1、entity 中加入childrenMenu

@DATA
public class SysMenu implements Serializable {
    private static final long serialVersionUID = -85892554078912581L;
    /**
     * 编号
     */
    @TableId(type = IdType.ASSIGN_ID)
    private Long id;
    /**
     * 父级编号
     */
    private Long parentId;
    /**
     * 名称
     */
    private String name;


    private List<SysMenu> childrenMenu;

2、Mapper中修改resultMap ，加上collection

 <resultMap type="com.xiaoli.mcc.system.entity.SysMenu" id="SysMenuMap">
        <result property="id" column="id" jdbcType="INTEGER"/>
        <result property="parentId" column="parent_id" jdbcType="INTEGER"/>
        <result property="name" column="name" jdbcType="VARCHAR"/>
        <result property="type" column="type" jdbcType="INTEGER"/>
        <result property="sort" column="sort" jdbcType="INTEGER"/>
        <result property="href" column="href" jdbcType="VARCHAR"/>
        <result property="icon" column="icon" jdbcType="VARCHAR"/>
        <result property="category" column="category" jdbcType="INTEGER"/>
        <result property="permission" column="permission" jdbcType="VARCHAR"/>
        <result property="createTime" column="create_time" jdbcType="TIMESTAMP"/>
        <result property="updateTime" column="update_time" jdbcType="TIMESTAMP"/>
        <collection column="id" property="childrenMenu"  ofType="com.xiaoli.mcc.system.entity.SysMenu"  select="selectNodeByParentId" ></collection>
    </resultMap>

3、Mapper中加入connection的selectNodeByParentId,resultMap使用上面定义的resultMap。

<select id="selectNodeByParentId" parameterType="java.lang.Long" resultMap="SysMenuMap">
     select
         *
     from
         sys_menu
     where
         parent_id = #{id} 
     order by sort
 </select>

4、开始写自己的查询，只需将查出父id，resultMap使用上面定义的resultMap。

 <select id="selectWmsPcAllTreeNotOne" resultMap="SysMenuMap">
        select *
        from sys_menu
        where parent_id = 0 and category = 1 and type = 1
        order by sort
    </select>