ERROR HeaderExchangeHandler:181 - [DUBBO] Dubbo client can not supported string message: in channe

14:30:26,206 ERROR HeaderExchangeHandler:181 -  [DUBBO] Dubbo client can not supported string message:  in channel: NettyChannel [channel=[id: 0x0139fb49,/10.1.194.163:54613 =>/10.1.194.163:30027]], url: dubbo://10.1.194.163:30027/com.lagou.service.business.plus.api.PlusInvitationListRemoteService?anyhost=true&application=lagou-service-business-c&check=false&codec=dubbo&default.loadbalance=random&dubbo=2.5.3&heartbeat=60000&interface=com.lagou.service.business.plus.api.PlusInvitationListRemoteService&methods=queryAllPositionList,queryValidPositionList&owner=Alan&payload=16777216&pid=12012&protocol=dubbo&retries=1&revision=0.0.1&side=consumer&timeout=5000×tamp=1461133824336&version=0.0.1, dubbo version: 2.5.3, current host: 10.1.194.163
java.lang.Exception: Dubbo client can not supported string message:  in channel: NettyChannel [channel=[id: 0x0139fb49,/10.1.194.163:54613 =>/10.1.194.163:30027]], url: dubbo://10.1.194.163:30027/com.lagou.service.business.plus.api.PlusInvitationListRemoteService?anyhost=true&application=lagou-service-business-c&check=false&codec=dubbo&default.loadbalance=random&dubbo=2.5.3&heartbeat=60000&interface=com.lagou.service.business.plus.api.PlusInvitationListRemoteService&methods=queryAllPositionList,queryValidPositionList&owner=Alan&payload=16777216&pid=12012&protocol=dubbo&retries=1&revision=0.0.1&side=consumer&timeout=5000×tamp=1461133824336&version=0.0.1
at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.received(HeaderExchangeHandler.java:180)
at com.alibaba.dubbo.remoting.transport.DecodeHandler.received(DecodeHandler.java:52)
at com.alibaba.dubbo.remoting.transport.dispatcher.ChannelEventRunnable.run(ChannelEventRunnable.java:82)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)
Dubbo 보고 이상의 오류는 Dubbo가 전송한 데이터 대상이 서열화되지 않아서 괜찮아요.

@SuppressWarnings("serial")
public class InvitationPositionList implements java.io.Serializable

이유
HeaderExchangeHandler.java 소스:

} else if (message instanceof Response) { 
                handleResponse(channel, (Response) message); 
            } else if (message instanceof String) { 
                if (isClientSide(channel)) { 
                    Exception e = new Exception("Dubbo client can not supported string message: " + message + " in channel: " + channel + ", url: " + channel.getUrl()); 
                    logger.error(e.getMessage(), e); 
                } else { 
                    String echo = handler.telnet(channel, (String) message); 
                    if (echo != null && echo.length() > 0) { 
                        channel.send(echo); 
                    } 
                } 
            } else { 
                handler.received(exchangeChannel, message); 
            }