consumer 抛出Dubbo client can not supported string message原因分析

[fingthinking]

• I have searched the issues of this repository and believe that this is not a duplicate.
• I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

• Dubbo version: 2.
• Operating System version: mac
• Java version: 1.8

Step to reproduce this issue

1. 表现：
   consumer 在某些情况下会抛出Dubbo client can not supported string message异常，并且 message 显示为乱码信息，经查找资料是说消息体 >8M 导致；
2. 实际测试结果：
   我本地测试的时候，均无法复现对应的异常信息，>8M 的表现为 consumer 等待超时，且 provider 抛出Data length too large:异常。

求大神们帮忙分析一下，在什么情况下会出现标题中的那种异常？

[fingthinking]

@beiwei30 hi,能帮忙看看吗

[chickenlj]

Can you please give a full stack trace.

[beiwei30]

@fingthinking this error log comes from https://github.com/apache/incubator-dubbo/blob/master/dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/exchange/support/header/HeaderExchangeHandler.java#L204. Would you mind to attach the relevant info from your dubbo log so that we can analyze further based on that?

[zane-rl]

线上碰到一样的错误：
2018-08-02 17:36:16 [com.alibaba.dubbo.common.logger.slf4j.Slf4jLogger:74] - [DUBBO] Dubbo client can not supported string message: 慩試ZC0(com.tontisa.erpweb.entity.BaseLineTravel�^BID^EerpID^FlineID^FtheDay
theTraffic^GtheFrom^EtheTtheTitle^GtheDestheHotel^FtheCan theFlight^FbySort^FisLock^EadmID^EisDel^Cimg theScenic
updateTime^GaddTime^VbaseLineTravelJourneys<画NN�^B椋炴満NN^L绂忓窞/鍘﹂棬-棣欐腐-閲戣竟 0@璐靛浜庢寚瀹氭椂闂撮泦鍚堜簬鏈哄満鍥介檯鏈哄満鍥介檯鍑哄彂鍘咃紝鎼箻璞崕>瀹㈡満缁忛娓浆鏈洪寰�鏌煍瀵ㄩ閮解�斺�滀笢鏂瑰皬宸撮粠鈥濋噾杈瑰競锛屾櫄椁愬悗涔樿溅鍓嶅線閰掑簵鍏ヤ綇銆�^F褰撳湴4鏄熼厭搴�^A鏅歂悙<'^_N1^G/erp_files/files/336/image/20160219/20150228124025_kcQsy.thumb.700_0_1455850382673.jpeg,/erp_files/files/336/image/20160219/20150226110304_dYmVL.thumb.700_0_1455850382774.jpeg,/erp_files/files/336/image/20160219/20150228111736_LzFMM.thumb.700_0_1455850382791.jpegNJ^@^@^Aat%L^OJ^@^@^Aat%K揘<^\ENN�^E澶у反銆侀鏈篘D1绂忓窞-鏇艰胺 02璐靛浜庢寚瀹氭椂闂村強鍦扮....................................
at com.alibaba.dubbo.remoting.transport.DecodeHandler.received(DecodeHandler.java:52) [dubbo-2.8.4.jar:2.8.4]
at com.alibaba.dubbo.remoting.transport.dispatcher.ChannelEventRunnable.run(ChannelEventRunnable.java:82) [dubbo-2.8.4.jar:2.8.4]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_65]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_65]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_65]

消费端错误返回如上：
1、服务端设置过(查资料有说可能数据太大)：
<dubbo:protocol name="dubbo" port="20893" register="${service.register}" payload="33554432"/>
依然有问题
2、实体类BaseLineTravel：
public class BaseLineTravel implements java.io.Serializable {
private static final long serialVersionUID = 1L;
private Long ID;
private Integer isDel;
private String img;
private String theScenic;

private List<BaseLineTravelJourney> baseLineTravelJourneys;

....
有做序列化处理，BaseLineTravelJourney：
public class BaseLineTravelJourney implements java.io.Serializable 也有处理

@chickenlj @beiwei30

[fingthinking]

@chickenlj @beiwei30 今天又遇到同样的问题了，我怎么也无法分析出来原因，哎~同楼上代码类似，麻烦两位帮忙分析一下。

[lllichen]

@renlei413326889 问下你用的啥序列化协议呢，换个协议还报错吗

[zane-rl]

@lllichen 默认的dubbo协议 <dubbo:protocol name="dubbo" dubbox最新分支

[fingthinking]

@lllichen 我分析不出会有那种协议会走到https://github.com/apache/incubator-dubbo/blob/master/dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/exchange/support/header/HeaderExchangeHandler.java#L204这段代码中去，麻烦一起解惑。

[fingthinking]

@renlei413326889 看看是不是因为这个原因，我在我们公司这么修复的，没毛病。

[zonghaishang]

Are you using telnet in consumer side ?

[zonghaishang]

at com.alibaba.dubbo.remoting.transport.DecodeHandler.received(DecodeHandler.java:52) [dubbo-2.8.4.jar:2.8.4

Have you tried using dubbo (not dubbox) to reproduce it?

[fingthinking]

Are you using telnet in consumer side ?

是的，使用的 dubbox

[zane-rl]

@fingthinking 我按照你的这样处理了，没毛病！现在没有这种乱码问题，最新的dubbo的代码也有处理这种异常情况！

[beiwei30]

@renlei413326889 @fingthinking, dubbo 现在代码里的：

        } catch (Throwable t) {
            // clear buffer
            buffer.writerIndex(savedWriteIndex);
            // send error message to Consumer, otherwise, Consumer will wait till timeout.
            if (!res.isEvent() && res.getStatus() != Response.BAD_RESPONSE) {

buffer.writerIndex(savedWriteIndex); 已经解决了这个问题了吧？

[zonghaishang]

看回复已经解决了，我check了代码 buffer.writerIndex(savedWriteIndex); 和 buffer.clear()是等价的，先关闭这个Issue。