hibernate关联映射总结
映射关系对象模型映射文件多对一外键关联映射

user：

?private int id;
?
?private String name;
?
?private Group group;

-------------------------------

group：

private int id;
?
private String name;

<class name="包路径.User" table="t_user">
??<id name="id">
???<generator column="groupid"/>
?</class>

--------------------------------------

<class name="包路径.Group"table="t_group">
??<id name="id">
???<generator constrained="true"/>
?</class>

---------------------------------------

<class name="包路径.IdCard" table="t_idcard">
??<id name="id">
???<generator unique="true"/>

------------------------------------------

<class name="包路径.IdCard" table="t_idcard">
??<id name="id">
???<generator unique="true"/>
?</class>

------------------------------------------

<class name="com.bjsxt.hibernate.IdCard" table="t_idcard">
??<id name="id">
???<generator property-ref="idCard"/>
?</class>

student：

?private int id;
?
?private String name;

------------------------------

classes：

?private int id;
?
?private String name;
?
?private Set students;

?

<class ame="包路径.Student"table="t_student">
??<id name="id">
???<generator table="t_classes">
??<id name="id">
???<generator column="classesid"/>

-------------------------------------------

<class name="包路径.lasses" table="t_classes">
??<id name="id">
???<generator inverse="true" cascade="all">
???<key column="classesid"/>
???<one-to-many class="Student"/>
??</set>
?</class>