code: private File findPathResource(@NonNull String httpPath) {
          if ("/".equals(httpPath)) {
              File indexFile = new File(mRootPath, getIndexFileName());
              if (indexFile.exists() && indexFile.isFile()) {
                  return indexFile;
              }
          } else {
              File sourceFile = new File(mRootPath, httpPath);
              if (sourceFile.exists()) {
                  if (sourceFile.isFile()) {
                      return sourceFile;
                  } else {
                      File childIndexFile = new File(sourceFile, getIndexFileName());
                      if (childIndexFile.exists() && childIndexFile.isFile()) {
                          return childIndexFile;
                      }
                  }
              }
          }
          return null;
      }
docs: Find the path specified resource.
  
  @param httpPath path.
  
  @return return if the file is found.