添加注释： public static T extends BaseTreeNodeT ListT buildTreeListT nodes 构建父节点ID到子节点列表的映射关系 final MapString ListT childrenNodeGroup = CollectionUtilsemptyIfNullnodesstream fil

/**

• 构建树形结构的方法

• @param nodes 节点列表

• @param 节点类型，必须是BaseTreeNode的子类

• @return 构建好的树形结构 */ public static <T extends BaseTreeNode> List buildTree(List nodes) {

  // 构建父节点ID到子节点列表的映射关系 final Map<String, List> childrenNodeGroup = CollectionUtils.emptyIfNull(nodes).stream() .filter(l -> !l.checkIsRoot()) .collect(Collectors.groupingBy(BaseTreeNode::getParentId, Collectors.toList()));

  return CollectionUtils.emptyIfNull(nodes).stream() .peek(l -> l.setChildrens(MapUtils.getObject(childrenNodeGroup, l.getId()))) .filter(T::checkIsRoot) .collect(Collectors.toList());