Java代码实现封装多级树结构对象

@Data
@AllArgsConstructor
public class TreeDto {
    private String id;
    private String name;
    private String pid;
    private String isParent;
    private List<TreeDto> childTreeDto;

}

public class TreeToolUtils {
    private List<TreeDto> rootList; //根节点对象存放到这里

    private List<TreeDto> bodyList; //其他节点存放到这里，可以包含根节点

    public TreeToolUtils(List<TreeDto> rootList, List<TreeDto> bodyList) {
        this.rootList = rootList;
        this.bodyList = bodyList;
    }

    public List<TreeDto> getTree(){   //调用的方法入口
        if(bodyList != null && !bodyList.isEmpty()){
            //声明一个map，用来过滤已操作过的数据
            Map<String,String> map = Maps.newHashMapWithExpectedSize(bodyList.size());
            rootList.forEach(beanTree -> getChild(beanTree,map));
            return rootList;
        }
        return null;
    }

    public void getChild(TreeDto treeDto,Map<String,String> map){
        List<TreeDto> childList = Lists.newArrayList();
        bodyList.stream()
                .filter(c -> !map.containsKey(c.getId()))
                .filter(c ->c.getPid().equals(treeDto.getId()))
                .forEach(c ->{
                    map.put(c.getId(),c.getPid());
                    getChild(c,map);
                    childList.add(c);
                });
        treeDto.setChildTreeDto(childList);

    }
}

TreeDto treeDto = new TreeDto("1", "总店", "null", "true",null);
    TreeDto treeDto1 = new TreeDto("2", "市分店", "1", "true",null);
    TreeDto treeDto2 = new TreeDto("3", "县分店", "2", "true",null);
    TreeDto treeDto3 = new TreeDto("710", "店长", "3", "true",null);
    TreeDto treeDto4= new TreeDto("713", "财务部", "3", "true",null);
    TreeDto treeDto5 = new TreeDto("20032", "后勤部", "3", "true",null);
    TreeDto treeDto6 = new TreeDto("1909", "小王", "710", "false",null);
    TreeDto treeDto7= new TreeDto("1974", "小张", "713", "false",null);
    TreeDto treeDto8 = new TreeDto("388187", "佳佳", "20032", "false",null);
    TreeDto treeDto9 = new TreeDto("1949", "阿达", "20032", "false",null);
    ArrayList<TreeDto> rootList = new ArrayList<>();//根节点
    ArrayList<TreeDto> bodyList = new ArrayList<>();//子节点
    rootList.add(treeDto);
    bodyList.add(treeDto1);
    bodyList.add(treeDto2);
    bodyList.add(treeDto3);
    bodyList.add(treeDto4);
    bodyList.add(treeDto5);
    bodyList.add(treeDto6);
    bodyList.add(treeDto7);
    bodyList.add(treeDto8);
    bodyList.add(treeDto9);
    TreeToolUtils utils =  new TreeToolUtils(rootList,bodyList);
    List<TreeDto> result =  utils.getTree();
    String jsonString = JSONObject.toJSONString(result.get(0));
    System.out.println(jsonString);
}