TreeUitls工具类Java树形结构数据处理(递归处理)

1、项目需求：

    从数据库从加载所有的菜单出来，菜单中有 

id,parentId,name字段

   希望能有一个工具帮我进行树形结构重组；

 

  实例类：

 

 

package com.ruoyi;

public class TreeNode {
    /**
     * 节点id
     */
    private String id;
    /**
     * 父节点 默认0为根节点
     */
    private String parentId;
    /**
     * 节点名称
     */
    private String name;
    /**
     * 是否有子节点
     */
    private boolean hasChild;

    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 String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public boolean isHasChild() {
        return hasChild;
    }

    public void setHasChild(boolean hasChild) {
        this.hasChild = hasChild;
    }

    public TreeNode(String id, String parentId, String name) {
        this.id = id;
        this.parentId = parentId;
        this.name = name;
    }
}

 

package com.ruoyi;


import com.alibaba.fastjson.JSONObject;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

public class TreeUtil {


    public static Map<String,Object> mapArray = new LinkedHashMap<String, Object>();

    public List<TreeNode> menuCommon;
    public List<Object> list = new ArrayList<Object>();

    public List<Object> treeMenu(List<TreeNode> menu){
        this.menuCommon = menu;
        for (TreeNode treeNode : menu) {
            Map<String,Object> mapArr = new LinkedHashMap<String, Object>();
            if(treeNode.getParentId().equals("0")){
                setTreeMap(mapArr,treeNode);
                list.add(mapArr);
            }
        }
        return list;
    }

    public List<?> menuChild(String id){
        List<Object> lists = new ArrayList<Object>();
        for(TreeNode a:menuCommon){
            Map<String,Object> childArray = new LinkedHashMap<String, Object>();
            if(a.getParentId() .equals(id)){
                setTreeMap(childArray,a);
                lists.add(childArray);
            }
        }
        return lists;
    }

    private void setTreeMap(Map<String,Object> mapArr,TreeNode treeNode){
        mapArr.put("id", treeNode.getId());
        mapArr.put("name", treeNode.getName());
        mapArr.put("parentId", treeNode.getParentId());
        List<?> childrens = menuChild(treeNode.getId());
        if(childrens.size()>0){
            mapArr.put("hasChild",true);
        }
        else{
            mapArr.put("hasChildren",false);
        }
        mapArr.put("childrens", menuChild(treeNode.getId()));
    }

    public  static void main(String[] args){

        List<TreeNode> treeNodeList = new ArrayList<>();
        TreeNode treeNode1 = new TreeNode("1","0","首页");
        TreeNode treeNode2 = new TreeNode("2","0","订单");
        TreeNode treeNode3 = new TreeNode("3","1","预约");
        TreeNode treeNode4 = new TreeNode("4","2","捐献");
        TreeNode treeNode5 = new TreeNode("5","4","我的订单");
        TreeNode treeNode6 = new TreeNode("6","5","个人中心");
        TreeNode treeNode7 = new TreeNode("7","6","个人中心2");
        TreeNode treeNode8 = new TreeNode("8","99","个人中心3");
        treeNodeList.add(treeNode1);
        treeNodeList.add(treeNode6);
        treeNodeList.add(treeNode5);
        treeNodeList.add(treeNode3);
        treeNodeList.add(treeNode4);
        treeNodeList.add(treeNode2);
        treeNodeList.add(treeNode7);
        treeNodeList.add(treeNode8);
        TreeUtil treeUtil = new TreeUtil();
        System.out.print(JSONObject.toJSONString(treeUtil.treeMenu(treeNodeList)));

    }


}