![image](https://user-images.githubusercontent.com/26990889/143370839-615581cb-28f9-4ba3-a110-ab58a2c97b77.png)
apollo 配置中心的 close 方法被注释，导致调用的时候直接调用接口的 default 方法，接口的默认实现是抛异常
ConfigFile configFile = ConfigService.getConfigFile(group, ConfigFileFormat.Properties);
        if (configFile == null) {
            throw new IllegalStateException("There is no namespace named " + group + " in Apollo.");
        }
        return configFile.getContent();
    }
    /**
     * This method will be used by Configuration to get valid value at runtime.
     * The group is expected to be 'app level', which can be fetched from the 'config.appnamespace' in url if necessary.
     * But I think Apollo's inheritance feature of namespace can solve the problem .
     */
    @Override
    public String getInternalProperty(String key) {
        return dubboConfig.getProperty(key, null);
    }
    /**
     * Ignores the group parameter.
     *
     * @param key   property key the native listener will listen on
     * @param group to distinguish different set of properties
     * @return
     */
    private ApolloListener createTargetListener(String key, String group) {
        return new ApolloListener();
    }
    public class ApolloListener implements ConfigChangeListener {
        private Set<ConfigurationListener> listeners = new CopyOnWriteArraySet<>();
        ApolloListener() {
        }
        @Override