<class name="Article" table="Article">
    <id name="id" type="long" column="id">
        <generator class="native"/>
    </id>
    <property name="title" column="title"/>
    <property name="keywords" column="keywords"/>
    <many-to-one name="catalog"  lazy="true"  class="Catalog">
        <column name="article_id"></column>
    </many-to-one>
    <set name="comments" inverse="true" cascade="all" lazy="true">
        <key column="article_id"/>
        <one-to-many  class="Comment" />
    </set>
    ...
    <joined-subclass name="News" table="News">
        <key column="id"/>
        <property name="page" column="page"/>
        <property name="pagesize" column="pagesize"/>
        ...
    </joined-subclass>
    <joined-subclass name="Falsh" table="Falsh">
        <key column="id"/>
        <property name="falshUrl" column="falshUrl"/>
        <property name="height" column="height"/>
        ...
    </joined-subclass>
    <joined-subclass name="Product" table="Product">
        <key column="id"/>
        <property name="pname" column="pname"/>
        <property name="psize" column="psize"/>
        ...
    </joined-subclass>
</class>

------解决方案--------------------
用hibernate自动生成工具生成bhm.xml等文件.