Not use reflect create IPInfo object.

[septs]

func makeIPInfo(data string, languageOffset int, fields []string) *IPInfo {
    info := new(IPInfo)
    mapping := map[string]*string{
        "country_name":     &info.CountryName,
        "region_name":      &info.RegionName,
        "city_name":        &info.CityName,
        "owner_domain":     &info.OwnerDomain,
        "isp_domain":       &info.IspDomain,
        "latitude":         &info.Latitude,
        "longitude":        &info.Longitude,
        "timezone":         &info.Timezone,
        "utc_offset":       &info.UtcOffset,
        "china_admin_code": &info.ChinaAdminCode,
        "idd_code":         &info.IddCode,
        "country_code":     &info.CountryCode,
        "continent_code":   &info.ContinentCode,
        "idc":              &info.IDC,
        "base_station":     &info.BaseStation,
        "country_code3":    &info.CountryCode3,
        "european_union":   &info.EuropeanUnion,
        "currency_code":    &info.CurrencyCode,
        "currency_name":    &info.CurrencyName,
        "anycast":          &info.Anycast,
    }
    values := strings.Split(data, "\t")
    values = values[languageOffset : languageOffset+len(fields)]
    for index, value := range values {
        name := fields[index]
        *mapping[name] = value
    }
    return info
}

[ilsanbao]

@septs 暂时不会这么修改，你可以看我们的Java实现