spring声明式事务有关问题，很纠结

@Repository("userDAO")public class UserDAOImpl implements UserDAO {        private HibernateTemplate hibernateTemplate;    @Resource//让spring注入进来    public void setHibernateTemplate(HibernateTemplate hibernateTemplate) {        this.hibernateTemplate = hibernateTemplate;    }    public void add(User u) {        hibernateTemplate.save(u);    }}

@Repository("logDAO")public class LogDAOImpl implements LogDAO {    private HibernateTemplate hibernateTemplate;        @Resource//让spring注入进来    public void setHibernateTemplate(HibernateTemplate hibernateTemplate) {        this.hibernateTemplate = hibernateTemplate;    }    @Override    public void add(Log log) {        System.out.println("调用了LogDAO的add方法！");        hibernateTemplate.save(log);        throw new RuntimeException("日志打印异常！");    }}

@Service("userService")public class UserServiceImpl implements UserService{    private UserDAO userDAO;    private LogDAO logDAO;    public UserDAO getUserDAO() {        return userDAO;    }    public LogDAO getLogDAO() {        return logDAO;    }    @Resource    public void setLogDAO(LogDAO logDAO) {        this.logDAO = logDAO;    }    @Resource    public void setUserDAO(UserDAO userDAO) {        this.userDAO = userDAO;    }        @Transactional    public void add(User u){        logDAO.add(new Log("a user saved!"));        userDAO.add(u);    }    }

<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: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-3.0.xsd         http://www.springframework.org/schema/context     http://www.springframework.org/schema/context/spring-context-3.0.xsd         http://www.springframework.org/schema/aop     http://www.springframework.org/schema/aop/spring-aop-3.0.xsd    http://www.springframework.org/schema/tx     http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">    <!--把com.hktk包下的东西交给spring管理 -->    <context:component-scan base-package="com.hktk" />        <!-- 加载properties文件 -->    <context:property-placeholder location="classpath:jdbc.properties" />    <!-- 配置数据源 -->    <bean id="dataSource" destroy-method="close"        class="org.apache.commons.dbcp.BasicDataSource">        <property name="driverClassName" value="${jdbc.driverClassName}" />        <property name="url" value="${jdbc.url}" />        <property name="username" value="${jdbc.username}" />        <property name="password" value="${jdbc.password}" />    </bean>    <!-- 配置sessionFactory -->    <bean id="sessionFactory"        class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">        <property name="dataSource" ref="dataSource" />        <property name="annotatedClasses">            <list>                <value>com.hktk.entity.user.User</value>                <value>com.hktk.entity.log.Log</value>            </list>        </property>        <property name="hibernateProperties">            <props>                <prop key="hibernate.dialect">                    org.hibernate.dialect.MySQL5Dialect                </prop>                <prop key="hibernate.show_sql">true</prop>                <prop key="hibernate.hbm2ddl.auto">update</prop>                <prop key="hibernate.format_sql">true</prop>            </props>        </property>    </bean>    <!-- 下面这两个配置是使用Spring整合Hibernate的声明式事务的annotation写法 -->    <tx:annotation-driven transaction-manager="transactionManager"/>    <bean id="transactionManager"          class="org.springframework.orm.hibernate3.HibernateTransactionManager">            <property name="sessionFactory" ref="sessionFactory"/>    </bean>    <!-- 使用hibernateTemplate配置-->    <bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate">        <!-- hibernateTemplate中的sessionFactory由下面注入给它 -->        <property name="sessionFactory" ref="sessionFactory"></property>    </bean></beans>