通过request获得请求 域名

StringBuffer requestURL = request.getRequestURL();
        URI ip = IpUtil.getIP(new URI(requestURL.toString()));

public class IpUtil {

    public static URI getIP(URI uri) {
        URI effectiveURI = null;

        try {
            // URI(String scheme, String userInfo, String host, int port, String
            // path, String query,String fragment)
            effectiveURI = new URI(uri.getScheme(), uri.getUserInfo(), uri.getHost(), uri.getPort(), null, null, null);
        } catch (Throwable var4) {
            effectiveURI = null;
        }

        return effectiveURI;
    }
}