Exception handling using hibernate template in Spring framework - spring

Question

I am using Spring with Hibernate in my project.There are many methods written in DAO implementation java file and every method is using the same try/catch/finally lines of code which seem redundant to me.
I am told to optimize/refactor the code since the file LOC exceeds 10k.I read somewhere that using HibernateDaoSupport we need not to worry about exceptions or closing the session. It will be taken care of by Spring itself.
Could somebody please help me how to proceed or do the needful or any better way to handle exceptions?I am pasting below code of one method in DAO layer.
public class CSDDaoImpl extends HibernateDaoSupport implements CSDDao {
public Deal getDealStructure(long dealId) throws CSDServiceException {
Session session = null;
try {
session = getSession();
Deal deal = (Deal) session.createCriteria(Deal.class).add(
Restrictions.eq("dealId", dealId)).uniqueResult();
return deal;
} catch (DataAccessResourceFailureException darfex) {
String message = "Failed to retrieve the deal object.";
CSDServiceException ex = new CSDServiceException(message, darfex);
ex.setStackTrace(darfex.getStackTrace());
ex.setErrorCode(Constants.DATA_ACCESS_FAILURE_EXP);
ex.setMessageToUser(message);
throw ex;
} catch (IllegalStateException isex) {
String message = "Failed to retrieve the deal object.";
CSDServiceException ex = new CSDServiceException(message, isex);
ex.setStackTrace(isex.getStackTrace());
ex.setErrorCode(Constants.ILLEGAL_STATE_EP);
ex.setMessageToUser(message);
throw ex;
} catch (HibernateException hbex) {
String message = "Failed to retrieve the deal object.";
CSDServiceException ex = new CSDServiceException(message, hbex);
ex.setStackTrace(hbex.getStackTrace());
ex.setErrorCode(Constants.HIBERNATE_EXP);
ex.setMessageToUser(message);
throw ex;
} finally {
if (session != null && session.isOpen()) {
try {
session.close();
} catch (HibernateException hbex) {
log.error("Failed to close the Hibernate Session.", hbex);
hbex.printStackTrace();
CSDServiceException ex = new CSDServiceException(
"Failed to close the Hibernate Session.", hbex);
ex.initCause(hbex.getCause());
ex.setStackTrace(hbex.getStackTrace());
throw ex;
}
}
}
}
}

Answer 1

The best approach of handling exceptions is i believe through writing an Exception Interceptor to intercept all your DAO calls and you can catch the ones you only need in your application and wrap it with your own custom application specific exceptions.
You definitely do not need to work directly with session once an exception is thrown. That would defeat the purpose of using HibernateDaoSupport and Spring.
Have a look at this link : http://static.springsource.org/spring/docs/current/spring-framework-reference/html/classic-spring.html
Hope that helps.