Myeclipse配置Tomcat Jndi数据源有关问题

Myeclipse配置Tomcat Jndi数据源问题
我做了一个非常简单的Hiernate的程序,用普通的jdbc是没问题的,但是如果用tomcat的JNDI数据源就有问题了,出现错误:
xception   in   thread   "main "   org.hibernate.HibernateException:   Could   not   find   datasource
at   org.hibernate.connection.DatasourceConnectionProvider.configure(DatasourceConnectionProvider.java:56)
at   org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider(ConnectionProviderFactory.java:124)
at   org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider(ConnectionProviderFactory.java:56)
at   org.hibernate.cfg.SettingsFactory.createConnectionProvider(SettingsFactory.java:366)
at   org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:60)
at   org.hibernate.cfg.Configuration.buildSettings(Configuration.java:1881)
at   org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1174)
at   hinernate.HiberOperator. <init> (HiberOperator.java:21)
at   hinernate.Test.main(Test.java:14)
Caused   by:   javax.naming.NoInitialContextException:   Cannot   instantiate   class:     [Root   exception   is   java.lang.ClassNotFoundException:   ]
at   javax.naming.spi.NamingManager.getInitialContext(Unknown   Source)
at   javax.naming.InitialContext.getDefaultInitCtx(Unknown   Source)
at   javax.naming.InitialContext.init(Unknown   Source)
at   javax.naming.InitialContext. <init> (Unknown   Source)
at   org.hibernate.util.NamingHelper.getInitialContext(NamingHelper.java:28)
at   org.hibernate.connection.DatasourceConnectionProvider.configure(DatasourceConnectionProvider.java:52)
...   8   more
Caused   by:   java.lang.ClassNotFoundException:  
at   java.lang.Class.forName0(Native   Method)
at   java.lang.Class.forName(Unknown   Source)
at   com.sun.naming.internal.VersionHelper12.loadClass(Unknown   Source)
...   14   more

但是我的数据源是存在并且可用的,我的hibernat.cfg.xml是:
<?xml   version= '1.0 '   encoding= 'UTF-8 '?>
<!DOCTYPE   hibernate-configuration   PUBLIC
                    "-//Hibernate/Hibernate   Configuration   DTD   3.0//EN "
                    "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd ">

<!--   Generated   by   MyEclipse   Hibernate   Tools.                                       -->
<hibernate-configuration>

<session-factory>
<property   name= "connection.datasource "> java:comp/env/jdbc/MyJndi </property>
 
<property   name= "connection.username "> root </property>
<property   name= "connection.password "> root </property>

<property   name= "dialect "> org.hibernate.dialect.MySQLDialect </property>

<property   name= "jndi.url "> jdbc:mysql://localhsot:3306/FishDB </property>
<property   name= "jndi.class "> </property>

<mapping   resource= "bean/Stockinfo.hbm.xml "   />
 
</session-factory>

</hibernate-configuration>

请问高手是什么原因呢?谢谢

------解决方案--------------------