spring+hibernate1对1关联中ClassCastException

xml:
customer:
<hibernate-mapping>
<class name="vo.CusInfo" table="customer" lazy="false">
<id name="id" column="id" type="java.lang.Long">
<generator class="increment"></generator>
</id>
<property name="cid" column="cId" type="string"></property>
<property name="cpwd" column="cPassword" type="string"></property>
<property name="csex" column="cSex" type="string"></property>
<property name="caddress" column="cAddress" type="string"></property>

<set name="order" cascade="save-update" inverse="true">
<key column="cid"></key>
<one-to-many class="vo.OrderInfo"/>
</set>
</class>Order:
<hibernate-mapping>
<class name="vo.OrderInfo" table="orderInfo">
<id name="id" column="id" type="java.lang.Long">
<generator class="increment"></generator>
</id>
<property name="oname" column="orderName" type="string"></property>
<many-to-one name="cus" class="vo.CusInfo" column="cid" lazy="false">
</many-to-one>
<map name="myorderdetail" table="orderDetail" cascade="save-update" inverse="false">
<key column="id"></key>
<index column="orderid" type="java.lang.Long"></index>
<composite-element class="vo.OrderDetail">
<parent name="myorder"/>
<property name="totalprice" column="totalprice" type="java.lang.Double"></property>
<property name="pid" column="pId" type="java.lang.Long"></property>
</composite-element>
</map>
</class>