手机热点dns无法解析

// 获取当前网络的DNS服务器地址
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkRequest.Builder builder = new NetworkRequest.Builder();
cm.registerNetworkCallback(builder.build(), new ConnectivityManager.NetworkCallback() {
    @Override
    public void onAvailable(Network network) {
        super.onAvailable(network);
        LinkProperties linkProperties = cm.getLinkProperties(network);
        if (linkProperties != null) {
            List<DnsServerAddress> dnsServers = linkProperties.getDnsServers();
            for (DnsServerAddress dnsServer : dnsServers) {
                Log.d("DNS", "DNS Server: " + dnsServer.address);
            }
        }
    }
});