DUBBO-125 改进日志输出

git-svn-id: http://code.alibabatech.com/svn/dubbo/trunk@613 1a56cb94-b969-4eaa-88fa-be21384802f2

dubbo-remoting/src/main/java/com/alibaba/dubbo/remoting/transport/AbstractClient.java

@@ -259,9 +259,10 @@ public abstract class AbstractClient extends AbstractEndpoint implements Client
         if (send_reconnect && !isConnected()){
             connect();
         }
-        Channel channel = getChannel();
+        Channel channel = getChannel();
+        //TODO getChannel返回的状态是否包含null需要改进
         if (channel == null || ! channel.isConnected()) {
-          throw new RemotingException(this, channel == null ? "channel is null " : (" channel is closed ") +". url:" + getUrl());
+          throw new RemotingException(this, "message can not send, because channel is closed . url:" + getUrl());
         }
         channel.send(message, sent);
     }