code: protected InputStreamReader resolveReader(URL url) {
  
          if (url != null) {
              try {
                  InputStream in = url.openStream();
                  if (in != null)
                      return new InputStreamReader(in, this.encoding);
              } catch (IOException e) {
                  logger.warn("resolve template error", e);
              }
          }
          return null;
      }
docs: <p>resolveReader.</p>
  
  @param url a {@link java.net.URL} object.
  @return a {@link java.io.InputStreamReader} object.