hibernate配置复合主键报错，请大侠看看格式哪里错了，研究很多天了，急！

[ytnice]

运行错误如下：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in ServletContext resource [/WEB-INF/applicationContext.xml]: Invocation of init method failed; nested exception is org.hibernate.InvalidMappingException: Could not parse mapping document from invalid mapping

org.hibernate.InvalidMappingException: Could not parse mapping document from invalid mapping

org.xml.sax.SAXParseException: The content of element type "class" must match "(meta*,subselect?,cache?,synchronize*,comment?,tuplizer*,(id|composite-id),discriminator?,natural-id?,(version|timestamp)?,(property|many-to-one|one-to-one|component|dynamic-component|properties|any|map|set|list|bag|idbag|array|primitive-array)*,((join*,subclass*)|joined-subclass*|union-subclass*),loader?,sql-insert?,sql-update?,sql-delete?,filter*,resultset*,(query|sql-query)*)".

我的hibernate配置文件如下：
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >

<hibernate-mapping package="com.freejava.hibernate.model">
<class
name="UserMailbox"
table="USERMAILBOX"
>
<meta attribute="sync-DAO">false</meta>

<composite-id name="userMailboxPK" class="com.freejava.hibernate.model.UserMailboxPK">
<key-property name="id" column="ID" type="java.lang.Integer" length="10" />
<key-property name="mailAddress" column="MAILADDRESS" type="java.lang.String" length="32" />
</composite-id>

<property
name="senderName"
column="SENDERNAME"
type="string"
not-null="true"
length="10"
/>
<property
name="mailType"
column="MAILTYPE"
type="string"
not-null="true"
length="10"
/>

</class>
</hibernate-mapping>

[denghan]

<composite-id name="id" class="com.freejava.hibernate.model.UserMailboxPK">
<key-many-to-one name="user" class="com.freejava.hibernate.model.User">
<column name="ID" length="20" />
</key-many-to-one>
<key-property name="mailAddress" type="java.lang.String">
<column name="MAILADDRESS" length="32"/>
</key-property>
</composite-id>