CXF client在并发下的线程安全问题

修改后的客户端代码在之后的测试中，非常稳定,没有再出现上面的异常，问题算是解决了。

我对cxf不是很熟悉，找了一下也没有找到到底是那里造成的线程不安全，google了一下找到几个地方，但是似乎还不能完全说明问题。先列出来慢慢研究：

1) Are JAX-WS client proxies thread safe?

装载自这里：http://cxf.apache.org/faq.html#FAQ-AreJAXWSclientproxiesthreadsafe%253F

Official JAX-WS answer: No. According to the JAX-WS spec, the client proxies are NOT thread safe. To write portable code, you should treat them as non-thread safe and synchronize access or use a pool of instances or similar.

CXF answer: CXF proxies are thread safe for MANY use cases. The exceptions are:

* Use of ((BindingProvider)proxy).getRequestContext() - per JAX-WS spec, the request context is PER INSTANCE. Thus, anything set there will affect requests on other threads. With CXF, you can do:

((BindingProvider)proxy).getRequestContext().put("thread.local.request.context", "true");

((BindingProvider)proxy).getRequestContext().put("thread.local.request.context", "true");

and future calls to getRequestContext() will use a thread local request context. That allows the request context to be threadsafe. (Note: the response context is always thread local in CXF)

* Settings on the conduit - if you use code or configuration to directly manipulate the conduit (like to set TLS settings or similar), those are not thread safe. The conduit is per-instance and thus those settings would be shared.