go - Unmarshal json to reflected struct -


is possible unmarshal json struct made reflection without hardcoding original type?

package main  import (   "fmt"   "encoding/json"   "reflect" )  type employee struct {   firstname string     `json:"firstname"` }  func main() {   //original struct   orig := new(employee)    t := reflect.typeof(orig)   v := reflect.new(t.elem())    //reflected struct   new := v.elem().interface().(employee)    // unmarshal reflected struct   json.unmarshal([]byte("{\"firstname\": \"bender\"}"), &new)    fmt.printf("%+v\n", new) }

i used cast employee in example. if don't know type?

when use v unmarhaling struct zeroed. 

json.unmarshal([]byte("{\"firstname\": \"bender\"}"), v)

when omit cast map. understandable

json.unmarshal([]byte("{\"firstname\": \"bender\"}"), v.elem().interface())

the problem here if omit type assertion here:

new := v.elem().interface()

the new inferred have interface{} type.

then when take address unmarshal, type of &new *interface{} (pointer interface{}) , unmarshal not work expect.

you can avoid type assertion if instead of getting elem() work directly pointer reference.

func main() {   //original struct   orig := new(employee)    t := reflect.typeof(orig)   v := reflect.new(t.elem())    // reflected pointer   newp := v.interface()    // unmarshal reflected struct pointer   json.unmarshal([]byte("{\"firstname\": \"bender\"}"), newp)    fmt.printf("%+v\n", newp) }

playground: https://play.golang.org/p/ltbu-1pqm4


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