Java：封装树结构

实体类

public class DictTreeselectVO {private String value;private String label;/*** 节点*/private String parentId;private List<DictTreeselectVO> children = new ArrayList<DictTreeselectVO>();public String getValue() {return value;}public void setValue(String value) {this.value = value;}public String getLabel() {return label;}public void setLabel(String label) {this.label = label;}public String getParentId() {return parentId;}public void setParentId(String parentId) {this.parentId = parentId;}public List<DictTreeselectVO> getChildren() {return children;}public void setChildren(List<DictTreeselectVO> children) {this.children = children;}
}

返回结果

public class TreeSelectT implements Serializable
{private static final long serialVersionUID = 1L;/** 节点ID */private String id;/** 节点名称 */private String label;/** 子节点 */@JsonInclude(JsonInclude.Include.NON_EMPTY)private List<TreeSelectT> children;public TreeSelectT(){}public TreeSelectT(DictTreeselectVO dictTreeselectVO){this.id = dictTreeselectVO.getValue();this.label = dictTreeselectVO.getLabel();this.children = dictTreeselectVO.getChildren().stream().map(TreeSelectT::new).collect(Collectors.toList());}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getLabel() {return label;}public void setLabel(String label) {this.label = label;}public List<TreeSelectT> getChildren() {return children;}public void setChildren(List<TreeSelectT> children) {this.children = children;}
}

工具类

/**
* 创建树结构
* @param treeselectList
* @return
*/
public static List<TreeSelectT> buildTreeSelect(List<DictTreeselectVO> treeselectList){List<DictTreeselectVO> treeselectVOList = buildDictTreeselect(treeselectList);return treeselectVOList.stream().map(TreeSelectT::new).collect(Collectors.toList());
}/**
* 构建前端所需要树结构
* @param treeselectList
* @return
*/
private static List<DictTreeselectVO> buildDictTreeselect(List<DictTreeselectVO> treeselectList){List<DictTreeselectVO> returnList = new ArrayList<DictTreeselectVO>();List<String> tempList = treeselectList.stream().map(DictTreeselectVO::getValue).collect(Collectors.toList());for (DictTreeselectVO dictTreeselectVO : treeselectList) {// 如果是顶级节点, 遍历该父节点的所有子节点if (!tempList.contains(dictTreeselectVO.getParentId())) {recursionFn(treeselectList, dictTreeselectVO);returnList.add(dictTreeselectVO);}}if (returnList.isEmpty()){returnList = treeselectList;}return returnList;
}/*** 递归列表* @param list* @param t*/
private static void recursionFn (List<DictTreeselectVO> list, DictTreeselectVO t){// 得到子节点列表List<DictTreeselectVO> childList = getChildList(list, t);t.setChildren(childList);for (DictTreeselectVO tChild : childList) {if (hasChild(list, tChild)){recursionFn(list, tChild);}}
}/*** 得到子节点列表* @param list* @param t* @return*/
private static List<DictTreeselectVO> getChildList(List<DictTreeselectVO> list, DictTreeselectVO t)
{List<DictTreeselectVO> tlist = new ArrayList<DictTreeselectVO>();Iterator<DictTreeselectVO> it = list.iterator();while (it.hasNext()){DictTreeselectVO n = (DictTreeselectVO) it.next();if (StringUtils.isNotNull(n.getParentId()) && n.getParentId().equals(t.getValue())){tlist.add(n);}}return tlist;
}/*** 判断是否有子节点*/
private static boolean hasChild(List<DictTreeselectVO> list, DictTreeselectVO t){return getChildList(list, t).size() > 0;
}