多表继承：
Bean：
public class Person implements Serializable{ ???private int id ; ???????private String name ; ???????private int age ;}public class Student extends Person implements Serializable { ???????private String dream ; ???????private Date birthday ;}public class Teacher extends Person implements Serializable{ ???private String job ; ???????private boolean merry ;}xml（在同一个表中，加一个字段来区分类型）：
Person.hbm.xml：<class name = "Person" discriminator-value="p"> ???????<id name = "id"> ???????????<generator class="native" /> ???????</id> ???????<!-- discriminator 是新建一个列,此列用来区分对象具体的类型 ?????????????discriminator-value 定义插入一个具体的对象的时候,自动向type列中插入指定的值 ???????--> ???????<discriminator column="type" /> ???????<property name="name" /> ???????<property name="age" /> ???????????????<subclass name = "Teacher" discriminator-value="t"> ????????????<property name="job" /> ????????????<property name="merry" /> ???????</subclass> ???????????????<subclass name = "Student" discriminator-value="s"> ????????????<property name="dream" /> ????????????<property name="birthday" /> ???????</subclass> ???</class> ???
xml（在不同表中）：
Person.hbm.xml:<class name = "Person"> ???????<id name = "id"> ???????????<generator class="native" /> ???????</id> ???????????????<property name="name" /> ???????<property name="age" /> ???????????????<joined-subclass name="Teacher" table="Teacher"> ???????????<key column="pid" /> ???????????<property name="job" /> ???????????<property name="merry" /> ???????</joined-subclass> ???????????????<joined-subclass name="Student" table="Student"> ???????????<key column="pid" /> ???????????<property name="dream" /> ???????????<property name="birthday" /> ???????</joined-subclass> ???????????</class>
Hibernate映射关系配置（五）
原文地址：http://www.cnblogs.com/hyl-home/p/7577019.html