Failed to convert property value of type 'org.apache.ibatis.session.defaults.DefaultSqlSessionFactory' to required type 'java.lang.String' for property 'sqlSessionFactoryBeanName';

<bean id="mySqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">  
        <property name="dataSource" ref="dataSource" />  
        <!-- 自动扫描mapping.xml文件 -->  
        <property name="mapperLocations" value="classpath:com/map/UserMapper.xml"></property>  
    </bean>  
 
    <!-- 所在包名，Spring会自动查找其下的类 -->  
   <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">  
        <property name="basePackage" value="com.dao" />  
        <property name="sqlSessionFactoryBeanName" value="mySqlSessionFactoryBean"></property>
    </bean>

之前是<property name="sqlSessionFactoryBeanName" ref="mySqlSessionFactoryBean"></property>，使用ref取不到mySqlSessionFactoryBean的值