Java中递归构建树形结构的算法解读

public static void main(String[] args) {
    // todo 业务数据
    List<TreeVo> treeVoList = new ArrayList<>();

	// 处理父节点为空的情况
    treeVoList
            .stream()
            .filter(obj -> StringUtils.isBlank(obj.getPid()))
            .forEach(obj -> obj.setPid("-1"));

	// 根据父节点分组
    Map<String, List<TreeVo>> treeCatch = treeVoList.stream()
            .collect(Collectors.groupingBy(TreeVo::getPid));

    // 递归查询子节点，写入当前数据
    treeVoList = findChildren(treeCatch, "-1");

    // 打印
    for (TreeVo treeVo : treeVoList) {
        System.out.println(JacksonUtil.bean2json(treeVo));
    }
}

private static List<TreeVo> findChildren(Map<String, List<TreeVo>> treeCatch, String parentId) {
    List<TreeVo> children = treeCatch.getOrDefault(parentId, new ArrayList<>());
    for (TreeVo treeVo : children) {
        List<TreeVo> subChildren = findChildren(treeCatch, treeVo.getId());
        treeVo.getChildren().addAll(subChildren);
    }
    return children;
}



/**
 * 获取场地树RVO
 */
public class TreeVo {

    /**
     * ID
     */
    private String id;

    /**
     * 名称
     */
    private String name;
    
    /**
     * 父ID
     */
    private String pid;

    /**
     * 子级
     */
    private transient List<TreeVo> children;
	
	// 此处省略get\set
}