CXF client在并发下的线程安全问题

核心提示： * Session support - if you turn on sessions support (see jaxws spec), the session cookie is stored in the conduit. Thus, it would fall into the abov

* Session support - if you turn on sessions support (see jaxws spec), the session cookie is stored in the conduit. Thus, it would fall into the above rules on conduit settings and thus be shared across threads.

For the conduit issues, you COULD install a new ConduitSelector that uses a thread local or similar. That's a bit complex though.

For most "simple" use cases, you can use CXF proxies on multiple threads. The above outlines the workarounds for the others.

2) cxf的wiki中谈到Client API中的Proxy-based API

wiki 地址: http://cwiki.apache.org/CXF20DOC/jax-rs.html

Limitations

Proxy methods can not have @Context method parameters and subresource methods returning Objects can not be invoked - perhaps it is actually not too bad at all - please inject contexts as field or bean properties and have subresource methods returning typed classes : interfaces, abstract classes or concrete implementations.

Proxies are currently not thread-safe.

3) thread safe issue caused by XMLOutputFactoryImpl

找到的一个cxf的bug，https://issues.apache.org/jira/browse/CXF-2229

Description　　　

Currently CXF calls StaxUtils.getXMLOutputFactory() to get the cached instance of XMLOutputFactoryImpl. But XMLOutputFactoryImpl.createXMLStreamWriter is not thread-safe. See below.

javax.xml.stream.XMLStreamWriter　createXMLStreamWriter(javax.xml.transform.stream.StreamResult　sr,　String　encoding)　throws　javax.xml.stream.XMLStreamException　{
　　　　　　　　　try{
　　　　　　　　　　　if(fReuseInstance　&&　fStreamWriter　!=　null　&&　fStreamWriter.canReuse()　&&　!fPropertyChanged){
　　　　　　　　　　　　　　　fStreamWriter.reset();
　　　　　　　　　　　　　　　fStreamWriter.setOutput(sr,　encoding);
　　　　　　　　　　　　　　　if(DEBUG)System.out.println("reusing　instance,　object　id　:　"　+　fStreamWriter);
　　　　　　　　　　　　　　　return　fStreamWriter;
　　　　　　　　　　　}
　　　　　　　　　　　return　fStreamWriter　=　new　XMLStreamWriterImpl(sr,　encoding,　new　PropertyManager(fPropertyManager));　--　this　is　not　thread　safe,　since　the　new　instance　is　assigned　to　the　field　fStreamWriter　first,　then　it　is　possible　that　different　threads　get　the　same　XMLStreamWriterImpl　when　they　call　this　method　at　the　same　time.
　　　　　　　　　}catch(java.io.IOException　io){
　　　　　　　　　　　throw　new　XMLStreamException(io);
　　　　　　　}
　　　}

The solution might be, StaxUtils.getXMLOutputFactory() method creates a new instance of XMLOutputFactory every time, don't cache it.