java 实现树形结构

实体父类

@Data
public class MenuTreeNode {

    @ApiModelProperty(value = "节点ID")
    private String node;

    @ApiModelProperty(value = "父节点ID")
    private String parentNode;

    @ApiModelProperty(value = "子标签")
    private List children;
}

实体子类

@Data
@NoArgsConstructor
@AllArgsConstructor
public class ResourcePoolDetailVO extends MenuTreeNode  {

    @ApiModelProperty(value = "流程编号")
    private String targetId;

    @ApiModelProperty(value = "科目名称")
    private String projectName;

    @ApiModelProperty(value = "对比期数据")
    private BigDecimal comparevalue;

    @ApiModelProperty(value = "指标数值")
    private BigDecimal indicatorValue;

    @ApiModelProperty(value = "手工调整项")
    private BigDecimal adjustValue;

    @ApiModelProperty(value = "调整后数值")
    private BigDecimal afterAdjustValue;

    @ApiModelProperty(value = "备注")
    private String remark;

    @ApiModelProperty(value = "节点ID")
    private String node;

    @ApiModelProperty(value = "父节点ID")
    private String parentNode;

    @ApiModelProperty(value = "创建时间，系统时间")
    private Date createDate;

    @ApiModelProperty(value = "子标签")
    private List children;

    public ResourcePoolDetailVO(ResourcePoolDetailDO srcData){
        if(srcData != null) {
            BeanUtils.copyProperties(srcData, this);
        }
    }
}

tree工具类

public class MenuTreeUtil {

    //建立树形结构
    public static  List buildTree(List detailDOS){
        List treeMenus =new  ArrayList<>();
        for(MenuTreeNode menuNode : getRootNode(detailDOS)) {
            menuNode=buildChildTree(menuNode,detailDOS);
            treeMenus.add(menuNode);
        }
        return treeMenus;
    }

    //递归，建立子树形结构
    private static MenuTreeNode buildChildTree(MenuTreeNode pNode, List detailDOS){
        List childMenus =new  ArrayList<>();
        for(MenuTreeNode menuNode : detailDOS) {
            if(menuNode.getParentNode().equals(pNode.getNode())) {
                childMenus.add(buildChildTree(menuNode,detailDOS));
            }
        }
        if(CollectionUtils.isNotEmpty(childMenus)){
            pNode.setChildren(childMenus);
        }
        return pNode;
    }

    //获取根节点
    private static List getRootNode(List detailDOS) {
        List rootMenuLists =new ArrayList<>();
        for(MenuTreeNode menuNode : detailDOS) {
            if(menuNode.getParentNode().equals("0")) {
                rootMenuLists.add(menuNode);
            }
        }
        return rootMenuLists;
    }

    
    public static  List convertToObjList(List detailDOS){

        List treeMenus =new  ArrayList<>();
        for (MenuTreeNode menuNode  : detailDOS) {
            if (menuNode.getChildren() != null) {
                treeMenus.add(menuNode);
                convertToObjList(menuNode.getChildren(), treeMenus);
            } else {
                treeMenus.add(menuNode);
            }
        }
        return treeMenus;
    }

    public static  void convertToObjList(List source ,
                                                                                         List outList){
        if(outList==null){
            outList = new ArrayList<>();
        }
        for (MenuTreeNode tTreeStructure : source) {
            if (tTreeStructure.getChildren() != null) {
                outList.add(tTreeStructure);
                convertToObjList(tTreeStructure.getChildren(), outList);
            } else {
                outList.add(tTreeStructure);
            }
        }
    }

}

将数据转换成树形结构

List detailVOS = new ArrayList<>();
List resultVOs = (List) MenuTreeUtil.buildTree(detailVOS);

将树形结构转换成扁平数据

List detailVOS = new ArrayList<>();
List detailVOS = (List) MenuTreeUtil.convertToObjList(detailVOS);