- [ ] I have searched the [issues](https://github.com/apache/incubator-dubbo/issues) of this repository and believe that this is not a duplicate.
- [ ] I have checked the [FAQ](https://github.com/apache/incubator-dubbo/blob/master/FAQ.md) of this repository and believe that this is not a duplicate.

### Environment

* Dubbo version: xxx
* Operating System version: xxx
* Java version: xxx

### Steps to reproduce this issue

1. xxx
2. xxx
3. xxx

Pls. provide [GitHub address] to reproduce this issue.

### Expected Result

What do you expected from the above steps？

### Actual Result

What actually happens?

If there is an exception, please attach the exception trace:

```
Just put your stack trace here!
```

for (Invoker<T> invoker : new ArrayList<Invoker<T>>(localUrlInvokerMap.values())) {
                if (invoker.isAvailable()) {
                    return true;
                }
            }
        }
        return false;
    }
    public void buildRouterChain(URL url) {
        this.setRouterChain(RouterChain.buildChain(url));
    }
    /**
     * Haomin: added for test purpose
     */
    public Map<String, Invoker<T>> getUrlInvokerMap() {
        return urlInvokerMap;
    }
    public List<Invoker<T>> getInvokers() {
        return invokers;
    }
    private boolean isValidCategory(URL url) {
        String category = url.getParameter(CATEGORY_KEY, DEFAULT_CATEGORY);
        if ((ROUTERS_CATEGORY.equals(category) || ROUTE_PROTOCOL.equals(url.getProtocol())) ||
                PROVIDERS_CATEGORY.equals(category) ||
                CONFIGURATORS_CATEGORY.equals(category) || DYNAMIC_CONFIGURATORS_CATEGORY.equals(category) ||
                APP_DYNAMIC_CONFIGURATORS_CATEGORY.equals(category)) {
            return true;
        }
        logger.warn("Unsupported category " + category + " in notified url: " + url + " from registry " +
                getUrl().getAddress() + " to consumer " + NetUtils.getLocalHost());