You need to export the User.name
field so that the json
package can see it. Rename the name
field to Name
.
package main
import (
"fmt"
"encoding/json"
)
type User struct {
Name string
}
func main() {
user := &User{Name: "Frank"}
b, err := json.Marshal(user)
if err != nil {
fmt.Println(err)
return
}
fmt.Println(string(b))
}
Output:
{"Name":"Frank"}
Related issue:
I was having trouble converting struct to JSON, sending it as response from Golang, then, later catch the same in JavaScript via Ajax.
Wasted a lot of time, so posting solution here.
In Go:
// web server
type Foo struct {
Number int `json:"number"`
Title string `json:"title"`
}
foo_marshalled, err := json.Marshal(Foo{Number: 1, Title: "test"})
fmt.Fprint(w, string(foo_marshalled)) // write response to ResponseWriter (w)
In JavaScript:
// web call & receive in "data", thru Ajax/ other
var Foo = JSON.parse(data);
console.log("number: " + Foo.number);
console.log("title: " + Foo.title);
Struct values encode as JSON objects. Each exported struct field becomes a member of the object unless:
The empty values are false, 0, any nil pointer or interface value, and any array, slice, map, or string of length zero. The object's default key string is the struct field name but can be specified in the struct field's tag value. The "json" key in the struct field's tag value is the key name, followed by an optional comma and options.
You can define your own custom MarshalJSON and UnmarshalJSON methods and intentionally control what should be included, ex:
package main
import (
"fmt"
"encoding/json"
)
type User struct {
name string
}
func (u *User) MarshalJSON() ([]byte, error) {
return json.Marshal(&struct {
Name string `json:"name"`
}{
Name: "customized" + u.name,
})
}
func main() {
user := &User{name: "Frank"}
b, err := json.Marshal(user)
if err != nil {
fmt.Println(err)
return
}
fmt.Println(string(b))
}
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With