用Spring调整hibernate不能自动建表

<bean id="dataSource" destroy-method="close"        class="org.apache.commons.dbcp.BasicDataSource">        <property name="driverClassName" value="com.mysql.jdbc.Driver" />        <property name="url"            value="jdbc:mysql:///test?useUnicode=true&amp;characterEncoding=GBK" />        <property name="username" value="root" />        <property name="password" value="root" />    </bean>    <bean id="sessionFactory"        class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">        <property name="dataSource" ref="dataSource" />        <property name="mappingResources">            <list>                <value>cn/dragon/books/model/Books.hbm.xml</value>            </list>        </property>        <property name="hibernateProperties">            <props>                <prop key="hibernate.dialect">                    org.hibernate.dialect.MySQLDialect                </prop>                <prop key="hibernate.hbm2ddl.auto">                    update                </prop>                <prop key="hibernate.show_sql">                    false                </prop>                <prop key="hibernate.format_sql">                    false                </prop>            </props>        </property>    </bean>