以下配置只针对多对多关系中的字段,别的不需要写,你应该会
类三的private Long qgServiceCategory_id;改为对象吧
实体类一的映射文件
<set name="serviceCategorys" inverse="true">
<key>
<column name="id" precision="10" scale="0" not-null="true" />
</key>
<one-to-many class="类三" />
</set>
实体类二
<set name="qgOffices" inverse="true">
<key>
<column name="id" precision="10" scale="0" not-null="true" />
</key>
<one-to-many class="类三" />
</set>
实体类三
<many-to-one name="office" class="office的类" fetch="select">
<column name="表三id或id2" precision="10" scale="0" not-null="true" />
</many-to-one>
<many-to-one name="qgServiceCategory" class="oqgServiceCategory对应的类" fetch="select">
<column name="表三id或id2" precision="10" scale="0" not-null="true" />
</many-to-one>
因为你的表述不太清楚所以只能给个模型,按这样改就行了