default String getUrlContent(String urlStr, @Nullable String authHeader) {
    StringBuilder sb = new StringBuilder();
    try {
      URL url = new URL(urlStr);
      HttpURLConnection httpConnection = (HttpURLConnection) url.openConnection();
      if (authHeader != null) {
        httpConnection.setRequestProperty("Authorization", authHeader);
      }
      if (httpConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
        InputStream in = httpConnection.getInputStream();
        InputStreamReader isr = new InputStreamReader(in);
        BufferedReader bufr = new BufferedReader(isr);
        String str;
        while ((str = bufr.readLine()) != null) {
          sb.append(str);
          sb.append('\n');
        }
        bufr.close();
      } else {
        return null;
      }
    } catch (Exception e) {
      e.printStackTrace();
      return null;
    }
    return sb.toString();
  }
Return the {@link ClusterConfig} for developers to set values before test.
integration-test/src/main/java/org/apache/iotdb/itbase/env/BaseEnv.java