递归构建树状结构

Dear 丶 2024-04-17 21:52 73阅读 0赞

**构建树状结构Demo所需数据库脚本：**  
[**数据库脚本**][Link 1]

**数据结构如下：**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1eGllbGVh_size_16_color_FFFFFF_t_70]

**核心逻辑代码如下：**

@Service
    public class AreaServiceImpl extends ServiceImpl<AreaMapper, TArea> implements AreaService {
    
        @Autowired
        private AreaMapper dao;
    
        @Override
        public List<TArea> tree() {
            QueryWrapper<TArea> queryWrapper = Wrappers.query();
            // 查询所有节点
            List<TArea> nodes = dao.selectList(queryWrapper);
            // 生成树结构
            List<TArea> tree = buildTree(nodes);
            return tree;
        }
    
        private List<TArea> buildTree(List<TArea> nodes) {
            List<TArea> tree = new ArrayList<TArea>();
            for (TArea node : nodes) {
                if (node.getParentId() == 0) {// 根节点
                    tree.add(node);
                    build(node, nodes);// 递归
                }
            }
            return tree;
        }
    
        /**
         * 递归，构建树状结构
         * @param node
         * @param nodes
         */
        private void build(TArea node, List<TArea> nodes) {
            List<TArea> children = getChildren(node, nodes);
            if (!children.isEmpty()) {
                node.setChildren(children);
                for (TArea child : children) {
                    build(child, nodes);
                }
            }
        }
    
        /**
         * 构建子级数据
         * @param node
         * @param nodes
         * @return
         */
        private List<TArea> getChildren(TArea node, List<TArea> nodes) {
            List<TArea> children = new ArrayList<TArea>();
            for (TArea org : nodes) {
                Long pId = org.getParentId();
                if (node.getId().equals(pId)) {
                    children.add(org);
                }
            }
            return children;
        }
    
    }

**测试结果如下：**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1eGllbGVh_size_16_color_FFFFFF_t_70 1]  
**前端采用Vue-Ztree-2.0实现：**  
![在这里插入图片描述][20190901203715866.png]

[**Demo代码（包含前后端）**][Demo]

[Link 1]: https://download.csdn.net/download/yuxielea/11647258
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1eGllbGVh_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/78441396ff7c4fcda8cb3370b17caec8.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1eGllbGVh_size_16_color_FFFFFF_t_70 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/4ed8550ac4784571aaeb7d91823df891.png
[20190901203715866.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/b49314356de54784b4a276e902005850.png
[Demo]: https://download.csdn.net/download/yuxielea/11647281