1、在学习hibernate的一对多多对一关系的时候，出现了一下错误：
2、错误原因：
这是因为在配置student.hbm.xml的配置文件的时候出现了将两个属性映射到同一个字段：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="pers.zhb.domain">
<class name="Student" table="student">
<id name="studentno" column="studentno" >
<generator class="native"></generator>
</id>
<property name="birthday" column="birthday"></property>
<property name="classno" column="classno" ></property>
<property name="email" column="email"></property>
<property name="phone" column="phone"></property>
<property name="sex" column="sex"></property>
<property name="sname" column="sname"></property>
<property name="point" column="point"></property>
<many-to-one name="aClas" column="classno" class="Clas"></many-to-one>
</class>
</hibernate-mapping>
3、解决方案：
<property name="birthday" column="birthday"></property>
<property name="classno" column="classno" insert="false" update="false"></property>
<property name="email" column="email"></property>
<property name="phone" column="phone"></property>
<property name="sex" column="sex"></property>
<property name="sname" column="sname"></property>
<property name="point" column="point"></property>
<many-to-one name="aClas" column="classno" class="Clas"></many-to-one>
在属性的映射配置的地方加入insert=”false” update=”false”语句。