配置文件：
班級：
<hibernate-mapping>
 
 <class name="bjca.testHibernate.entity.impl.ClassInfo" table="t_class">
   <id name="claId" type="java.lang.Integer">
            <column name="claId" />
            <generator class="native" />
        </id>
  <property name="claName" type="java.lang.String">
            <column name="claName" length="50" not-null="true" />
        </property>
      
  <set name="students" inverse="true">
   <key column="classId"></key>
   <one-to-many class="bjca.testHibernate.entity.impl.StudentInfo"/>
  </set>
  
     </class>
</hibernate-mapping>

學生
<hibernate-mapping>
 
 <class name="bjca.testHibernate.entity.impl.StudentInfo" table="t_student">
   <id name="stuId" type="java.lang.Integer">
            <column name="id" />          
             <generator class="native" />
        </id>
  <property name="stuName" type="java.lang.String">
            <column name="stuName" length="50" not-null="true" />
        </property>
       
        <many-to-one name="classes" column="classId"

class="bjca.testHibernate.entity.impl.ClassInfo" cascade="all"/>
 </class>
</hibernate-mapping>

插入一個班級：
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Hibernate: select hibernate_sequence.nextval from dual
Hibernate: insert into t_class (claName, claId) values (?, ?)
11111

插入一個學生：
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Hibernate: select hibernate_sequence.nextval from dual
Hibernate: insert into t_student (stuName, classId, id) values (?, ?, ?)
11111

修改一條學生信息：
11111
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Hibernate: select studentinf0_.id as id0_, studentinf0_.stuName as stuName0_,

studentinf0_.classId as classId0_ from t_student studentinf0_ where studentinf0_.id=10
Hibernate: select classinfo0_.claId as claId1_, classinfo0_.claName as claName1_ from t_class

classinfo0_ where classinfo0_.claId=11
Hibernate: select studentinf0_.id as id0_0_, studentinf0_.stuName as stuName0_0_,

studentinf0_.classId as classId0_0_ from t_student studentinf0_ where studentinf0_.id=?
Hibernate: update t_student set stuName=?, classId=? where id=?
Hibernate: update t_class set claName=? where claId=?

修改一條班級信息：
11111
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Hibernate: select classinfo0_.claId as claId1_, classinfo0_.claName as claName1_ from t_class

classinfo0_ where classinfo0_.claId=11
Hibernate: update t_class set claName='大象二班' where claId=11

班級信息級聯 all
11111
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Hibernate: select studentinf0_.id as id0_, studentinf0_.stuName as stuName0_,

studentinf0_.classId as classId0_ from t_student studentinf0_ where studentinf0_.id=12
Hibernate: select classinfo0_.claId as claId1_, classinfo0_.claName as claName1_ from t_class

classinfo0_ where classinfo0_.claId=11
Hibernate: select studentinf0_.id as id0_0_, studentinf0_.stuName as stuName0_0_,

studentinf0_.classId as classId0_0_ from t_student studentinf0_ where studentinf0_.id=?
Hibernate: update t_class set claName=? where claId=?

結論：
1對多，多的那方 cascade="all"

**********************************
1方， 班級：       
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實體類包含set對象，放置多方對象 名自取

配置文件中配置<set>標記,標記name取本方實體中的對方set對象的名字，即set的名字 ,
<set> 下的 <key> 指向多方主鍵
<set> 下的 <one-to-many> 指向多方對象

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多方  學生：       
***********************************
實體類包含1方對象，名自取

配置文件中配置<many-to-one> 指向1方對象 name 屬性取本方實體方法中的對方對象的名字。