我從服務器收到一條消息，如[0，“on”，[6，1，5，“market”，45.7]]，并將其保存到[]interface{}變量。我想用這個數組的值初始化結構。我對Go來說是全新的，并嘗試這樣做：import "golang.org/x/net/websocket"...var msg []interface{}// Server send response: `[0,"on",[6,1,5,"market",45.7]]`if err := websocket.Message.Receive(ws, &msg); err != nil { logger.Println(err)} else { type Order struct { ID int32, GID int32, CID int32, Type string, Amount float64 } // here msg is [0,"on",[6,1,5,"market",45.7]] switch msg[1] { case "on": if rawOrder, ok := msg[2].([]interface{}); ok { order := Order{int32(rawOrder[0]), int32(rawOrder[1]), int32(rawOrder[2]), string(rawOrder[3]), float64(rawOrder[4])} }}但是我收到一個錯誤“無法將'interface{}'類型的表達式轉換為'int32'”類型，下一步是為每個rawOrder[i]類型使用switch，但它太長了。我怎樣才能輕松做到？
1 回答
RISEBY
TA貢獻1856條經驗 獲得超5個贊
如果您知道websocket上使用的編解碼器將始終是json，則可以正式定義并為其提供一個函數來為您進行解碼。OrderUnmarshalJSON
import "golang.org/x/net/websocket"
type Order struct {
ID, GID, CID int32
Type string
Amount float64
}
func (o *Order) UnmarshalJSON(data []byte) error {
var first []json.RawMessage
err := json.Unmarshal(data, &first)
if err != nil {
return fmt.Errorf("invalid order, must be array: %w", err)
}
if len(first) != 3 {
return fmt.Errorf("invalid order, length must be 3, got %d", len(first))
}
var second string
err = json.Unmarshal(first[1], &second)
if err != nil {
return fmt.Errorf("invalid order, second element must be string: %w", err)
}
switch second {
case "on":
var third []json.RawMessage
err = json.Unmarshal(first[2], &third)
if err != nil {
return fmt.Errorf("invalid order, third element must be array: %w", err)
}
if len(third) != 5 {
return fmt.Errorf("invalid order, element 3 length must be 5, got %d", len(third))
}
for i, f := range []interface{}{&o.ID, &o.GID, &o.CID, &o.Type, &o.Amount} {
err = json.Unmarshal(third[i], f)
if err != nil {
return fmt.Errorf("invalid order, wrong type for element 3[%d]: %w", i, err)
}
}
return nil
}
return fmt.Errorf("invalid order, unknown type %q", second)
}
...
var msg *Order
// Server send response: `[0,"on",[6,1,5,"market",45.7]]`
if err := websocket.JSON.Receive(ws, &msg); err != nil {
logger.Println(err)
}
// msg is now an &Order{ID:6, GID:1, CID:5, Type:"market", Amount:45.7}
}
該功能之所以巨大，是因為您的API很糟糕。如果您控制服務器;那么你應該避免在同一數組中使用混合類型，你應該避免對關系數據使用數組。UnmarshalJSON
- 1 回答
- 0 關注
- 109 瀏覽
添加回答
舉報
0/150
提交
取消