java遞歸生成組織結構樹工具類

public class TreeUtils {

    public static <T extends TreeNode> List<T> buildTreeNodes(List<T> listTreeNode, Long parentId) {

        List<T> distinctList = listTreeNode.stream().distinct().collect(Collectors.toList());

        List<T> listTreeNode_ = new ArrayList<>();

        for (T node : distinctList) {
            if (node.getParentId().equals(parentId)) {
                listTreeNode_.add(node);
            }
        }

        recursionMenuTree(listTreeNode, listTreeNode_);

        return listTreeNode_;
    }

    private static void recursionMenuTree(List<? extends TreeNode> listTreeNode, List<? extends TreeNode> listSubTreeNode) {
        for (TreeNode subNode : listSubTreeNode) {

            for (TreeNode node : listTreeNode) {
                if (subNode.getId().equals(node.getParentId())) {

                    if (CollectionUtils.isEmpty(subNode.getChildren())) {
                        subNode.setChildren(new ArrayList<>());
                    }

                    if (subNode.getChildren().contains(node)) {
                        continue;
                    }

                    subNode.getChildren().add(node);

                    recursionMenuTree(listTreeNode, subNode.getChildren());
                }
            }
        }
    }
}


public class TreeNode {

    protected Long id;

    @ApiModelProperty("父級節點")
    protected Long parentId;

    public List<TreeNode> children;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Long getParentId() {
        return parentId;
    }

    public void setParentId(Long parentId) {
        this.parentId = parentId;
    }

    public List<TreeNode> getChildren() {
        return children;
    }

    public void setChildren(List<TreeNode> children) {
        this.children = children;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        TreeNode treeNode = (TreeNode) o;

        return id != null ? id.equals(treeNode.id) : treeNode.id == null;
    }

    @Override
    public int hashCode() {
        return id != null ? id.hashCode() : 0;
    }
}