Spring and Hibernate’s getCurrentSession() ErrorS!

If you are using Spring to wrap a Hibernate 

SessionFactory

 and you are not using Spring-managed transactions, you may run into an issue. The reason is that Spring by default will wrap Hibernate’s

SessionFactory

 implementation and delegate to its own transactional version. If you are just using the simple

ThreadLocal

-based session-per-request functionality, then when you attempt to open the 

Session

, you will get an

IllegalStateException

 thrown, with the error message 

"No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here"

. This happens because Spring’s 

SessionFactoryUtils

 checks if the Session is bound to Spring’s transactional support, and by default throws an error if it is not.

The solution to this is to set the property

<property name="exposeTransactionAwareSessionFactory"><value>false</value></property>

in the Spring config. This will return the “raw” 

SessionFactory

instead of the proxied one. A snippet of code from

AbstractSessionFactoryBean

 shows where the check is done:

[code]
/**
   * Wrap the given SessionFactory with a transaction-aware proxy, if demanded.
   * @param rawSf the raw SessionFactory as built by <code>buildSessionFactory()</code>
   * @return the SessionFactory reference to expose
   * @see #buildSessionFactory()
   * @see #getTransactionAwareSessionFactoryProxy
   */
  protected SessionFactory wrapSessionFactoryIfNecessary(SessionFactory rawSf) {
    if (isExposeTransactionAwareSessionFactory()) {
       return getTransactionAwareSessionFactoryProxy(rawSf);
    }
    else {
      return rawSf;
    }
  }

[/code]
A sample Spring config is shown below.

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="org.hsqldb.jdbcDriver"/>
<property name="url" value="jdbc:hsqldb:hsql://localhost:9001"/>
<property name="username" value="sa"/>
<property name="password" value=""/>
</bean>

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property [b]name="exposeTransactionAwareSessionFactory"><value>false</value></property>[/b]
<property name="annotatedPackages">
<list>
<value>uk.co.researchkitchen.hibernate</value>
</list>
</property>
<property name="annotatedClasses">
<list>
<value>uk.co.researchkitchen.hibernate.Product</value>
<value>uk.co.researchkitchen.hibernate.ProductDescription</value>
</list>
</property>
<property name="hibernateProperties">
<value>
hibernate.dialect=org.hibernate.dialect.HSQLDialect
hibernate.show_sql=true
hibernate.hbm2ddl.auto=create
hibernate.current_session_context_class=thread
</value>
</property>
</bean>

</beans>

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