Question

I use Spring with Hibernate and get always a NPE for the sessionFactory Object.

My config file:

@Configuration
public class HibernateConfiguration {

@Bean
public AnnotationSessionFactoryBean sessionFactory() {
    Properties props = new Properties();
    props.put("hibernate.dialect", MySQL5InnoDBDialect.class.getName());
    props.put("hibernate.format_sql", "true");
    props.put("hibernate.connection.driver_class", "com.mysql.jdbc.Driver");
    props.put("hibernate.connection.password", "xxx");
    props.put("hibernate.connection.url", "jdbc:mysql://localhost/Market");
    props.put("hibernate.connection.username", "philipp");

    AnnotationSessionFactoryBean bean = new AnnotationSessionFactoryBean();
    bean.setAnnotatedClasses(new Class[] { xxx.class, xxx.class, xxx.class });
    bean.setHibernateProperties(props);
    bean.setSchemaUpdate(true);
    return bean;
}





@Bean
public HibernateTransactionManager transactionManager() {
    return new HibernateTransactionManager(sessionFactory().getObject());
}

@Bean
public PersistenceExceptionTranslationPostProcessor persistenceExceptionTranslationPostProcessor() {
    return new PersistenceExceptionTranslationPostProcessor();
}

}

My DAOImpl class:

@Repository("xxx")
public class xxxDAOImpl implements xxxDAO {

private SessionFactory sessionFactory;

@Autowired
public void setSessionFactory(SessionFactory sessionFactory) {
    this.sessionFactory = sessionFactory;
}

private Session currentSession() {
    return sessionFactory.getCurrentSession();
}
...

Testcase:

@ContextConfiguration
@RunWith(SpringJUnit4ClassRunner.class)
public class TestxxxDAOImpl {

@Test
@Transactional
public void testInsertxxx() throws Exception {

    xxxDAO xxxDAO = new xxxDAOImpl();
    xyz xyz = new xyz();
    xxxDAO.insert(xyz);
    assertNotNull(xyz.getId());
    }

}

app-context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"     xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"   xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xsi:schemaLocation="
    http://www.springframework.org/schema/jdbc   http://www.springframework.org/schema/jdbc/spring-jdbc-3.0.xsd
    http://www.springframework.org/schema/beans   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">


<tx:annotation-driven transaction-manager="transactionManager" />
<context:component-scan base-package="xxx.config" />
<context:component-scan base-package="xxx.dao" />
<context:annotation-config></context:annotation-config>

test-context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xsi:schemaLocation="http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.0.xsd
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

<import resource="classpath:/META-INF/spring/app-context.xml" />

I get always an NPE from the currentSession when the test calls the insert method.

public void insert(xxx xxx) {
    currentSession().save(xxx);
}


private Session currentSession() {
    return sessionFactory.getCurrentSession();
}

Answer 1

The very first thing to understand when working with Spring is that Spring dependency injection only works for beans obtained from the application context, not for beans created with new.

In Spring-enabled unit tests you configure application context using @ContextConfiguration, for example, as follows (works in Spring 3.1, in previous versions @ContextConfiguration doesn’t take @Configuration classes directly, therefore you’ll have to create XML configuration file):

@Configuration 
public class HibernateConfiguration { 
    // Add your DAO to application context
    @Bean
    public xxxDAO xxxDAO() {
        return new xxxDAOImpl();
    }
    ...
}

// Configure application context using the given @Configuration class
@ContextConfiguration(classes = HibernateConfiguration.class)   
@RunWith(SpringJUnit4ClassRunner.class)
public class TestxxxDAOImpl {
    // Obtain DAO from the application context    
    @Autowired xxxDao xxxDao;
    ...
}