Mybatis返回树形结构

    <resultMap id="orgTreeMap" type="com.ylz.api.vo.OrgVO">
        <result column="org_id" jdbcType="VARCHAR" property="orgId"/>
        <result column="org_name" jdbcType="VARCHAR" property="orgName"/>
        <result column="parent_id" jdbcType="VARCHAR" property="parentId"/>
        <collection column="org_id" property="children"  ofType="com.ylz.api.vo.OrgVO"  select="getOrgByParentId" >
        </collection>
    </resultMap>
    <select id="getOrgTree" parameterType="java.lang.String" resultMap="orgTreeMap">
        select o.org_id, o.org_name, o.parent_id
        from org_table@allcenter_db o
        where o.org_id = #{orgId}
    </select>
    <select id="getOrgByParentId" parameterType="java.lang.String" resultMap="orgTreeMap">
        select o.org_id, o.org_name, o.parent_id
        from org_table@allcenter_db o
        where o.parent_id = #{orgId}
    </select>

@JsonIgnoreProperties(ignoreUnknown = true)
public class OrgVO {
    private String orgId;
    private String orgName;
    private String parentId;//父机构id
    private List<OrgVO> children;
 }

    public String orgTree(OverviewPojo overviewPojo) {
        OrgVO orgVO = userMapper.selectOrgInfoByUserId(overviewPojo.getUserId());
        List<OrgVO> orgTree = orgMapper.getOrgTree(orgVO.getOrgId());
        return ReturnJsonFormatUntil.json(true, AnalysisJson.parseListWithGson(orgTree));
    }

public class 树型关系 {
    public static void main(String[] args) {
        //初始化数据
        NodeTree NodeTree1 = new NodeTree("xx1",1,-1);
        NodeTree NodeTree2 = new NodeTree("xx2",2,-1);
        NodeTree NodeTree3 = new NodeTree("xx3",3,-1);
        NodeTree NodeTree4 = new NodeTree("xx4",4,1);
        NodeTree NodeTree5 = new NodeTree("xx5",5,2);
        NodeTree NodeTree6 = new NodeTree("xx6",6,3);
        NodeTree NodeTree7 = new NodeTree("xx7",7,4);
        NodeTree NodeTree8 = new NodeTree("xx8",8,7);
        NodeTree NodeTree9 = new NodeTree("xx9",9,5);
        List<NodeTree> list = new ArrayList<>();
        list.add(NodeTree1);
        list.add(NodeTree2);
        list.add(NodeTree3);
        list.add(NodeTree4);
        list.add(NodeTree5);
        list.add(NodeTree6);
        list.add(NodeTree7);
        list.add(NodeTree8);
        list.add(NodeTree9);
        List<NodeTree> collect = list.stream()
                //找到所有最顶级的节点
                .filter(e -> e.pid.equals(-1))
                //查找顶级节点的所有子节点
                .map(e -> covert(e, list))
                .collect(Collectors.toList());
        System.out.println(collect);
    }
    /**
     * 返回当前节点的以及所有子节点
     * @param nodeTree 当前节点
     * @param nodeTreeList 所有节点
     * @return
     */
    public static NodeTree covert(NodeTree nodeTree, List<NodeTree> nodeTreeList) {
        List<NodeTree> children = nodeTreeList.stream()
                //过滤出当前节点的下一级子节点
                .filter(subNodeTree -> subNodeTree.getPid().equals(nodeTree.getId()))
                //递归查找
                .map(subNodeTree -> covert(subNodeTree, nodeTreeList)).collect(Collectors.toList());
        nodeTree.setChildren(children);
        return nodeTree;
    }
}
@Data
@NoArgsConstructor
class NodeTree {
    //名称
    String name;
    //id
    Integer id;
    //父id
    Integer pid;
    //子节点
    List<NodeTree> children;
    public NodeTree(String name, Integer id, Integer pid) {
        this.name = name;
        this.id = id;
        this.pid = pid;
    }
}