手机解析dns失败什么原因

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.Network;
import android.net.NetworkCapabilities;
import android.net.NetworkRequest;
import android.os.Build;
import android.util.Log;

public class DnsCacheUtil {
    public static void flushDnsCache(Context context) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            if (connectivityManager != null) {
                connectivityManager.requestNetwork(new NetworkRequest.Builder().build(), new ConnectivityManager.NetworkCallback() {
                    @Override
                    public void onAvailable(Network network) {
                        super.onAvailable(network);
                        Log.d("DnsCacheUtil", "Network available, flushing DNS cache");
                        // Perform DNS cache flush operation here
                    }
                });
            }
        } else {
            Log.d("DnsCacheUtil", "Device does not support flushing DNS cache programmatically");
        }
    }
}