问题
I am attempting to read in a JSON file in Golang, modifying this JSON file, and then creating a new JSON file/writing over this JSON file. I have seen several samples online, but can't seem to put two and two together to get the required result. I tried just making my own JSON str in GO and modifying that, but have still failed.
package main
import (
"encoding/json"
"fmt"
)
type Person struct {
Name string
Age int
Details interface{}
}
func main() {
//I created a simple Json structure here to play with
str := `{"name": "A",
"age":20,
"details": {"salary":100000000}
}`
var data Person
err := json.Unmarshal([]byte(str), &data)
if err != nil {
panic(err)
}
//I make a map so that I can adjust the value of the salary
details, ok := data.Details.(map[string]interface{})
if ok {
details["salary"] = 999999
}
//Change the other values of a Person
data.Name = "B"
data.Age = 19
fmt.Println(data)
//SAMPLE OUTPUT: {B 19 map[salary:999999]}
}
I have made several attempts with reading the file, below is my best attempt:
package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
)
/* Create the structure that follows the outline of the JSON file*/
type UserType struct {
User []struct {
CdbID string `json:"cdb_id"`
Firstname string `json:"firstname"`
Lastname string `json:"lastname"`
Phone int64 `json:"phone"`
Email string `json:"email"`
Address []struct {
Street string `json:"street"`
City string `json:"city"`
Zip string `json:"zip"`
Country string `json:"country"`
} `json:"address"`
Authenticators []struct {
Name string `json:"name"`
Phone int64 `json:"phone"`
} `json:"authenticators"`
VoiceSig string `json:"voice_sig"`
VoicesigCreatedTime string `json:"voicesig_created_time"`
Status string `json:"status"`
} `json:"user"`
}
func main() {
file, err := ioutil.ReadFile("user.json") //Read File
if err != nil {
fmt.Print("Error:", err)
}
var u UserType
json.Unmarshal(file, &u) //Parse the Json-encoded Data and store the results in u
result, e := json.Marshal(u) //Returns the Json encoding of u into the variable result
if e != nil {
fmt.Println("error", err)
}
os.Stdout.Write(result) //The line of code golang.org uses to print the Json encoding
}
This is a sample output:
{
"user": [{
"cdb_id":"",
"firstname":"Tom",
"lastname":"Bradley",
"phone":14155555555,
"email":"tom@gmail.com",
"address":[{
"street":"4343 shoemaker ave",
"city":"Brea",
"zip":"92821",
"country":"USA"
}],
"authenticators":[{
"name":"Lisa Hayden",
"phone":15625555555
},{
"name":"Pavan M",
"phone":17145555555
}],
"voice_sig":"242y5-4546-555kk54-437879ek545",
"voicesig_created_time":"2017-08-02T21:27:44+0000",
"status":"verified"
}]
}
I am just confused on how to modify what I want, specifically the "Authenticators" of the aforementioned sample output. Thanks!
回答1:
Add a declaration
type Authenticator struct {
Name string `json:"name"`
Phone int64 `json:"phone"`
}
and change
Authenticators []struct {
Name string `json:"name"`
Phone int64 `json:"phone"`
} `json:"authenticators"`
to
Authenticators []Authenticator `json:"authenticators"`
Then, to add an authenticator to the first user:
u.User[0].Authenticators = append(u.User[0].Authenticators, Authenticator{
Name: "John Doe",
Phone: 1234567890,
})
来源:https://stackoverflow.com/questions/43713952/modifying-json-file-using-golang