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I have recently started using Spring boot, and have run into a bit of a problem. before, when i was just using Spring data with hibernate and JPA, I could create a hibernate.cfg.xml file that would give a bunch of configuration that could be passed to a config object and then ultimately create a SessionFactory object that would create a Session object that could be used to pass the query to hibernate:

package util; import org.hibernate.SessionFactory; import org.hibernate.boot.registry.StandardServiceRegistryBuilder; import org.hibernate.cfg.Configuration; public class HibernateUtil { private static final SessionFactory sessionFactory = buildSessionFactory(); private static SessionFactory buildSessionFactory() { try { // Create the SessionFactory from hibernate.cfg.xml Configuration configuration = new Configuration().configure("hibernate.cfg.xml"); return configuration.buildSessionFactory( new StandardServiceRegistryBuilder().applySettings( configuration.getProperties() ).build() ); } catch (Throwable ex) { // Make sure you log the exception, as it might be swallowed System.err.println("Initial SessionFactory creation failed." + ex); throw new ExceptionInInitializerError(ex); } } public static SessionFactory getSessionFactory() { return sessionFactory; } }

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <!-- Database connection settings --> <property name="connection.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://localhost:3306/hello-world</property> <property name="connection.username">root</property> <property name="connection.password">password</property> <!-- SQL dialect --> <property name="dialect">org.hibernate.dialect.MySQLDialect</property> <!-- Create/update tables automatically using mapping metadata --> <property name="hbm2ddl.auto">update</property> <!-- Use Annotation-based mapping metadata --> <mapping class="entity.Author"/> <mapping class="entity.Article"/> </session-factory> </hibernate-configuration>

Main.java

 public class HelloWorldClient { public static void main(String[] args) { Session session = HibernateUtil.getSessionFactory().openSession(); Transaction txn = session.getTransaction(); EntityManagerFactory emf = Persiscance.createEntityManagerFactory("hibernate.cfg.xml"); EntityManager em = emf.createEntityManager(); EntityTransaction txn = em.getTransaction(); try { txn.begin(); Author author = new Author("name", listOfArticlesWritten); Article article = new Article("Article Title", author); session.save(author); session.save(article); Query query = session.createQuery("select distinct a.authorName from Article s where s.author like "Joe%" and title = 'Spring boot'); List<Article> articles = query.list(); txn.commit(); } catch(Exception e) { if(txn != null) { txn.rollback(); } e.printStackTrace(); } finally { if(session != null) { session.close(); } } } }

This is where the issue appears. I don't know how to avoid creating a hibernate.cfg.xml file or session factory for custom queries. in the Spring guides page, and some tutorials i have worked through, they take their DAO and extend the CrudRepository interface which gives a bunch of methods already, as well as a way to name the method so that Hibernate can build the sql on its own.

what i am trying to accomplish, at least in this post is to be able to execute the above query in spring boot. I can create a properties file

application.properties

# =============================== # = DATA SOURCE # =============================== # Set here configurations for the database connection spring.datasource.url = jdbc:mysql://localhost:3306/spring-boot-demo spring.datasource.username = test spring.datasource.password = test # Mysql connector spring.datasource.driverClassName = com.mysql.jdbc.Driver # =============================== # = JPA / HIBERNATE # =============================== # Specify the DBMS spring.jpa.database = MYSQL # Show or not log for each sql query spring.jpa.show-sql = true # Ddl auto must be set to "create" to ensure that Hibernate will run the # import.sql file at application startup #create-drop| update | validate | none spring.jpa.hibernate.ddl-auto = update # SQL dialect for generating optimized queries spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect # =============================== # = THYMELEAF # =============================== spring.thymeleaf.cache = false #debug=true

I can move all but the mapping to a properties file, but then I am unclear how to write the query because there is no longer a session object.

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If you use Spring Boot + Spring Data JPA, then you configure your datasource (which you now put in hibernate.cfg.xml) into the application.properties, by using the spring.datasource.* properties.

This should automatically create an entity manager for you. If you need to use queries, you can use Spring Data JPA's repositories, for example:

public interface ArticleRepository extends JpaRepository<Article, Long> { @Query("select s from Article s where s.author like ?1 and s.title = ?2") List<Article> findByAuthorAndTitle(String author, String title); }

Now you can autowire the repository and use the given query, like this:

List<Article> articles = repository.findByAuthorAndTitle("Joe%", "Spring boot");

If you really need custom queries, you can use the Predicate/Criteria API from JPA. Spring offers a wrapped version of these predicates, called Specifications.

To do that, you extend your ArticleRepository with another interface called JpaSpecificationExecutor<Article>. This adds some extra methods to your repository:

Specification<Article> spec = Specifications.<Article>where((root, query, cb) -> { return cb.and( cb.like(root.get("author"), "Joe%"), cb.equal(root.get("title"), "Spring boot")); }); List<Article> articles = repository.findAll(spec);

This allows you to dynamically create queries, though from your question it doesn't look like you really need it.

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In spring boot application you no need to create xml configuration, you must congigure java file itself. Check with this example,

import java.util.Properties; import javax.sql.DataSource; import org.hibernate.annotations.common.util.impl.LoggerFactory; import org.springframework.beans.factory.annotation.Value; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.jdbc.datasource.DriverManagerDataSource; import org.springframework.orm.hibernate4.HibernateTransactionManager; import org.springframework.orm.hibernate4.LocalSessionFactoryBean; @Configuration public class DatabaseConfig { private org.jboss.logging.Logger log = LoggerFactory.logger(DatabaseConfig.class); @Value("${db.driver}") private String DB_DRIVER; @Value("${db.username}") private String DB_USERNAME; @Value("${db.password}") private String DB_PASSWORD; @Value("${db.url}") private String DB_URL; @Value("${hibernate.dialect}") private String HIBERNATE_DIALECT; @Value("${hibernate.show_sql}") private String HIBERNATE_SHOW_SQL; @Value("${hibernate.hbm2ddl.auto}") private String HIBERNATE_HBM2DDL_AUTO; @Value("${entitymanager.packagesToScan}") private String ENTITYMANAGER_PACKAGES_TO_SCAN; @Bean public DataSource dataSource() { DriverManagerDataSource dataSource = null; try { dataSource = new DriverManagerDataSource(); dataSource.setDriverClassName(DB_DRIVER); dataSource.setUrl(DB_URL); dataSource.setUsername(DB_USERNAME); dataSource.setPassword(DB_PASSWORD); } catch (Exception e) { e.getMessage(); } return dataSource; } @Bean public LocalSessionFactoryBean sessionFactory() { LocalSessionFactoryBean sessionFactoryBean = new LocalSessionFactoryBean(); sessionFactoryBean.setDataSource(dataSource()); sessionFactoryBean.setPackagesToScan(ENTITYMANAGER_PACKAGES_TO_SCAN); Properties hibernateProps = new Properties(); hibernateProps.put("hibernate.dialect", HIBERNATE_DIALECT); hibernateProps.put("hibernate.show_sql", HIBERNATE_SHOW_SQL); hibernateProps.put("hibernate.hbm2ddl.auto", HIBERNATE_HBM2DDL_AUTO); sessionFactoryBean.setHibernateProperties(hibernateProps); return sessionFactoryBean; } @Bean public HibernateTransactionManager transactionManager() { HibernateTransactionManager transactionManager = new HibernateTransactionManager(); transactionManager.setSessionFactory(sessionFactory().getObject()); return transactionManager; } }

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