IllegalArgumentException occurred calling getter 总有这个异常

Question

<id name="stuId" type="java.lang.Integer" unsaved-value="0">
            <column name="stu_id" />
            <generator class="native" />
        </id>
有必要吗? 映射表出了两个stuId   Getter时肯定有突出.有了多对一的关系.主表就不要再设主键了.

Answer 1

<class name="org.libo.db.Student" table="student">
<set name="courses" table="course_student_table" cascade="save-update" inverse="false" lazy="false">
        <key column="stu_id"></key>
        <many-to-many class="org.libo.db.Student" column="cou_id"></many-to-many>
        </set>
怎么影射的啊？ 
<set name="courses" table="course_student_table" cascade="save-update" inverse="false" lazy="false">
        <key column="stu_id"></key>
        <many-to-many class="org.libo.db.Course" column="cou_id"></many-to-many>
        </set>

Answer 2

<set name="courses" table="class_course" cascade="persist">
      <key column="classid" />
      <many-to-many class="Course" column="courseid" foreign-key="fk_course"/>
    </set><set name="classes" table="class_course" inverse="true">
      <key column="courseid" />
      <many-to-many class="Class" column="classid" foreign-key="fk_class"/>
    </set>

Answer 3

兄弟，跟你类似的问题，多对多，主键由序列Sequence生成，但取主键的时候貌似出了问题：09:30:19,660 ERROR [BasicPropertyAccessor] IllegalArgumentException in class: org.domain.jbossseamtmsoa.entity.Role, getter method of property: roleid
09:30:19,661 ERROR [AbstractFlushingEventListener] Could not synchronize database state with session
org.hibernate.PropertyAccessException: IllegalArgumentException occurred calling getter of org.domain.jbossseamtmsoa.entity.Role.roleid
....
Caused by: java.lang.IllegalArgumentException: object is not an instance of declaring class
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.hibernate.property.BasicPropertyAccessor$BasicGetter.get(BasicPropertyAccessor.java:169)
... 103 more
09:30:19,668 SEVERE [application] javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: IllegalArgumentException occurred calling getter of org.domain.jbossseamtmsoa.entity.Role.roleid
javax.faces.el.EvaluationException: javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: IllegalArgumentException occurred calling getter of org.domain.jbossseamtmsoa.entity.Role.roleid
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:102)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
at javax.faces.component.UICommand.broadcast(UICommand.java:387)
....