mybatis的多对一的配置问题

/**
 * 员工信息
 *
 */
public class Emp {
    private int id;
    private String name;
    private float salary;
    private Date startDate;
    private Dept dept;

    //setters and getters
}

 

/**
 * 部门信息
 *
 */
public class Dept {
    private int id;
    private String name;
    private Set<Emp> emps;

    //setters and getters
}

 

下面是员工对应部门的配置：

 

<!-- Emp结果映射 -->
<resultMap type="Emp" id="empMap">
    <id property="id" column="empno" />
    <result property="name" column="ename" />
    <result property="salary" column="sal" />
    <result property="startDate" column="startDate" javaType="java.util.Date" />
    <!-- 多对一映射 -->
    <association property="dept" column="deptno" select="getDeptById"/>
</resultMap>

<!-- empMap用来获取Dept -->
<select id="getDeptById" parameterType="Integer" resultType="Dept">
    select deptno id,dname name from dept where deptno = #{id}
</select>

 

测试使用的数据库表结构：

create table DEPT
(
  DEPTNO NUMBER(10) not null,
  DNAME  VARCHAR2(20)
)

create table EMP
(
  EMPNO     NUMBER(10) not null,
  ENAME     VARCHAR2(20),
  SAL       NUMBER(6,2),
  STARTDATE DATE,
  DEPTNO    NUMBER(10)
)