由于go是静态强类型语言，不像JavaScript那样是动态语言，所以解析json的时候要先定义好解析后的结构体。
以获取豆瓣电影信息接口为例，地址如下：
http://api.douban.com/v2/movie/top250?start=0&count=2
应答结果：
{
"count": 2,
"start": 0,
"total": 250,
"subjects": [{
"rating": {
"max": 10,
"average": 9.6,
"stars": "50",
"min": 0
},
"genres": ["\u72af\u7f6a", "\u5267\u60c5"],
"title": "\u8096\u7533\u514b\u7684\u6551\u8d4e",
"casts": [{
"alt": "https:\/\/movie.douban.com\/celebrity\/1054521\/",
"avatars": {
"small": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p17525.webp",
"large": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p17525.webp",
"medium": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p17525.webp"
},
"name": "\u8482\u59c6\u00b7\u7f57\u5bbe\u65af",
"id": "1054521"
}, {
"alt": "https:\/\/movie.douban.com\/celebrity\/1054534\/",
"avatars": {
"small": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p34642.webp",
"large": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p34642.webp",
"medium": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p34642.webp"
},
"name": "\u6469\u6839\u00b7\u5f17\u91cc\u66fc",
"id": "1054534"
}, {
"alt": "https:\/\/movie.douban.com\/celebrity\/1041179\/",
"avatars": {
"small": "http://img3.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p5837.webp",
"large": "http://img3.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p5837.webp",
"medium": "http://img3.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p5837.webp"
},
"name": "\u9c8d\u52c3\u00b7\u5188\u987f",
"id": "1041179"
}],
"collect_count": 1819454,
"original_title": "The Shawshank Redemption",
"subtype": "movie",
"directors": [{
"alt": "https:\/\/movie.douban.com\/celebrity\/1047973\/",
"avatars": {
"small": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p230.webp",
"large": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p230.webp",
"medium": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p230.webp"
},
"name": "\u5f17\u5170\u514b\u00b7\u5fb7\u62c9\u90a6\u7279",
"id": "1047973"
}],
"year": "1994",
"images": {
"small": "http://img1.doubanio.com\/view\/photo\/s_ratio_poster\/public\/p480747492.webp",
"large": "http://img1.doubanio.com\/view\/photo\/s_ratio_poster\/public\/p480747492.webp",
"medium": "http://img1.doubanio.com\/view\/photo\/s_ratio_poster\/public\/p480747492.webp"
},
"alt": "https:\/\/movie.douban.com\/subject\/1292052\/",
"id": "1292052"
}, {
"rating": {
"max": 10,
"average": 9.6,
"stars": "50",
"min": 0
},
"genres": ["\u5267\u60c5", "\u7231\u60c5", "\u540c\u6027"],
"title": "\u9738\u738b\u522b\u59ec",
"casts": [{
"alt": "https:\/\/movie.douban.com\/celebrity\/1003494\/",
"avatars": {
"small": "http://img3.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p67.webp",
"large": "http://img3.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p67.webp",
"medium": "http://img3.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p67.webp"
},
"name": "\u5f20\u56fd\u8363",
"id": "1003494"
}, {
"alt": "https:\/\/movie.douban.com\/celebrity\/1050265\/",
"avatars": {
"small": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p46345.webp",
"large": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p46345.webp",
"medium": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p46345.webp"
},
"name": "\u5f20\u4e30\u6bc5",
"id": "1050265"
}, {
"alt": "https:\/\/movie.douban.com\/celebrity\/1035641\/",
"avatars": {
"small": "http://img3.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p1399268395.47.webp",
"large": "http://img3.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p1399268395.47.webp",
"medium": "http://img3.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p1399268395.47.webp"
},
"name": "\u5de9\u4fd0",
"id": "1035641"
}],
"collect_count": 1463014,
"original_title": "\u9738\u738b\u522b\u59ec",
"subtype": "movie",
"directors": [{
"alt": "https:\/\/movie.douban.com\/celebrity\/1023040\/",
"avatars": {
"small": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p1451727734.81.webp",
"large": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p1451727734.81.webp",
"medium": "http://img1.doubanio.com\/view\/celebrity\/s_ratio_celebrity\/public\/p1451727734.81.webp"
},
"name": "\u9648\u51ef\u6b4c",
"id": "1023040"
}],
"year": "1993",
"images": {
"small": "http://img1.doubanio.com\/view\/photo\/s_ratio_poster\/public\/p1910813120.webp",
"large": "http://img1.doubanio.com\/view\/photo\/s_ratio_poster\/public\/p1910813120.webp",
"medium": "http://img1.doubanio.com\/view\/photo\/s_ratio_poster\/public\/p1910813120.webp"
},
"alt": "https:\/\/movie.douban.com\/subject\/1291546\/",
"id": "1291546"
}],
"title": "\u8c46\u74e3\u7535\u5f71Top250"
}
为了解析上面的json字符串，定义结构如下：
type (
Response struct {
Count int `json:"count"`
Start int `json:"start"`
Total int `json:"total"`
Subject []struct {
Rating struct {
Max int `json:"max"`
Average float32 `json:"average"`
Stars string `json:"stars"`
Min int `json:"min"`
} `json:"rating"`
Genres []string `json:"genres"`
Title string `json:"title"`
Casts []struct {
Alt string `json:"alt"`
Avatars struct {
Small string `json:"small"`
Large string `json:"large"`
Medium string `json:"medium"`
} `json:"avatars"`
} `json:"casts"`
} `json:"subjects"`
Title string `json:"title"`
}
)
可以看出跟应答字符串里的json格式是对应的，Response是整个应答结果的类型名，里面才是具体的字段，定义的时候一定要注意字段类型不能随便填。
完整代码如下：
package main
import (
"encoding/json"
"log"
"net/http"
)
type (
Response struct {
Count int `json:"count"`
Start int `json:"start"`
Total int `json:"total"`
Subject []struct {
Rating struct {
Max int `json:"max"`
Average float32 `json:"average"`
Stars string `json:"stars"`
Min int `json:"min"`
} `json:"rating"`
Genres []string `json:"genres"`
Title string `json:"title"`
Casts []struct {
Alt string `json:"alt"`
Avatars struct {
Small string `json:"small"`
Large string `json:"large"`
Medium string `json:"medium"`
} `json:"avatars"`
} `json:"casts"`
} `json:"subjects"`
Title string `json:"title"`
}
)
func main() {
uri := "http://api.douban.com/v2/movie/top250?start=0&count=2"
resp, err := http.Get(uri)
if err != nil {
log.Println("ERROR", err)
return
}
defer resp.Body.Close()
var res Response
err = json.NewDecoder(resp.Body).Decode(&res)
if err != nil {
log.Println("ERROR", err)
return
}
log.Println(res)
log.Println(res.Subject[0].Rating)
}
log.Println(res.Subject[0].Rating) 仅打印制定的字段，使用类似的方式获取自己想要的字段的值