逆向递归，给一个完整的树，找对应的部门树

递归找到树 找到部门 树

构建一棵树 很简单，只要有parentId，很简单递归 就能构建好这棵树，今天来讲 怎么样 递归从树中 找到这个 对应 id 的树，比如传入 部门id 找到 这个部门树，逆向递归。

/**
     * 获取用户部门树
     * @param treeList
     * @return
     */
    private Tree<Long> getUserDeptTree(List<Tree<Long>> treeList,Long deptId){
        if(!CollectionUtils.isEmpty(treeList)) {
            for (int i = 0; i < treeList.size(); i++) {
                Tree<Long> tree = treeList.get(i);
                List<Tree<Long>> children = tree.getChildren();
                if (Objects.equals(tree.getId(), deptId) && !CollectionUtils.isEmpty(children)) {
                    return tree;
                }
                Tree<Long> buildUserDeptTree = getBuildUserDeptTree(children, deptId);
                if (!CollectionUtils.isEmpty(buildUserDeptTree)) {
                    return buildUserDeptTree;
                }
            }

        }
        return new Tree<>();
    }
    

    /**
     * 递归找到部门树
     * @param children
     * @param deptId
     * @return
     */
    private Tree<Long> getBuildUserDeptTree(List<Tree<Long>> children,Long deptId){
        Tree<Long> result =  new Tree<>();
        if(!CollectionUtils.isEmpty(children)){
            for (int i = 0; i < children.size(); i++) {
                Tree<Long> tree = children.get(i);
                List<Tree<Long>> childrenTree = tree.getChildren();
                if (Objects.equals(tree.getId(), deptId) && !CollectionUtils.isEmpty(children)) {
                    return tree;
                }
                Tree<Long> userDeptTree = getBuildUserDeptTree(childrenTree, deptId);
                if(!CollectionUtils.isEmpty(userDeptTree)){
                    return userDeptTree;
                }
            }
        }

        return result;
    }