How can I use UTF-8 with org.apache.cxf.jaxrs.client.WebClient create()?

This is about Apache CXF　WebClient, WebClient.create("URL", "username", "password", null);

when I use a UTF-8 username to create a WebClient instance, I ended up with a 401 http error.

I've tried WebClient.encoding("UTF-8"), and WebClient.acceptLanguage("zh_CN"), but neither worked.

Any idea or help is appreciated. Thanks.