OnceDo 方法写错了<br />
func OnceDo(client *redis.Client, key string, obj interface{}, expiration time.Duration, do func() (data interface{}, err error)) (err error) {
if RExists(client, key) == true {
value, err := client.Get(context.Background(), key).Bytes()
if err == nil {
return json.Unmarshal(value, obj)
}
}

newData, oErr := do()
if oErr == nil {
p, mErr := json.Marshal(newData)
if mErr == nil {
json.Unmarshal(p, obj)
return client.Set(context.Background(), key, p, expiration).Err()
}
return mErr
}
return err
}