.java
 |   |   |-resources
 |   |       |-logback.xml
 |   |       |-database
 |   |       |   |-bootstrap.sql
 |   |       |   |-database.properties
 |   |       |   |-hibernate.properties
 |   |-test
 |   |   |-java
 |   |   |   |-com
 |   |   |       |-dohbedoh
 |   |   |           |-dao
 |   |   |  			 |-CompanyDAOTest.java
 |   |   |           |-service
 |   |   |  			 |-CompanyServiceTest.java
 |   |   |-resources
 |   |       |-logback-test.xml
 pom.xml

Spring

The configuration is divided in separate configuration classes:

• Data Source in com.dohbedoh.config.DataSourceConfig.java
• Hibernate and Transaction Manager in com.dohbedoh.config.HibernateConfig.java
• General configuration and Components scan in com.dohbedoh.SpringHibernateAnnotationConfig.java

####Project Spring Structure

Project
 |  src
 |   |-main
 |   |   |-java
 |   |   |   |-com
 |   |   |       |-dohbedoh
 |   |   |           |-SpringHibernateAnnotationsConfig.java
 |   |   |           |-config
 |   |   |               |-DataSourceConfig.java
 |   |   |               |-HibernateConfig.java

SpringHibernateAnnotationConfig.java is the entry point and set up the @ComponentScan and @EnableTransactionManagement (similar to the tx:annotation-driven/) for our application. We also create a PropertySourcesPlaceholderConfigurer to be able to inject properties values using @Value annotation in our configuration classes.

There are different to access the properties. Both are demonstrated in this project. Our Data Source configuration is using a PropertySourcePlaceHolderConfigurer while Hibernate configuration is using the Environment Spring object. Spring recommend the use of the latter.

####SpringHibernateAnnotationConfig.java

...

@Configuration
@EnableTransactionManagement
@ComponentScan
public class SpringHibernateAnnotationsConfig {
       
    @Bean
    public PropertySourcesPlaceholderConfigurer propertyPlaceHolder() {
       PropertySourcesPlaceholderConfigurer propertyPlaceholder = new PropertySourcesPlaceholderConfigurer();
       return propertyPlaceholder;
       
    }
}

...

Database

The project is using a simple MySQL database. The SQL file resources/database/bootstrap.sql contains the queries necessary to create the database and the required tables.

###Data Model

A simple data model is used to play with Hibernate configuration. Basically, simple tables with primary/foreign keys. The following tables are created.

####Address Table: A table containing addresses ADDRESS

####Contact Table: A table containing contact details CONTACT

####Company Table: A table containing companies COMPANY that references ADDRESS and CONTACT

###Configuration

The properties to access to the database are located in resources/database/database.properties

####database.properties

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:8084/dohbedoh
jdbc.username=root
jdbc.password=admin

We use the mysql-connector-java, a JDBC driver for MySQL.

####pom.xml

...
<dependency>
	<groupId>mysql</groupId>
	<artifactId>mysql-connector-java</artifactId>
	<version>${mysql-connector.version}</version>
</dependency>
...

We use the mysql-connector-java (JDBC driver for MySQL), and a Apache DBCP2 (database connection pool).

####pom.xml

...

	<dependency>
		<groupId>mysql</groupId>
		<artifactId>mysql-connector-java</artifactId>
		<version>${mysql-connector.version}</version>
	</dependency>
	
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-dbcp2</artifactId>
        <version>${apache-dbcp.version}</version>
    </dependency>

...

####Project DataSource Structure

Project
 |  src
 |   |-main
 |   |   |-java
 |   |   |   |-com
 |   |   |       |-dohbedoh
 |   |   |           |-config
 |   |   |               |-DataSourceConfig.java

The data source is configured in com.dohbedoh.config.DataSourceConfig.java and make use of the properties set up in resources/database/database.properties. We use the annotation @PropertySource to add the 'database.properties' file to the Spring Environment through the PropertySourcePlaceholderConfigurer defined above.

####DataSourceConfig.java

...

@Configuration
@PropertySource("classpath:database/database.properties")
public class DataSourceConfig {

    @Value("${jdbc.driverClassName}")
    private String driverClassName;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;

    @Bean
    public DataSource dataSource() {

        BasicDataSource dataSource = new BasicDataSource();
        dataSource.setDriverClassName(driverClassName);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        return dataSource;
    }
}

...

Hibernate

####Project Hibernate Structure

Project
 |  src
 |   |-main
 |   |   |-java
 |   |   |   |-com
 |   |   |       |-dohbedoh
 |   |   |           |-config
 |   |   |               |-HibernateConfig.java
 |   |   |           |-model
 |   |   |               |-Company.java

The entry point of Hibernate configuration is com.dohbedoh.config.HibernateConfig.java. We set up the SessionFactory with Hibernate properties and specify com.dohbedoh.model as the package in which to find Hibernate Mapping Objects. We also set up a HibernateTransactionManager to which we attached the SessionFactory bean.

####HibernateConfig.java

...

    @Autowired
        private Environment environment;
    
        @Bean
        public LocalSessionFactoryBean setupSessionFactory(DataSource dataSource) {
            LocalSessionFactoryBean sessionFactoryBean = new LocalSessionFactoryBean();
            sessionFactoryBean.setDataSource(dataSource);
            sessionFactoryBean.setPackagesToScan("com.dohbedoh.model");
    
            Properties hibernateProperties = new Properties();
            hibernateProperties.setProperty("hibernate.dialect", environment.getProperty("hibernate.dialect"));
            hibernateProperties.setProperty("hibernate.show_sql", environment.getProperty("hibernate.show_sql"));
            hibernateProperties.setProperty("hibernate.format_sql", environment.getProperty("hibernate.format_sql"));
    
            sessionFactoryBean.setHibernateProperties(hibernateProperties);
            return sessionFactoryBean;
        }

    @Bean
    public PlatformTransactionManager transactionManager(
            SessionFactory sessionFactory,
            DataSource dataSource) {

        HibernateTransactionManager transactionManager = new HibernateTransactionManager();
        transactionManager.setSessionFactory(sessionFactory);
        transactionManager.setDataSource(dataSource);
        return transactionManager;
    }
}

...

Each model mapping is defined inside the corresponding model class under com.dohbedoh.model. Mapping by annotations is straight-forward and really similar to mapping with. We use JPA annotations which are supported by Hibernate. Some hibernate annotations are deprecated (for example @Entity).

####Company.java

...

@Entity
@Table(name = "COMPANY")
public class Company {

    @Id
    @GeneratedValue
    @Column(name = "COMPANY_ID", precision = 5, scale = 0)
    private int companyId;

    @Column(name = "COMPANY_NAME", length = 32, nullable = false)
    private String companyName;

    @Column(name = "COMPANY_ADDRESS_ID", precision = 5, scale = 0, nullable = false)
    private int addressId;

    @Column(name = "COMPANY_CONTACT_ID", precision = 5, scale = 0, nullable = false)
    private int contactId;

...

Testing

Coming soon...