树工具备份

实体

public abstract class TreeNode {

    /**
     * 当前节点id
     */
    public abstract Long getNodeId();

    /**
     * 父级节点id
     */
    public abstract Long getNodePId();

    /**
     * 是否根节点
     */
    @Getter
    private Boolean rootNode;

    /**
     * 是否叶子节点
     **/
    @Getter
    private Boolean leafNode;

    /**
     * 子节点数据
     **/
    @Getter
    private List<TreeNode> children;

    /**
     * 设置子节点数据，设置为protected禁止外部调用
     **/
    public void setChildren(List<TreeNode> children) {
        this.children = children;
        this.rootNode = Objects.equals(getNodePId(), -1L);
        this.leafNode = children == null || children.isEmpty();
    }

}

工具类

public class TreeUtils {

    public static <T extends TreeNode> List<T> buildTree(List<T> nodes) {

        if (CollectionUtils.isEmpty(nodes)) {
            return Collections.emptyList();
        }
        Map<Long, List<TreeNode>> groups = nodes.stream().collect(Collectors.groupingBy(TreeNode::getNodePId));
        return nodes.stream().filter(Objects::nonNull).peek(pnd -> {
            List<TreeNode> ts = groups.get(pnd.getNodeId());
            pnd.setChildren(ts);
        }).filter(TreeNode::getRootNode).collect(Collectors.toList());

    }

    public static <T extends TreeNode> void findAll(List<T> result, TreeNode node, Long targetId) {

        if (node.getNodeId().equals(targetId) || node.getNodePId().equals(targetId)) {
            addAll(result, node);
        } else {
            if (!CollectionUtils.isEmpty(node.getChildren())) {
                for (TreeNode child : node.getChildren()) {
                    findAll(result, child, targetId);
                }
            }
        }

    }


    private static <T extends TreeNode> void addAll(List<T> result, TreeNode node) {
        result.add((T) node);
        if (!CollectionUtils.isEmpty(node.getChildren())) {
            for (TreeNode child : node.getChildren()) {
                addAll(result, child);
            }
        }
    }

}