dubbo consumer

对消费者来说，配置dubbo.protocol.host没用，消费者对应的URL中的ip字段通过如下方法获得

NetUtils.getLocalHost(),

 有时候这个方法返回的ip并不是我们期待的IP，甚至是一个外网的IP，看起来十分诡异的样子

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RegistryProtocol

    private <T> Invoker<T> doRefer(Cluster cluster, Registry registry, Class<T> type, URL url) {
        RegistryDirectory<T> directory = new RegistryDirectory<T>(type, url);
        directory.setRegistry(registry);
        directory.setProtocol(protocol);
        URL subscribeUrl = new URL(Constants.CONSUMER_PROTOCOL, NetUtils.getLocalHost(), 0, type.getName(), directory.getUrl().getParameters());
        if (! Constants.ANY_VALUE.equals(url.getServiceInterface())
                && url.getParameter(Constants.REGISTER_KEY, true)) {
            registry.register(subscribeUrl.addParameters(Constants.CATEGORY_KEY, Constants.CONSUMERS_CATEGORY,
                    Constants.CHECK_KEY, String.valueOf(false)));
        }
        directory.subscribe(subscribeUrl.addParameter(Constants.CATEGORY_KEY, 
                Constants.PROVIDERS_CATEGORY 
                + "," + Constants.CONFIGURATORS_CATEGORY 
                + "," + Constants.ROUTERS_CATEGORY));
        return cluster.join(directory);
    }