apollo-client/src/main/java/com/ctrip/framework/apollo/spi/DefaultConfigFactory.java/DefaultConfigFactory/trimNamespaceFormat
class DefaultConfigFactory:  String trimNamespaceFormat(String namespaceName, ConfigFileFormat format) {
    String extension = "." + format.getValue();
    if (!namespaceName.toLowerCase().endsWith(extension)) {
      return namespaceName;
    }

    return namespaceName.substring(0, namespaceName.length() - extension.length());
  }