系统中有自己的Netty服务器，同时指定Dubbo用Netty，然后LoggingHandler就没法用了。下面的代码回导致我的Netty服务器无法使用Netty自带的日志体系。如果我强制自己的Netty服务器晚于Dubbo加载，那么Dubbo也是无法使用到DubboLogger的。
```
public class NettyHelper {

    public static void setNettyLoggerFactory() {
        InternalLoggerFactory factory = InternalLoggerFactory.getDefaultFactory();
        if (factory == null || !(factory instanceof DubboLoggerFactory)) {
            InternalLoggerFactory.setDefaultFactory(new DubboLoggerFactory());
        }
    }
```
# Added content in English. Help with Google Translate
System is TCP server using Netty4, and Dubbo is specified to use Netty4. When I add LoggingHandler to ChannelPipeline of my System, The log is not expected. 
Like this:
![image](https://user-images.githubusercontent.com/11850956/37442060-5a02eabc-283f-11e8-939a-68255f8912b2.png)

I tracked the code and found the Logger is `com.alibaba.dubbo.remoting.transport.netty4.logging.NettyHelper.DubboLogger` instead of `io.netty.util.internal.logging.Slf4JLogger`.  DubboLogger added other content arount the original log. The NeetyHelper replace the InternalLoggerFactory when Dubbo loading, like the code block above shows.
# By the way.
My system build by Spring Boot, use default logging framework which is Slf4j + Logback.
Dubbo's logger is not extend default logger, but replace it.
![image](https://user-images.githubusercontent.com/11850956/37442386-0585c494-2841-11e8-8f8f-354e7f226726.png)

try {
            if (channels != null) {
                channels.clear();
            }
        } catch (Throwable e) {
            logger.warn(e.getMessage(), e);
        }
    }
    @Override
    public Collection<Channel> getChannels() {
        Collection<Channel> chs = new HashSet<Channel>();
        for (Channel channel : this.channels.values()) {
            if (channel.isConnected()) {
                chs.add(channel);
            } else {
                channels.remove(NetUtils.toAddressString(channel.getRemoteAddress()));
            }
        }
        return chs;
    }
    @Override
    public Channel getChannel(InetSocketAddress remoteAddress) {
        return channels.get(NetUtils.toAddressString(remoteAddress));
    }
    @Override
    public boolean isBound() {
        return channel.isActive();
    }
}