用jboss的连接池错误

我的hiberante.cfg.xml:
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="hibernate.use_outer_join">true</property>
<property name="hibernate.session_factory_name">java:hibernate/SessionFactory</property>
    <property name="hibernate.transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>

<mapping resource="com/xinyuan/model/pojo/Navi.hbm.xml" />
jboss下mysql-ds.xml:
<local-tx-datasource>
    <jndi-name>MySqlDS</jndi-name>
    <connection-url>jdbc:mysql://localhost:3306/longzhiyin</connection-url>
    <driver-class>com.mysql.jdbc.Driver</driver-class>
    <user-name>root</user-name>
    <password>root</password>
    <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name>
    <metadata>
       <type-mapping>mySQL</type-mapping>
    </metadata>
  </local-tx-datasource>
测试代码：
NaviDAO ndao = new NaviDAO();
Navi navi = new Navi();
navi.setNaviName("产品展示");
navi.setNaviSequence(4);
navi.setNaviInsertDate(new Date());
navi.setNaviUpdateDate(new Date());
ndao.getSession().beginTransaction().begin();
ndao.save(navi);
ndao.getSession().beginTransaction().commit();
运行时报如下错误：
log4j:WARN No appenders could be found for logger (com.xinyuan.model.dao.NaviDAO).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "main" java.lang.UnsupportedOperationException: The user must supply a JDBC connection
at org.hibernate.connection.UserSuppliedConnectionProvider.getConnection(UserSuppliedConnectionProvider.java:30)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:423)
at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:144)
at org.hibernate.jdbc.AbstractBatcher.prepareSelectStatement(AbstractBatcher.java:123)
at org.hibernate.id.IncrementGenerator.getNext(IncrementGenerator.java:83)
at org.hibernate.id.IncrementGenerator.generate(IncrementGenerator.java:44)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:99)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:187)
at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:33)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:172)
at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:27)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
at org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:535)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:523)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:519)
at com.xinyuan.model.dao.NaviDAO.save(NaviDAO.java:34)
at com.xinyuan.test.ConTest.main(ConTest.java:23)
是什么原因呢？？？