hibernate单向关联hbm.xml和annotation方式

1、many-to-one单向关联:
a).hbm.xml配置以下：

<class name="Person">
	<id name="id" column="personId">
		<generator class="native"/>
	</id>
	<many-to-one name="address" column="addressId" not-null="true"/>
</class>

<class name="Address">
	<id name="id" column="addressId">
		<generator class="native"/>
	</id>
</class>

<class name="P