单个实体关联查询：
? <resultMap id="transactionResultMapEmpower" type="com.xxxx.dal.dataobject.transaction.TransactionDO2" >
? ? ? ? <id property="id" column="id"/>
? ? ? ? <result ?property="traderUnitsName" column="trader_units_name"/>
? ? ? ? <result ?property="transactionAmount" column="transaction_amount"/>
? ? ? ? <result ?property="transactionDate" column="transaction_date"/>
? ? ? ? <result ?property="transactionStatus" column="transaction_status"/>
? ? ? ? <result ?property="transactionApplicationTime" column="transaction_application_time"/>
? ? ? ? <result ?property="transactionApplicationUnitName" column="transaction_application_unit_name"/>
? ? ? ? <result property="valueEvaluationType" column="value_evaluation_type"/>
? ? ? ? <result column="result_id" jdbcType="INTEGER" property="resultId" />
? ? ? ? <association property="resultinfoDO"?
? ? ? ? ?javaType="com.xxxx.dal.dataobject.resultinfo.ResultinfoDO"?
? ? ? ? ?column="result_id" ?
? ? ? ? ?? ??? ?select="com.ixxxx.dal.mysql.resultinfo.ResultinfoMapper.selectById"?
? ? ? ? ?? ??? ?fetchType="eager" >
? ? ? ? </association>
? ? ? ??
? ? </resultMap>
设置mybatis二级缓存策略：
添加一个属性fetchType="eager"?(急加载)
集合查询：
<collection property="roles" ofType="Role"
????????select="com.jd.wms.mapper.RoleMapper.selectRolesByEmployeeId" column="id">
</collection>