AsyncTask不显示HTML的内容

protected String doInBackground(Void... params) {
    String htmlContent = null;
    try {
        URL url = new URL("http://example.com");  // 替换为要获取HTML内容的URL地址
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");

        InputStream in = new BufferedInputStream(connection.getInputStream());
        htmlContent = readStream(in);

        connection.disconnect();
    } catch (IOException e) {
        e.printStackTrace();
    }

    return htmlContent;
}

private String readStream(InputStream inputStream) throws IOException {
    BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
    StringBuilder result = new StringBuilder();
    String line;
    while ((line = reader.readLine()) != null) {
        result.append(line);
    }
    reader.close();

    return result.toString();
}

protected void onPostExecute(String htmlContent) {
    // 在这里更新UI，将HTML内容显示在WebView中
    WebView webView = findViewById(R.id.webview);
    webView.loadData(htmlContent, "text/html", "UTF-8");
}