使用背景：今天在spring-cloud项目中，使用多线程异步调用微服务出现的错误
No thread-bound request found: Are you referring to request attributes outside of an actual web request, or processing a request outside of the originally receiving thread? If you are actually operating within a web request and still receive this message, your code is probably running outside of DispatcherServlet/DispatcherPortlet: In this case, use RequestContextListener or RequestContextFilter to expose the current request。
具体场景：
我的微服务调用有自己的统一拦截器RequestIntercepter来输出调用信息，在其中使用RequestContextHolder来获取request信息，发现异步调用时，主线程结束后，子线程就获取不到request，会报以上错误信息。
解决思路：
1.将主线程的request和session信息放进ThreadLocal里，透传到子线程再去获取，这种我还没试（稍后有时间弄）。
2.在开启新线程之前，将servletRequestAttributes设置为子线程共享
ServletRequestAttributes servletRequestAttributes = (ServletRequestAttributes)RequestContextHolder.getRequestAttributes();
RequestContextHolder.setRequestAttributes(servletRequestAttributes,true);//设置子线程共享
