JAVA获取树形结构

package com.nnmzkj.common.dto;

import lombok.Data;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

@Data
public class TreeParamDto implements Serializable {

    private static final long serialVersionUID = -7692266106281926159L;
    private Long id;

    private String name;

    private Long parentId;

    private Long menuId; //冗余字段

    private Integer isParent;

    private List<TreeParamDto> children ;
}

/////////////////
package com.nnmzkj.common.utils;

import com.nnmzkj.common.dto.BaseTreeGrid;
import com.nnmzkj.common.dto.TreeParamDto;
import com.nnmzkj.sys.model.SysMenuEntity;
import com.nnmzkj.sys.model.SysOrgEntity;
import org.springframework.stereotype.Component;

import java.util.ArrayList;
import java.util.List;

@Component
public class TreeUtils {

    /**
     * 真*树形结构
     * @param myId
     * @param list
     * @param <T>
     * @return
     */
    public  static <T extends TreeParamDto> List<T> getTreeArray(Long myId,List<T> list){
        List<T> result = new ArrayList<T>();
        List<T> childList = getChild(myId, list);
        if (childList.size() >0){
            for (T t : childList) {
                List<T> treeArray = getTreeArray(t.getId(), list);
                if(t.getChildren() == null) {
                    t.setChildren(new ArrayList<TreeParamDto>());
                }
                    for (T t1 : treeArray) {
                        t.getChildren().add(t1);
                    }
                result.add(t);
            }
        }
        return result;
    }

    public  static <T extends TreeParamDto> List<T> selectTree(Long myId,List<T> list,List<T> result,String str){
        List<T> childList = getChild(myId, list);
        if (childList.size() >0){
            if (myId >0){
                str = "|----" + str;
            }
            for (T t : childList) {
                t.setName(str+t.getName());
                result.add(t);
                result = selectTree(t.getId(), list,result,str);
            }
            return  result;
        }
        return result;
    }

    /**
     * 获取子集
     * @param list
     * @param <T>
     * @return
     */
    public  static <T extends TreeParamDto> List<T> getChild(Long myId,List<T> list){
        List<T> result = new ArrayList<T>();
        if (!StringUtil.isNullOrEmpty(list) && list.size() >0){
            for (T t : list) {
                if (t.getParentId().equals(myId)){
                    result.add(t);
                }
            }
        }
        return result;
    }

    public static List<SysOrgEntity> selectOrg(List<SysOrgEntity> list){
        list = getTreeList(list);
        for (SysOrgEntity sysOrg : list) {
            String str ="";
            Byte level = sysOrg.getLevel();
            if (level != 0){
                for (int i=0 ;i<sysOrg.getLevel();i++){
                    str = str + "|----";
                }
            }
            sysOrg.setName(str+sysOrg.getName());
        }
        return list;
    }

    /**
     * 使列表树结构排序
     * @param allList
     * @return
     */
    public static List<SysOrgEntity> getTreeList(List<SysOrgEntity> allList){
        List<SysOrgEntity> rootList = getTreeRootList(0,allList);
        List<SysOrgEntity> list = new ArrayList<SysOrgEntity>();
        for (SysOrgEntity entity : rootList) {
            list.addAll(getChildList(entity,allList));
        }
        return list ;
    }

    /**
     * 获取所有子机构
     * @param parent       父机构
     * @param allList   所有列表
     * @return
     */
    public static List<SysOrgEntity> getChildList(SysOrgEntity parent,List<SysOrgEntity> allList){
        //存放子机构的集合
        ArrayList<SysOrgEntity> listChild = new ArrayList<SysOrgEntity>();
        listChild.add(parent);
        for (SysOrgEntity entity : allList) {
            if(entity.getParentId().equals(parent.getOrgId())) {
                listChild.addAll(getChildList(entity, allList)) ;
            }
        }
        return listChild ;
    }

    /**
     * 获取根机构集合
     * @param rootLevel    根机构等级
     * @param allList
     * @return
     */
    public static List<SysOrgEntity> getTreeRootList(int rootLevel,List<SysOrgEntity> allList){
        if(rootLevel>=5){
            return null;
        }
        List<SysOrgEntity> rootList = new ArrayList<SysOrgEntity>();
        for (SysOrgEntity entity : allList) {
            if(entity.getLevel()==rootLevel){
                rootList.add(entity);
            }
        }
        if(rootList.size()>0){
            return rootList ;
        }else{
            rootList = getTreeRootList(rootLevel+1,allList);
        }
        return rootList;
    }
}