我们使用方法分组来用dubbo，每个分组有自己权限，但是dubbo:registry标签 username & password 不生效，
让我不得不使用
```
    <dubbo:registry
            address="zookeeper://username:pwd@ip:port"
            group="xxx"/>
```
这种写法失效
```
    <dubbo:registry
            address="zookeeper://ip:port"
            username="username"
            password="pwd"/>
```

* Registry centers
     */
    protected List<RegistryConfig> registries;
    protected String registryIds;
    // 
    protected String onconnect;
    /**
     * Dis
     */
    protected String ondisconnect;
    /**
     * The metrics configuration
     */
    protected MetricsConfig metrics;
    protected MetadataReportConfig metadataReportConfig;
    protected ConfigCenterConfig configCenter;
    // 
    private Integer callbacks;
    // 
    private String scope;
    protected String tag;
    /**
     * Check whether the registry config is exists, and then conversion it to {@link RegistryConfig}
     */
    protected void checkRegistry() {
        loadRegistriesFromBackwardConfig();
        convertRegistryIdsToRegistries();
        for (RegistryConfig registryConfig : registries) {
            if (!registryConfig.isValid()) {
                throw new IllegalStateException("No registry config found or it's not a valid config! " +