json - 带有 Go Parse Json 响应的 Api 请求

Question

编写我的第一个 Go 应用程序 我正在学习进行基本的 api 调用并解析 json 响应。我很确定我没有正确转换我的类型，我的回答是

false
  0
 0

  0
 0 false
 0

如果我创建一些包含数据的数组，我可以获得该响应，但是当我将这个更复杂的 json 响应添加到混合中时，事情变得更加困惑，这让我非常肯定我没有正确转换。

这是我当前的代码，在尝试和更改内容以破坏内容并尝试解决问题之后。

package main

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net/http"
) 
    type Payload struct {
        results Data 
}

    type Data struct {
        poster_path string
        adult bool
        overview string
        release_date string
        genre_ids int
        id int
        original_title string
        original_language string
        title string
        backdrop_path string
        popularity float64
        vote_count int
        video bool
        vote_average float64
}


type poster_path map[string]string
type adult map[string]bool
type overview map[string]string
type release_date map[string]string
type genre_ids map[string]int
type id map[string]int
type original_title map[string]string
type original_language map[string]string
type title map[string]string
type backdrop_path map[string]string
type popularity map[string]float64
type vote_count map[string]int
type video map[string]bool
type vote_average map[string]float64

func main() {
      // http://image.tmdb.org/t/p/w185
      url := "https://api.themoviedb.org/3/movie/top_rated?api_key=####APIKEYHERE######"
      res, err := http.Get(url)
      if err != nil {
        panic(err)
      }
      defer res.Body.Close()

      body, err := ioutil.ReadAll(res.Body)
      if err != nil {
        panic(err)
      }
      var p Payload

      err = json.Unmarshal(body, &p)
      if err != nil {
        panic(err)
      }

      fmt.Println(
        p.results.poster_path, "\n", p.results.adult,
        p.results.overview, "\n", p.results.release_date,
        p.results.genre_ids, "\n", p.results.id,
        p.results.original_title, "\n", p.results.original_language,
        p.results.title, "\n", p.results.backdrop_path,
        p.results.popularity, "\n", p.results.vote_count,
        p.results.video, "\n", p.results.vote_average,
        )
}

这是 JSON 响应的样子，

{
    "page": 1,
    "results": [
        {
            "poster_path": "/lIv1QinFqz4dlp5U4lQ6HaiskOZ.jpg",
            "adult": false,
            "overview": "Under the direction of a ruthless instructor, a talented young drummer begins to pursue perfection at any cost, even his humanity.",
            "release_date": "2014-10-10",
            "genre_ids": [
                18,
                10402
            ],
            "id": 244786,
            "original_title": "Whiplash",
            "original_language": "en",
            "title": "Whiplash",
            "backdrop_path": "/6bbZ6XyvgfjhQwbplnUh1LSj1ky.jpg",
            "popularity": 9.685051,
            "vote_count": 1706,
            "video": false,
            "vote_average": 8.36
        }
}

一些让我印象深刻的事情，

当我尝试转换 float 时，我对从 float32 转换为 float64 感到困惑

json 响应中有一个数组，在尝试转换时会造成混淆，

"genre_ids": [
                36,
                18,
                53,
                10752
            ], 

Answer 1

是初学者常见的错误。由于语言设计，encoding/json 包只能解码为导出的字段。

来自encoding/json包裹:

To unmarshal JSON into a struct, Unmarshal matches incoming object keys to the keys used by Marshal (either the struct field name or its tag), preferring an exact match but also accepting a case-insensitive match. Unmarshal will only set exported fields of the struct.

要导出字段，只需使用名称的首字母大写即可。例如:

type Payload struct {
    Results Data 
}

代替

type Payload struct {
    results Data 
}