1.实体类
1 class Company{
2 private String c_id ; //对应数据库中的PKEY
3 private String c_name ;
4 private String c_address ;
5 private String c_type ;
6 private Dept dept =new Dept();//记得new 不然xml文件会报null
7 private Role role =new Role();//记得new 不然xml文件会报null
8 .....
9 }
10 class Dept{
11 private String d_id ; //对应数据库中的PKEY
12 private String d_name ;
13 private String d_num ;
14 .....
15 }
16 class Role{
17 private String r_id ; //对应数据库中的PKEY
18 private String r_name ;
19 private String r_num ;
20 .....
21 }
22
2.xxMapper.xml中的Map写法
<resultMap ik="companyMap" type="com.ss.syf.domain.Company">
<id column="c_id" property="c_id"/>
<result column="c_name" property="c_name"/>
<result column="c_address" property="c_address"/>
<result column="c_type" property="c_type"/>
<collection property="dept" ofType="com.ss.syf.domain.Dept">
<id column="d_id" property="d_id"/>
<result column="d_name" property="d_name"/>
<result column="d_num" property="d_num"/>
</collection>
<collection property="role" ofType="com.ss.syf.domain.Role">
<id column="r_id" property="r_id"/>
<result column="r_name" property="r_name"/>
<result column="r_num" property="r_num"/>
</collection>
</resultMap>
springboot——Mapper.xml中的resultMap
原文：https://www.cnblogs.com/nana-qiu/p/11661093.html