如何通过递归找父节点或子节点详解

article/2025/10/26 21:20:50

前言：如何通过递归去查询父节点或子节点，相信大家在平常肯定会遇到这样的需求，这一章我们就好好研究下如何用递归去找。

一、递归找父节点或子节点

二、创建一张表关系表保存上面的关系

三、递归查询父节点或子节点核心代码

四、演示查询父节点或子节点

一、递归找父节点或子节点

1、根据下图我如何去找下图inst的父节点：inst->crlim->cust->custTotal

2、根据下图我如何去找下图cust的子节点：cust->crlim->inst、cash、instCash

二、创建一张表关系表保存上面的关系

带着上面的疑问，我们首先先创建一张关系表，把这些关系都存到表中。

CREATE TABLE `limit_mesh` (`id` int NOT NULL AUTO_INCREMENT,`parent_node` varchar(255) COLLATE utf8mb4_bin DEFAULT NULL,`child_node` varchar(255) COLLATE utf8mb4_bin DEFAULT NULL,PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;INSERT INTO `limit_mesh`(`id`, `parent_node`, `child_node`) VALUES (1, 'crilm', 'inst');
INSERT INTO `limit_mesh`(`id`, `parent_node`, `child_node`) VALUES (2, 'crilm', 'cash');
INSERT INTO `limit_mesh`(`id`, `parent_node`, `child_node`) VALUES (3, 'crilm', 'instCash');
INSERT INTO `limit_mesh`(`id`, `parent_node`, `child_node`) VALUES (4, 'cust', 'crilm');
INSERT INTO `limit_mesh`(`id`, `parent_node`, `child_node`) VALUES (5, 'custTotal', 'cust');
INSERT INTO `limit_mesh`(`id`, `parent_node`, `child_node`) VALUES (6, 'cust', 'splmt');
INSERT INTO `limit_mesh`(`id`, `parent_node`, `child_node`) VALUES (7, 'splmt', 'byj');
INSERT INTO `limit_mesh`(`id`, `parent_node`, `child_node`) VALUES (8, 'splmt', 'ygj');

三、递归查询父节点或子节点核心代码

其他代码这里就不详细来写了，只写我们递归的核心代码。

递归查询父节点核心代码

    /*** 递归找父节点* @param nodeNo* @return*/public List<String> getLimitMeshParentList(String nodeNo) {List<String> parentList = new ArrayList<>();List<LimitMesh> limitMeshList = limitMeshService.getLimitMeshList();getParentNodeNo(limitMeshList,nodeNo,parentList);return parentList;}private List<String> getParentNodeNo(List<LimitMesh> limitMeshList,String nodeNo,List<String> parentList) {if (!parentList.contains(nodeNo)) {parentList.add(nodeNo);}List<String> parentRecursionList = getParentRecursionList(nodeNo,limitMeshList);if (CollectionUtils.isNotEmpty(parentRecursionList)) {if (!parentList.containsAll(parentRecursionList)) {parentList.addAll(parentRecursionList);}for (String str:parentRecursionList) {List<String> parentNodeNoList = getParentNodeNo(limitMeshList, str, parentList);if (!parentList.containsAll(parentNodeNoList)) {parentList.addAll(parentNodeNoList);}}}return parentList;}private List<String> getParentRecursionList(String nodeNo, List<LimitMesh> limitMeshList) {return limitMeshList.stream().filter(limitMesh -> limitMesh.getChildNode().equals(nodeNo)).map(limitMesh -> limitMesh.getParentNode()).collect(Collectors.toList());}

递归查询子节点核心代码

     /*** 递归找子节点* @param nodeNo* @return*/public List<String> getLimitMeshChildList(String nodeNo) {List<String> childList = new ArrayList<>();List<LimitMesh> limitMeshList = limitMeshService.getLimitMeshList();getChildNodeNo(limitMeshList,nodeNo,childList);return childList;}private List<String> getChildNodeNo(List<LimitMesh> limitMeshList, String nodeNo, List<String> childList) {if (!childList.contains(nodeNo)) {childList.add(nodeNo);}List<String> childRecursionList = getChildRecursionList(nodeNo,limitMeshList);if (CollectionUtils.isNotEmpty(childRecursionList)) {if (!childList.containsAll(childRecursionList)) {childList.addAll(childRecursionList);}for (String str:childRecursionList) {List<String> childNodeNoList = getChildNodeNo(limitMeshList, str, childList);if (!childList.containsAll(childNodeNoList)) {childList.addAll(childNodeNoList);}}}return childList;}private List<String> getChildRecursionList(String nodeNo, List<LimitMesh> limitMeshList) {return limitMeshList.stream().filter(limitMesh -> limitMesh.getParentNode().equals(nodeNo)).map(limitMesh -> limitMesh.getChildNode()).collect(Collectors.toList());}