How to decode json into structs
You must Uppercase struct fields:
type MxRecords struct {
Value string `json:"value"`
Ttl int `json:"ttl"`
Priority int `json:"priority"`
HostName string `json:"hostName"`
}
type Data struct {
MxRecords []MxRecords `json:"mxRecords"`
}
http://play.golang.org/p/EEyiISdoaE
The encoding/json
package can only decode into exported struct fields. Your Data.mxRecords
member is not exported, so it is ignored when decoding. If you rename it to use a capital letter, the JSON package will notice it.
You will need to do the same thing for all the members of your MxRecords
type.
As per the go documentaiton about json.Unmarshal, you can only decode toward exported fields, the main reason being that external packages (such as encoding/json
) cannot acces unexported fields.
If your json doesn't follow the go convention for names, you can use the json
tag in your fields to change the matching between json key and struct field.
Exemple:
package main
import (
"fmt"
"encoding/json"
)
type T struct {
Foo string `json:"foo"`
priv string `json:"priv"`
}
func main() {
text := []byte(`{"foo":"bar", "priv":"nothing"}`)
var t T
err := json.Unmarshal(text, &t)
if err != nil {
panic(err)
}
fmt.Println(t.Foo) // prints "bar"
fmt.Println(t.priv) // prints "", priv is not exported
}