[英]Unmarshal Json data in a specific struct
I want to unmarshal the following JSON data in Go: 我想在Go中解组以下JSON数据:
b := []byte(`{"Asks": [[21, 1], [22, 1]] ,"Bids": [[20, 1], [19, 1]]}`)
I know how to do that, i define a struct like this: 我知道如何做到这一点,我定义了这样的结构:
type Message struct {
Asks [][]float64 `json:"Bids"`
Bids [][]float64 `json:"Asks"`
}
What i don't know is if there is a simple way to specialize this a bit more. 我不知道的是,是否有一种简单的方法可以将这一点专门化。 I would like to have the data after the unmarshaling in a format like this:
我希望在解组之后以这样的格式获取数据:
type Message struct {
Asks []Order `json:"Bids"`
Bids []Order `json:"Asks"`
}
type Order struct {
Price float64
Volume float64
}
So that i can use it later after unmarshaling like this: 所以我可以在解组之后再使用它:
m := new(Message)
err := json.Unmarshal(b, &m)
fmt.Println(m.Asks[0].Price)
I don't really know how to easy or idiomatically do that in GO so I hope that there is a nice solution for that. 我真的不知道在GO中如何轻松或惯用,所以我希望有一个很好的解决方案。
You can do this with by implementing the json.Unmarshaler
interface on your Order
struct. 您可以通过在
Order
结构上实现json.Unmarshaler
接口来完成此操作 。 Something like this should do: 这样的事情应该做:
func (o *Order) UnmarshalJSON(data []byte) error {
var v [2]float64
if err := json.Unmarshal(data, &v); err != nil {
return err
}
o.Price = v[0]
o.Volume = v[1]
return nil
}
This basically says that the Order
type should be decoded from a 2 element array of floats rather than the default representation for a struct (an object). 这基本上表示
Order
类型应该从2元素浮点数组中解码,而不是结构(对象)的默认表示。
You can play around with this example here: http://play.golang.org/p/B35Of8H1e6 你可以在这里玩这个例子: http : //play.golang.org/p/B35Of8H1e6
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