如何将两个json值解组到同一变量中？

Question

I frequently come across json that have same structure but different name. How is it possible to assign all of them in same struct. for example

{
    "e":"g"
    "a":[
        {
            "b":"b1",
            "c":"c1"
        }
        ]
}

and

{
    "e":"f"
    "d":[
        {
            "b":"b1",
            "c":"c1"
        }
        ]
}

have same internal structure but could not be unmarsheled into same golang struct.

Answer 1

Using struct tags for decoding json is intended for the most common use cases. For custom behavior implement the Unmarshaler interface (https://play.golang.org/p/rCpCDvWXGP):

type InnerStruct struct {
    B, C string
}
type OuterStruct struct {
    E string
    A []InnerStruct
}

func (o *OuterStruct) UnmarshalJSON(bs []byte) error {
    var intermediate map[string]json.RawMessage
    err := json.Unmarshal(bs, &intermediate)
    if err != nil {
        return err
    }
    // e is just e
    e, ok := intermediate["e"]
    if !ok {
        return fmt.Errorf("invalid json, expected `e`")
    }
    err = json.Unmarshal(e, &o.E)
    if err != nil {
        return err
    }
    // a is a or d
    a, ok := intermediate["a"]
    if !ok {
        a, ok = intermediate["d"]
    }
    if !ok {
        return fmt.Errorf("invalid json, expected `a` or `d`")
    }
    err = json.Unmarshal(a, &o.A)
    if err != nil {
        return err
    }
    return nil
}

In this case I used an intermediate map and delayed the processing of the inner values to match a or d. I'm sure this wasn't the actual data you had to work with, but hopefully it's enough to get you started.