golang 无限级树状结构

package main
import(
    //"encoding/json"
    "encoding/json"
    "fmt"

)

type Datanode struct {
    Id int `json:"id"`
    PId int `json:"pid"`
    Name string `json:"name"`
    Child []*Datanode `json:"child"`
}
var Jsondata []byte  //存储json数据
func main(){
    Data := make([]Datanode, 0)  //存储所有初始化struct
    var a Datanode
    a.Id = 0
    a.PId = -1
    a.Name = "目录"
    Data = append(Data,a)

    a.Id = 1
    a.PId = 0
    a.Name = "一、水果"
    Data = append(Data,a)

    a.Id = 2
    a.PId = 1
    a.Name = "1.苹果"
    Data = append(Data,a)

    a.Id = 3
    a.PId = 1
    a.Name = "2.香蕉"
    Data = append(Data,a)


    a.Id = 4
    a.PId = 0
    a.Name = "二、蔬菜"
    Data = append(Data,a)


    a.Id = 5
    a.PId = 4
    a.Name = "1.芹菜"
    Data = append(Data,a)

    a.Id = 6
    a.PId = 4
    a.Name = "2.黄瓜"
    Data = append(Data,a)

    a.Id = 7
    a.PId = 6
    a.Name = "(1)黄瓜特点"
    Data = append(Data,a)

    a.Id = 8
    a.PId = 4
    a.Name = "3.西红柿"
    Data = append(Data,a)

    a.Id = 9
    a.PId = 0
    a.Name = "三、关系"
    Data = append(Data,a)

    var data []*Datanode
    data = make([]*Datanode,0)
    for i,_ := range Data{
        var a *Datanode
        a = &Data[i]
        data = append(data, a)
    }

    node := &Data[4] //父节点
    maketree(data,node)  //调用生成tree
    transformjson(node)  //转化为json
    jsontotree(Jsondata)  //json 转为struct
}

func maketree(Data []*Datanode, node *Datanode){        //参数为父节点，添加父节点的子节点指针切片
    childs,_ :=havechild(Data,node)      //判断节点是否有子节点并返回
        if childs != nil{
            fmt.Printf("\n")
            fmt.Println(*node)
            fmt.Println("子节点：")
            for _ ,v:= range childs{
                fmt.Println(*v)
            }                                   //打印

            node.Child = append(node.Child,childs[0:]...)    //添加子节点
            for _,v := range childs{            //查询子节点的子节点，并添加到子节点
                _, has := havechild(Data,v)
                if has {
                    maketree(Data, v)          //递归添加节点
                }
            }
        }
}

func havechild(Data []*Datanode, node *Datanode)(child []*Datanode,yes bool){
    for _,v := range Data{
        if v.PId == node.Id {
            child = append(child, v)
        }
    }
    if child != nil {
        yes = true
    }
    return
}

func transformjson(Data *Datanode){  //转为json

   Jsondata,_ = json.Marshal(Data)

        fmt.Println(string(Jsondata))
}

func jsontotree(jsondata []byte){  //json转struct
    var a Datanode
    err := json.Unmarshal(jsondata,&a)
    fmt.Println("22222222222222",string(jsondata))
    if err != nil{
        fmt.Println(err)
    }else{
        fmt.Println(a.Id,a.PId,a.Name)
        for _,v := range a.Child{
            fmt.Println(*v)
        }
    }
}