spring-webflux-i18n RequestParamLocaleContextResolver

public class RequestParamLocaleContextResolver implements LocaleContextResolver{

    @Override
    public LocaleContext resolveLocaleContext(ServerWebExchange exchange) {
        Locale targetLocale = Locale.getDefault();
        List<String> referLang = exchange.getRequest().getQueryParams().get("lang");
        if (referLang != null && !referLang.isEmpty()) {
            String lang = referLang.get(0);
            targetLocale = Locale.forLanguageTag(lang);
        }
        return new SimpleLocaleContext(targetLocale);
    }

    //...

}