中间表
中间表存储了表 A 的 id 和表 B 的 id，除此之外还存储了自身需要的字段，如创建时间、id。
xml
很简单，通过多个子查询获取数据就可以了，将中间表的字段传递给子查询的 column，子查询获取这个参数进行 where 条件查询。
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.bleuon.mapper.CollectFlowchartMapper">
<resultMap id="mapOfFindAll" type="com.bleuon.entity.dto.CollectFlowchart">
<id column="id" property="id"/>
<association property="flowchart" javaType="com.bleuon.entity.dto.CollectFlowchart$Flowchart"
select="findFlowchartById" column="flowchart_id"/>
<association property="user" javaType="com.bleuon.entity.dto.CollectFlowchart$User" select="findUserById"
column="belong_uid"/>
</resultMap>
<select id="findAll" resultMap="mapOfFindAll" resultType="com.bleuon.entity.dto.CollectFlowchart">
select *
from co_collect_flowchart
where collect_uid = #{uid};
</select>
<select id="findFlowchartById" resultType="com.bleuon.entity.dto.CollectFlowchart$Flowchart">
select *
from t_flowcharts
where id = #{id}
</select>
<select id="findUserById" resultType="com.bleuon.entity.dto.CollectFlowchart$User">
select id, avatar, username
from t_users
where id = #{id};
</select>
</mapper>