后端返回树结构

出参结构

@Getter
@Setter
public class TreeResponse implements Serializable {
    // 主键
    private Long id;
    // 父级节点
    private Long parentId;
    // 层级
    private Byte layer;
    // 编码
    private String docCode;
    // 名称
    private String docName;
    // 子节点
    private List<TreeResponse> childNode;
}

方案一：生撸

public Result<List<TreeResponse>> listTreeData(String code) {
    // 查询全量数据
    List<TreeResponse> tempTreeResponse = new ArrayList<>();
    // 树节点转换
    return Result.success(convertTreeStructure(tempTreeResponse));
}

/**
 * 树形转换
 *
 * @param tempTreeResponse 档案信息
 * @return 档案信息-树
 */
private List<TreeResponse> convertTreeStructure(List<TreeResponse> tempTreeResponse) {
    // 获取第一层级
	List<TreeResponse> treeResponse = tempTreeResponse.stream()
			.filter(value -> Objects.isNull(value.getParentId()))
			.collect(Collectors.toList());
    // 获取非第一层级数据，并以父级ID进行分组
	Map<Long, List<TreeResponse>> notFirstLayerData = tempTreeResponse.stream()
			.filter(value -> Objects.nonNull(value.getParentId()))
			.collect(Collectors.groupingBy(TreeResponse::getParentId));
	treeResponse.forEach(data -> setChildData(data, notFirstLayerData));
	return treeResponse;
}

/**
 * 设置子节点
 *
 * @param parentInfo        父节点信息
 * @param notFirstLayerData 非首节点信息
 */
private void setChildData(TreeResponse parentInfo, Map<Long, List<TreeResponse>> notFirstLayerData) {
	List<TreeResponse> childData = notFirstLayerData.get(parentInfo.getId());
	if (CollectionUtils.isNotEmpty(childData)) {
		parentInfo.setChildNode(childData);
		childData.forEach(data -> setChildData(data, notFirstLayerData));
	}
}

方案二：Hutool

//配置
TreeNodeConfig treeNodeConfig = new TreeNodeConfig();
// 自定义属性名 都要默认值的
treeNodeConfig.setWeightKey("order");
treeNodeConfig.setIdKey("rid");
// 最大递归深度
treeNodeConfig.setDeep(3);

//转换器 (含义:找出父节点为字符串零的所有子节点, 并递归查找对应的子节点, 深度最多为 3)
List<Tree<String>> treeNodes = TreeUtil.<TreeNode, String>build(nodeList, "0", treeNodeConfig,
		(treeNode, tree) -> {
			tree.setId(treeNode.getId());
			tree.setParentId(treeNode.getParentId());
			tree.setWeight(treeNode.getWeight());
			tree.setName(treeNode.getName());
			// 扩展属性 ...
			tree.putExtra("extraField", 666);
			tree.putExtra("other", new Object());
		});