构建一颗普通树

场景：

权限管理资源分级别：

一级资源（部门管理，项目管理）

二级资源（列表，详情，编辑，删除，增加）

三级资源（过滤条件，展示范围，深度）

也可能有更多级别的资源，现在需要构建一个普通树来存放。

node类

package com.haizhi.gap.sys.auth.model.vo;


import com.haizhi.gap.sys.auth.model.po.SysResourcePo;
import io.swagger.annotations.ApiModelProperty;

import java.util.LinkedList;

/**
 * Created by tanghaiyang on 2019/1/8.
 */
public class SysResourceNodeVo {

    @ApiModelProperty(value = "资源ID", example = "0")
    public Long id;

    @ApiModelProperty(value = "用户父ID", example = "8")
    public int parentId;

    @ApiModelProperty(value = "资源名", example = "列表")
    public String name;

    @ApiModelProperty(value = "资源url", example = "http://xxxx:xx/api/xx")
    public String url;

    @ApiModelProperty(value = "资源级别", example = "一级资源")
    public String remark;

    public LinkedList<SysResourceNodeVo> childList;

    public SysResourceNodeVo(Long id, int parentId, String name, String remark) {
        this.id = id;
        this.parentId = parentId;
        this.name = name;
        this.remark = remark;
    }

    public SysResourceNodeVo(SysResourcePo po) {
        this.id = po.getId();
        this.parentId = po.getParentId();
        this.name = po.getName();
        this.remark = po.getRemark();
    }

    public boolean add(SysResourceNodeVo sysResourceNodeVo){
        if (childList == null) {
            childList = new LinkedList<>();
        }
        return childList.add(sysResourceNodeVo);
    }

}

Tree类

package com.haizhi.gap.sys.auth.model.vo;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.serializer.SerializerFeature;

import java.util.Objects;

/**
 * Created by tanghaiyang on 2019/1/8.
 */
public class SysResourceTreeVo {

    private SysResourceNodeVo root;

    public SysResourceTreeVo() {
        root = null;
    }

    public void insertNode(SysResourceNodeVo childSysResourceNodeVo) {
        if (root == null) {
            root = new SysResourceNodeVo(0L, 0, "root", "根节点");
        }
        SysResourceNodeVo currentSysResourceNodeVo = root;
        addNode(currentSysResourceNodeVo, childSysResourceNodeVo);
    }

    private boolean addNode(SysResourceNodeVo currentSysResourceNodeVo, SysResourceNodeVo sysResourceNodeVo) {
        if( currentSysResourceNodeVo.id == sysResourceNodeVo.parentId ){
            currentSysResourceNodeVo.add(sysResourceNodeVo);
            System.out.println("add sysResourceNodeVo: " + sysResourceNodeVo.id);
            return true;
        }

        if (Objects.nonNull(currentSysResourceNodeVo.childList)){
            for(int i = 0; i< currentSysResourceNodeVo.childList.size(); i++){
                System.out.println(currentSysResourceNodeVo.childList);
                SysResourceNodeVo child  = currentSysResourceNodeVo.childList.get(i);
                addNode(child, sysResourceNodeVo);
            }
        }

        return false;
    }


    public String toString(){
        return JSON.toJSONString(root, SerializerFeature.PrettyFormat);
    }
}

测试用例：

package com.haizhi.gap.sys.auth.model.vo;

/**
 * Created by tanghaiyang on 2019/1/8.
 */
public class ResourceTreeTest {

    public static void main(String[] args) {

        SysResourceNodeVo sysResourceNodeVo1 = new SysResourceNodeVo(11L, 0, "dddd", "一级资源");
        SysResourceNodeVo sysResourceNodeVo2 = new SysResourceNodeVo(12L, 11, "dddd", "一级资源");
        SysResourceNodeVo sysResourceNodeVo3 = new SysResourceNodeVo(13L, 12, "dddd", "二级资源");
        SysResourceNodeVo sysResourceNodeVo4 = new SysResourceNodeVo(14L, 12, "dddd", "二级资源");
        SysResourceNodeVo sysResourceNodeVo5 = new SysResourceNodeVo(15L, 14, "dddd", "三级资源");

        SysResourceTreeVo resourceTree = new SysResourceTreeVo();

        resourceTree.insertNode(sysResourceNodeVo1);
        resourceTree.insertNode(sysResourceNodeVo2);
        resourceTree.insertNode(sysResourceNodeVo3);
        resourceTree.insertNode(sysResourceNodeVo4);
        resourceTree.insertNode(sysResourceNodeVo5);

        System.out.println(resourceTree.toString());
    }


}