标签：RoCE version 打印 oid div buffer ram ide out
zuul的核心逻辑都是由一系列filter过滤器链实现的，但是filter的类型不同，执行的时机也不同，效果自然也不一样，主要特点如下：
zuul内部有一套完整的机制，可以动态读取编译运行filter机制，filter与filter之间不直接通信，在请求线程中会通过RequestContext来共享状态，它内部是用ThreadLocal实现的，例如HttpServletRequest、HttpServletResponse、异常信息等。部分源码如下：
public class RequestContext extends ConcurrentHashMap<String, Object> { private static final Logger LOG = LoggerFactory.getLogger(RequestContext.class); protected static Class<? extends RequestContext> contextClass = RequestContext.class; private static RequestContext testContext = null; protected static final ThreadLocal<? extends RequestContext> threadLocal = new ThreadLocal<RequestContext>() { @Override protected RequestContext initialValue() { try { return contextClass.newInstance(); } catch (Throwable e) { throw new RuntimeException(e); } } };
//.......
}
zuul中不同类型的filter执行逻辑的核心在ZuulServlet类中，主要代码如下：
public class ZuulServlet extends HttpServlet { private static final long serialVersionUID = -3374242278843351500L; private ZuulRunner zuulRunner; @Override public void init(ServletConfig config) throws ServletException { super.init(config); String bufferReqsStr = config.getInitParameter("buffer-requests"); boolean bufferReqs = bufferReqsStr != null && bufferReqsStr.equals("true") ? true : false; zuulRunner = new ZuulRunner(bufferReqs); } @Override public void service(javax.servlet.ServletRequest servletRequest, javax.servlet.ServletResponse servletResponse) throws ServletException, IOException { try { init((HttpServletRequest) servletRequest, (HttpServletResponse) servletResponse); // Marks this request as having passed through the "Zuul engine", as opposed to servlets // explicitly bound in web.xml, for which requests will not have the same data attached RequestContext context = RequestContext.getCurrentContext(); context.setZuulEngineRan(); try { preRoute(); //如果preRoute方法在执行的时候出现异常，直接就抛出500异常，不会走catch中的error方法，见下图FilterProcessor类中的preRoute方法。 } catch (ZuulException e) { error(e); //如果preRoute在执行过程中，抛出Zuul异常，这里被捕捉到以后，会执行error方法，打印堆栈信息，见下图FilterProcessor类中的error方法。 postRoute(); return; } try { route(); } catch (ZuulException e) { error(e); postRoute(); return; } try { postRoute(); } catch (ZuulException e) { error(e); return; } } catch (Throwable e) { error(new ZuulException(e, 500, "UNHANDLED_EXCEPTION_" + e.getClass().getName())); } finally { RequestContext.getCurrentContext().unset(); } }
//....... }
zuul一共有4种不同的生命周期：
标签：RoCE version 打印 oid div buffer ram ide out
原文地址：https://www.cnblogs.com/idoljames/p/11741382.html
