java 树形结构通用封装类

小咪咪 2023-07-08 05:50 16阅读 0赞

/**
     * 基础树形结构数据服务类
     */
    @Service
    public class BaseTreeService {
    
        /**
         * 获取树结构数据
         * @return
         */
        public <T extends BaseTreeAO> ServiceResult<List<T>> listTreeNodes(List<T> allList) {
            ServiceResult<List<T>> ret = new ServiceResult<>();
            List<T> parentList = new ArrayList<>();//根节点
            List<T> classifyList = null;
            if ( !CollectionUtils.isEmpty(allList)) {
                classifyList = allList;
                for (T resource : allList) {
                    if (StringUtils.isEmpty(resource.getParentId())) {
                        parentList.add(resource);
                    }
                }
            }
            //返回的树形节点数据
            List<T> treeNodeList = new ArrayList<>();
            if (!CollectionUtils.isEmpty(parentList)) {
                for (T parent:parentList) {
                    //递归查询所有子节点
                    treeNodeList.add(recursiveTree(parent, classifyList));
                }
            }
            ret.setData(treeNodeList);
            ret.setSucceed(true);
            return ret;
        }
    
    
        /**
         * 递归算法解析成树形结构
         */
        public <T extends BaseTreeAO> T recursiveTree(T parentNode, List<T> classifyList) {
            List<T> childTreeNodes = getChildTree(parentNode.getId(), classifyList);
            if (!CollectionUtils.isEmpty(childTreeNodes)) {
                for (T child : childTreeNodes) {
                    T n = recursiveTree(child, classifyList);
                    parentNode.getChildren().add(n);
                }
            }
            return parentNode;
        }
    
        /**
         * 根据父节点ID获取所有子节点
         */
        public <T extends BaseTreeAO>  List<T> getChildTree(String parentId, List<T> classifyList) {
            List<T> childNodes = new ArrayList<>();
            if (!CollectionUtils.isEmpty(classifyList)) {
                for (T resource : classifyList) {
                    if (parentId.equals(resource.getParentId())) {
                        childNodes.add(resource);
                    }
                }
            }
            return childNodes;
        }
    
    
    }

//实体类，需要继承该实体类

public class BaseTreeAO<T> {
    
        private String id;
    
        private String parentId;
    
        /**
         * 子类
         */
        private List<T> children = new ArrayList<>();
    
        public String getId() {
            return id;
        }
    
        public void setId(String id) {
            this.id = id;
        }
    
        public String getParentId() {
            return parentId;
        }
    
        public void setParentId(String parentId) {
            this.parentId = parentId;
        }
    
        public List<T> getChildren() {
            return children;
        }
    
        public void setChildren(List<T> children) {
            this.children = children;
        }
    }