我发现了一些关于如何在go中解码json嵌套对象的帖子,我试图将答案应用到我的问题中,但我只是设法找到了部分解决方案。
我的json文件如下所示:
{
"user":{
"gender":"male",
"age":"21-30",
"id":"80b1ea88-19d7-24e8-52cc-65cf6fb9b380"
},
"trials":{
"0":{"index":0,"word":"WORD 1","Time":3000,"keyboard":true,"train":true,"type":"A"},
"1":{"index":1,"word":"WORD 2","Time":3000,"keyboard":true,"train":true,"type":"A"},
},
"answers":{
"training":[
{"ans":0,"RT":null,"gtAns":"WORD 1","correct":0},
{"ans":0,"RT":null,"gtAns":"WORD 2","correct":0}
],
"test":[
{"ans":0,"RT":null,"gtAns":true,"correct":0},
{"ans":0,"RT":null,"gtAns":true,"correct":0}
]
}
}
基本上我需要解析其中的信息并将它们保存到go结构中。使用下面的代码我设法提取用户信息,但它看起来太复杂了,并且很容易将相同的东西应用到"答案"包含2个数组的字段,每个数组包含100个以上的条目。这是我现在使用的代码:
type userDetails struct {
Id string `json:"id"`
Age string `json:"age"`
Gender string `json:"gender"`
}
type jsonRawData map[string]interface {
}
func getJsonContent(r *http.Request) ( userDetails) {
defer r.Body.Close()
jsonBody, err := ioutil.ReadAll(r.Body)
var userDataCurr userDetails
if err != nil {
log.Printf("Couldn't read request body: %s", err)
} else {
var f jsonRawData
err := json.Unmarshal(jsonBody, &f)
if err != nil {
log.Printf("Error unmashalling: %s", err)
} else {
user := f["user"].(map[string]interface{})
userDataCurr.Id = user["id"].(string)
userDataCurr.Gender = user["gender"].(string)
userDataCurr.Age = user["age"].(string)
}
}
return userDataCurr
}
有什么建议吗?非常感谢!
答案 0 :(得分:3)
您使用interface{}
并且没有利用encoding/json
给您的优势,努力做到这一点。
我做这样的事情(注意我假设" gtAns"字段的类型有错误,我把它作为布尔值,你不能给予足够的知道如何处理" RT"字段的信息:
package main
import (
"encoding/json"
"fmt"
"io"
"log"
"strconv"
"strings"
)
const input = `{
"user":{
"gender":"male",
"age":"21-30",
"id":"80b1ea88-19d7-24e8-52cc-65cf6fb9b380"
},
"trials":{
"0":{"index":0,"word":"WORD 1","Time":3000,"keyboard":true,"train":true,"type":"A"},
"1":{"index":1,"word":"WORD 2","Time":3000,"keyboard":true,"train":true,"type":"A"}
},
"answers":{
"training":[
{"ans":0,"RT":null,"gtAns":true,"correct":0},
{"ans":0,"RT":null,"gtAns":true,"correct":0}
],
"test":[
{"ans":0,"RT":null,"gtAns":true,"correct":0},
{"ans":0,"RT":null,"gtAns":true,"correct":0}
]
}
}`
type Whatever struct {
User struct {
Gender Gender `json:"gender"`
Age Range `json:"age"`
ID IDString `json:"id"`
} `json:"user"`
Trials map[string]struct {
Index int `json:"index"`
Word string `json:"word"`
Time int // should this be a time.Duration?
Train bool `json:"train"`
Type string `json:"type"`
} `json:"trials"`
Answers map[string][]struct {
Answer int `json:"ans"`
RT json.RawMessage // ??? what type is this
GotAnswer bool `json:"gtAns"`
Correct int `json:"correct"`
} `json:"answers"`
}
// Using some custom types to show custom marshalling:
type IDString string // TODO custom unmarshal and format/error checking
type Gender int
const (
Male Gender = iota
Female
)
func (g *Gender) UnmarshalJSON(b []byte) error {
var s string
err := json.Unmarshal(b, &s)
if err != nil {
return err
}
switch strings.ToLower(s) {
case "male":
*g = Male
case "female":
*g = Female
default:
return fmt.Errorf("invalid gender %q", s)
}
return nil
}
func (g Gender) MarshalJSON() ([]byte, error) {
switch g {
case Male:
return []byte(`"male"`), nil
case Female:
return []byte(`"female"`), nil
default:
return nil, fmt.Errorf("invalid gender %v", g)
}
}
type Range struct{ Min, Max int }
func (r *Range) UnmarshalJSON(b []byte) error {
// XXX could be improved
_, err := fmt.Sscanf(string(b), `"%d-%d"`, &r.Min, &r.Max)
return err
}
func (r Range) MarshalJSON() ([]byte, error) {
return []byte(fmt.Sprintf(`"%d-%d"`, r.Min, r.Max)), nil
// Or:
b := make([]byte, 0, 8)
b = append(b, '"')
b = strconv.AppendInt(b, int64(r.Min), 10)
b = append(b, '-')
b = strconv.AppendInt(b, int64(r.Max), 10)
b = append(b, '"')
return b, nil
}
func fromJSON(r io.Reader) (Whatever, error) {
var x Whatever
dec := json.NewDecoder(r)
err := dec.Decode(&x)
return x, err
}
func main() {
// Use http.Get or whatever to get an io.Reader,
// (e.g. response.Body).
// For playground, substitute a fixed string
r := strings.NewReader(input)
// If you actually had a string or []byte:
// var x Whatever
// err := json.Unmarshal([]byte(input), &x)
x, err := fromJSON(r)
if err != nil {
log.Fatal(err)
}
fmt.Println(x)
fmt.Printf("%+v\n", x)
b, err := json.MarshalIndent(x, "", " ")
if err != nil {
log.Fatal(err)
}
fmt.Printf("Re-marshalled: %s\n", b)
}
当然,如果你想重复使用这些子类型,你可以将它们从" Whatever"输入他们自己的命名类型。
另外,请注意使用json.Decoder
而不是提前读取所有数据。通常尽量避免使用ioutil.ReadAll
,除非您确实需要一次性获取所有数据。