A.java 
private Long id;
private String name;
private TArea tarea;
.....A.hbm.xml<id name="id" type="java.lang.Long">
            <column name="ID" precision="38" scale="0" />
            <generator class="increment" />
        </id>
         <property name="name" type="java.lang.String">
            <column name="NAME" />
        </property>
 <one-to-one name="tarea" class="com.wprss.vo.TArea" cascade="all"></one-to-one>B.java
  private Long areaid;
  private String areaname;
  private Tree tree;
....B.hbm.xml <id name="areaid" type="java.lang.Long">
            <column name="AREAID" precision="38" scale="0" />
           <generator class="foreign" > 
             <param name="property">tree</param> 
            </generator> 
        </id>
 <one-to-one name="tree" class="com.wprss.vo.Tree"></one-to-one> 
有什么问题吗 这样配置 为什么会出现多余的left join语句呢