在磁盘上存储结构树

Question

我有以下结构：

type Post struct {
  Id    int
  Name  string
  Text  string
  Posts []Post
}

要添加一些数据，我执行以下操作：

var posts []Post

posts = append(posts, Post{Id: 0, Name: "a", Text: "b"})
posts[0].Posts = append(posts[0].Posts, Post{Id: 1, Name: "c", Text: "d"})

posts = append(posts, Post{Id: 2, Name: "e", Text: "f"})
posts[0].Posts = append(posts[0].Posts, Post{Id: 3, Name: "h", Text: "d"})

如何有效地将这个结构树存储在磁盘上？我正在寻找可以在没有服务器的情况下使用的东西（比如 SQLite）。我希望能够搜索Id 2 或3，分别返回带有Id 2 或3 的整个结构。另外，我希望能够更新单个结构 f.e. Id 2.

另外，用Id作为地图的key，使用地图会更好吗？

Answer 1

使用 encoding/gob 将二进制数据放入文件中或再次取出

import (
    "bufio"
    "encoding/gob"
    "fmt"
    "os"
)

type Post struct {
    Id    int
    Name  string
    Text  string
    Posts []Post
}

func main() {

    var posts []Post

    posts = append(posts, Post{Id: 0, Name: "a", Text: "b"})
    posts[0].Posts = append(posts[0].Posts, Post{Id: 1, Name: "c", Text: "d"})

    posts = append(posts, Post{Id: 2, Name: "e", Text: "f"})
    posts[0].Posts = append(posts[0].Posts, Post{Id: 3, Name: "h", Text: "d"})
    fmt.Printf("%v\n", posts)

    path := "post.gob"

    // write
    out, err1 := os.Create(path)
    if err1 != nil {
        fmt.Printf("File write error: %v\n", err1)
        os.Exit(1)
    }
    w := bufio.NewWriter(out)
    enc := gob.NewEncoder(w)
    enc.Encode(posts)
    w.Flush()
    out.Close()

    // read
    b := make([]Post, 10)
    in, err2 := os.Open(path)
    if err2 != nil {
        fmt.Printf("File read error: %v\n", err2)
        os.Exit(1)
    }
    r := bufio.NewReader(in)
    dec := gob.NewDecoder(r)
    dec.Decode(&b)

    fmt.Printf("%v\n", b)

}