场景：
服务编排框架支持编排webservice服务。call webservice的client是基于cxf做的。为了使用服务编排的开发者调试与定位问题方便，需要将webservice的请求与响应报文打出来。
这个诉求不是很复杂加上LoggingInInterceptor(打印响应报文)与LoggingOutInterceptor(打印请求报文)两个拦截器即可。
好，开始考虑异常场景，当提供webservice的服务后台不通时，理论上也是应该可以打出请求报文的，但是在对cxf的client的httpClientPolicy的chunk设置成false之后，请求的报文就不会被打出了。
分析：
分析源码后发现cxf依赖大量的拦截器，可以说对拦截器这个pattern用的还是比较深入的：
1. 拦截的phase有很多
2.触发拦截后还可以注册回调
3.拦截器形成自己的chain
4.触发拦截器执行过程中还可以动态增加拦截器
触发拦截器调用逻辑的代码在
org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(Message)
的255行： currentInterceptor.handleMessage(message);
通过调用堆栈不难发现，触发输出日志动作是在执行org.apache.cxf.interceptor.MessageSenderInterceptor$MessageSenderEndingInterceptor@17d602ac这个拦截器时。
可以猜测在chunk设置成false是没有成功执行到这个拦截器的。
好，对比两种场景下执行的拦截器的情况
----------------------------------------------
在chunk未关闭的时候：
org.apache.cxf.jaxws.interceptors.HolderOutInterceptor@35185c1c
org.apache.cxf.jaxws.interceptors.SwAOutInterceptor@1b83d46a
org.apache.cxf.jaxws.interceptors.WrapperClassOutInterceptor@696eeb41
org.apache.cxf.binding.soap.interceptor.SoapHeaderOutFilterInterceptor@3b8d3ecd
org.apache.cxf.binding.soap.interceptor.SoapPreProtocolOutInterceptor@50f36fcb
org.apache.cxf.interceptor.MessageSenderInterceptor@48bdd8f7
org.apache.cxf.interceptor.LoggingOutInterceptor@de0353b
org.apache.cxf.interceptor.AttachmentOutInterceptor@28f3964a
org.apache.cxf.interceptor.StaxOutInterceptor@519d5d83
org.apache.cxf.binding.soap.interceptor.SoapOutInterceptor@7d5b68d5
org.apache.cxf.interceptor.WrappedOutInterceptor@60340199
org.apache.cxf.interceptor.BareOutInterceptor@5e1d90a3
org.apache.cxf.binding.soap.interceptor.SoapOutInterceptor$SoapOutEndingInterceptor@54babeeb
org.apache.cxf.interceptor.StaxOutInterceptor$StaxOutEndingInterceptor@27a4431
org.apache.cxf.interceptor.MessageSenderInterceptor$MessageSenderEndingInterceptor@17d602ac
===========================
在chunk设置成false关闭时：
org.apache.cxf.jaxws.interceptors.HolderOutInterceptor@7859857a
org.apache.cxf.jaxws.interceptors.SwAOutInterceptor@1bf5df6a
org.apache.cxf.jaxws.interceptors.WrapperClassOutInterceptor@2db493c7
org.apache.cxf.binding.soap.interceptor.SoapHeaderOutFilterInterceptor@2c661664
org.apache.cxf.binding.soap.interceptor.SoapPreProtocolOutInterceptor@6e1c8760
org.apache.cxf.interceptor.MessageSenderInterceptor@37031ba1
org.apache.cxf.interceptor.LoggingOutInterceptor@a5571f9
org.apache.cxf.interceptor.AttachmentOutInterceptor@2b891cf8
org.apache.cxf.interceptor.StaxOutInterceptor@312437a4
org.apache.cxf.binding.soap.interceptor.SoapOutInterceptor@439e91fe
----------------------------------------------
果然很清晰的发现在org.apache.cxf.binding.soap.interceptor.SoapOutInterceptor执行时出现了异常，使得拦截器执行不下去了，日志如下，显而易见，服务不通：
exception, unwinding now org.apache.cxf.binding.soap.SoapFault: Error writing to XMLStreamWriter. at org.apache.cxf.binding.soap.interceptor.SoapOutInterceptor.writeSoapEnvelopeStart(SoapOutInterceptor.java:175) at org.apache.cxf.binding.soap.interceptor.SoapOutInterceptor.handleMessage(SoapOutInterceptor.java:81) at org.apache.cxf.binding.soap.interceptor.SoapOutInterceptor.handleMessage(SoapOutInterceptor.java:61) at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:255) at org.apache.cxf.endpoint.ClientImpl.invoke(ClientImpl.java:544) at org.apache.cxf.endpoint.ClientImpl.invoke(ClientImpl.java:341) at org.apache.cxf.endpoint.ClientImpl.invoke(ClientImpl.java:294) at org.apache.cxf.frontend.ClientProxy.invokeSync(ClientProxy.java:73) at org.apache.cxf.jaxws.JaxWsClientProxy.invoke(JaxWsClientProxy.java:124) at com.sun.proxy.$Proxy26.queryUser(Unknown Source) at org.simonme.demo.cxf.client.user.UserService_UserServicePort_Client.main(UserService_UserServicePort_Client.java:77) Caused by: javax.xml.stream.XMLStreamException: java.net.ConnectException: Connection refused: connect at com.sun.xml.internal.stream.writers.XMLStreamWriterImpl.writeStartElement(XMLStreamWriterImpl.java:1344) at org.apache.cxf.binding.soap.interceptor.SoapOutInterceptor.writeSoapEnvelopeStart(SoapOutInterceptor.java:122) ... 10 more Caused by: java.net.ConnectException: Connection refused: connect at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) at java.net.Socket.connect(Socket.java:579)
org.apache.cxf.io.AbstractThresholdOutputStream.write(int)
@Override public void write(int b) throws IOException { if (buffer != null) { buffer.write(b); if (buffer.size() >= threshold) { thresholdReached(); unBuffer(); } return; } super.write(b); }
threshold 在chunk设置成false时 为0 ，不设置时(默认true) 为4096
当设置成0时，一定会触发unBuffer逻辑，这个逻辑会去请求后台，此时后台又不通 那么就出现了异常。具体可以看上面日志的异常栈。
如何设置的4096
看org.apache.cxf.transports.http.configuration.HTTPClientPolicy.getChunkingThreshold()
threshold 如何设置的0
if (csPolicy.isAllowChunking() && isChunkingSupported(message, connection.getRequestMethod())) { //TODO: The chunking mode be configured or at least some // documented client constant. //use -1 and allow the URL connection to pick a default value isChunking = true; chunkThreshold = csPolicy.getChunkingThreshold(); if (chunkThreshold <= 0) { chunkThreshold = 0; connection.setChunkedStreamingMode(-1); } }
org.apache.cxf.transport.http.HTTPConduit.prepare(Message)
方法中chunkThreshold初始值为0 因为isAllowChunking为false 所以上面逻辑不会进入，所以chunkThreshold依然为0
为什么设置启用chunk，就要设置成4096？
you’ll be receiving in some arbitrary chunk size, (4096 or 8192 is frequently a good match for network buffer sizes)
还有些类库 默认是2048的
The default chunk size in Apache HttpClient 4.3 is set to 2048 bytes.
如何解决这个问题，可以考虑修改(重写)这个拦截器的触发时机等。
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demo代码在 https://github.com/xiaguangme/demo/tree/master/01.cxf_2.3.11