英文:
How to unmarshal two json values into same variable?
问题
我经常遇到具有相同结构但不同名称的 JSON 数据。如何将它们都分配给同一个结构体？例如：
{
"e":"g",
"a":[
{
"b":"b1",
"c":"c1"
}
]
}
和
{
"e":"f",
"d":[
{
"b":"b1",
"c":"c1"
}
]
}
这两个 JSON 数据具有相同的内部结构，但无法解析为相同的 Golang 结构体。
英文:
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.
答案1
得分: 1
使用结构标签来解码JSON是为了最常见的用例。对于自定义行为，请实现Unmarshaler接口（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
}
在这个例子中，我使用了一个中间映射，并延迟处理内部值以匹配a或d。我确定这不是你要处理的实际数据，但希望这足以让你开始。
英文:
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.
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