mybatis 一对一关联对象查询

            <select id="getClassInfo" parameterType="int" resultMap="ClassResultMap">
                select * from class c,teacher t where c.teacher_id = t.t_id and c.c_id = #{id}
            </select>
            <!-- 解决字段名属性名不一致问题 -->
            <resultMap type="Classes" id="ClassResultMap">
                <id property="id" column="c_id"/>
                <result property="name" column="c_name"/>
                <!-- 一对一关联查询 -->
                <association property="teacher" column="teacher_id" javaType="Teacher">
                    <id property="id" column="t_id"/>
                    <result property="name" column="t_name"/>
                </association>
            </resultMap>

 

 

 <select id="getClassInfo2" parameterType="int" resultMap="ClassResultMap2" >
        select * from class where c_id = #{id}
    </select>

    <!-- 解决字段名属性名不一致问题 -->
    <resultMap type="Classes" id="ClassResultMap2">
        <id property="id" column="c_id"/>
        <result property="name" column="c_name"/>
        <association property="teacher" column="teacher_id"
                    javaType="Teacher" select="getTeacher">
        </association>
    </resultMap>

    <select id="getTeacher" parameterType="int" resultType="Teacher">
        select t_id id,t_name name from teacher where t_id=#{id}
    </select>