zuul各版本实现存在一些微小的变化，总的实现思想未改变，以spring-cloud-netflix-core-1.3.6.RELEASE为例
一、zuul的重要的初始化类
org.springframework.cloud.netflix.zuul.ZuulServerAutoConfiguration
org.springframework.cloud.netflix.zuul.ZuulProxyAutoConfiguration
org.springframework.cloud.netflix.zuul.ZuulFilterInitializer
org.springframework.cloud.netflix.zuul.RibbonCommandFactoryConfiguration
ZuulServerAutoConfiguration
初始化路由规则
初始化一些重要的filter如 PreDecorationFilter，RibbonRoutingFilter
初始化ZuulFilterInitializer
初始化ZuulHandlerMapping
代码如下
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
|
//路由规则 @Bean@ConditionalOnMissingBean(DiscoveryClientRouteLocator.class)public DiscoveryClientRouteLocator discoveryRouteLocator() {return new DiscoveryClientRouteLocator(this.server.getServletPrefix(), this.discovery, this.zuulProperties, this.serviceRouteMapper);} // pre filters@Beanpublic PreDecorationFilter preDecorationFilter(RouteLocator routeLocator, ProxyRequestHelper proxyRequestHelper) {return new PreDecorationFilter(routeLocator, this.server.getServletPrefix(), this.zuulProperties, proxyRequestHelper);}// route filters@Beanpublic RibbonRoutingFilter ribbonRoutingFilter(ProxyRequestHelper helper, RibbonCommandFactory<?> ribbonCommandFactory) {RibbonRoutingFilter filter = new RibbonRoutingFilter(helper, ribbonCommandFactory, this.requestCustomizers);return filter;} @Configurationprotected static class ZuulFilterConfiguration {@Autowiredprivate Map<String, ZuulFilter> filters;@Beanpublic ZuulFilterInitializer zuulFilterInitializer( CounterFactory counterFactory, TracerFactory tracerFactory) { FilterLoader filterLoader = FilterLoader.getInstance(); FilterRegistry filterRegistry = FilterRegistry.instance(); return new ZuulFilterInitializer(this.filters, counterFactory, tracerFactory, filterLoader, filterRegistry);}}@Beanpublic ZuulController zuulController() {return new ZuulController();}@Beanpublic ZuulHandlerMapping zuulHandlerMapping(RouteLocator routes) {ZuulHandlerMapping mapping = new ZuulHandlerMapping(routes, zuulController());mapping.setErrorController(this.errorController);return mapping;} |
ZuulProxyAutoConfiguration
zuulProxAutoConfiguration继承ZuulServerAutoConfiguration功能上和zuulServerAutoConfiguration
主要功能是增加了RibbonCommandFactoryConfiguration的配置，初始化所有的实现ribbon的方式如apache,okhttp。
ZuulFilterInitializer
该类的作用主要是把初始化的过滤器注册到zuul的FilterRegistry，FilterRegistry是一个单例用于初始化路由信息，在ZuulRunner中使用
RibbonCommandFactoryConfiguration
主要作用是配置转发的实现，实现主要有apache，okhttp
二、zuul的转发实现
首先第一步转到ZuulHandlerMapping中的lookupHandler方法，把转发转到zuulController中
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
|
@Override protected Object lookupHandler(String urlPath, HttpServletRequest request) throws Exception { if (this.errorController != null && urlPath.equals(this.errorController.getErrorPath())) { return null; } String[] ignored = this.routeLocator.getIgnoredPaths().toArray(new String[0]); if (PatternMatchUtils.simpleMatch(ignored, urlPath)) { return null; } RequestContext ctx = RequestContext.getCurrentContext(); if (ctx.containsKey("forward.to")) { return null; } if (this.dirty) { synchronized (this) { if (this.dirty) { registerHandlers(); this.dirty = false; } } } return super.lookupHandler(urlPath, request); } |
第一次访问时dirty为true会初始化一次请求规则如下
|
1
2
3
4
5
6
7
8
9
10
11
|
private void registerHandlers() { Collection<Route> routes = this.routeLocator.getRoutes(); if (routes.isEmpty()) { this.logger.warn("No routes found from RouteLocator"); } else { for (Route route : routes) { registerHandler(route.getFullPath(), this.zuul); } } } |
第二步ZuulController继承ServletWrappingController的会把请求转到ZuulServlet中如下
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
|
/** * @author Spencer Gibb */public class ZuulController extends ServletWrappingController { public ZuulController() { setServletClass(ZuulServlet.class); setServletName("zuul"); setSupportedMethods((String[]) null); // Allow all } @Override public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception { try { // We don't care about the other features of the base class, just want to // handle the request return super.handleRequestInternal(request, response); } finally { // @see com.netflix.zuul.context.ContextLifecycleFilter.doFilter RequestContext.getCurrentContext().unset(); } }} |
第三步ZuulServlet的service方法如下主要执行pre,route,postRoute三种路由器
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
|
@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(); } catch (ZuulException e) { error(e); 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(); } } |
四、最后由SendResponseFilter执行返回结果,filterOrder为1000所以最好post的filter不要超过1000否则影响返回结果
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://my.oschina.net/u/136848/blog/1621259
