两种获取hibernate会话的区别

@Repository("demoDao")
public class DemoDaoImpl extends HibernateDaoSupport implements DemoDao{
    //通过getSession方法获取
    @Override
    public Demo method1(final Integer param) {
        Session session = this.getSession();
        ...
    }

    //通过getHibernateTemplate().execute方法获取
    @Override
    public Demo method2(final Integer param) {
        return getHibernateTemplate().execute(new HibernateCallback<Demo>() {
            @Override
            public AppPzTestStats doInHibernate(Session session) throws HibernateException, SQLException {
                ...
            }
        });
    }
}

/**
 * Obtain a Hibernate Session, either from the current transaction or
 * a new one. The latter is only allowed if the
 * {@link org.springframework.orm.hibernate3.HibernateTemplate#setAllowCreate "allowCreate"}
 * setting of this bean's {@link #setHibernateTemplate HibernateTemplate} is "true".
 * <p><b>Note that this is not meant to be invoked from HibernateTemplate code
 * but rather just in plain Hibernate code.</b> Either rely on a thread-bound
 * Session or use it in combination with {@link #releaseSession}.
 * <p>In general, it is recommended to use HibernateTemplate, either with
 * the provided convenience operations or with a custom HibernateCallback
 * that provides you with a Session to work on. HibernateTemplate will care
 * for all resource management and for proper exception conversion.
 * @return the Hibernate Session
 * @throws DataAccessResourceFailureException if the Session couldn't be created
 * @throws IllegalStateException if no thread-bound Session found and allowCreate=false
 * @see org.springframework.orm.hibernate3.SessionFactoryUtils#getSession(SessionFactory, boolean)
 * @deprecated as of Spring 3.2.7, in favor of {@link HibernateTemplate} usage
 */
@Deprecated
protected final Session getSession() throws DataAccessResourceFailureException, IllegalStateException {
	return getSession(this.hibernateTemplate.isAllowCreate());
}

/**
 * Execute the action specified by the given action object within a
 * {@link org.hibernate.Session}.
 * <p>Application exceptions thrown by the action object get propagated
 * to the caller (can only be unchecked). Hibernate exceptions are
 * transformed into appropriate DAO ones. Allows for returning a result
 * object, that is a domain object or a collection of domain objects.
 * <p>Note: Callback code is not supposed to handle transactions itself!
 * Use an appropriate transaction manager like
 * {@link HibernateTransactionManager}. Generally, callback code must not
 * touch any {@code Session} lifecycle methods, like close,
 * disconnect, or reconnect, to let the template do its work.
 * @param action callback object that specifies the Hibernate action
 * @return a result object returned by the action, or {@code null}
 * @throws org.springframework.dao.DataAccessException in case of Hibernate errors
 * @see HibernateTransactionManager
 * @see org.hibernate.Session
 */
<T> T execute(HibernateCallback<T> action) throws DataAccessException;