HandlerMappingIntrospector的initHandlerMappings()具体逻辑如下:
private static List<HandlerMapping> initHandlerMappings(ApplicationContext applicationContext) {
Map<String, HandlerMapping> beans = BeanFactoryUtils.beansOfTypeIncludingAncestors(
applicationContext, HandlerMapping.class, true, false);
if (!beans.isEmpty()) {
List<HandlerMapping> mappings = new ArrayList<>(beans.values());
AnnotationAwareOrderComparator.sort(mappings);
return Collections.unmodifiableList(mappings);
}
return Collections.unmodifiableList(initFallback(applicationContext));
}
能够看到beans的数量为8,此时HandlerMappingIntrospector.handlerMappings属性值曾经被赋值了。
private void filterAndRecordMetrics(HttpServletRequest request,
HttpServletResponse response, FilterChain filterChain)
throws IOException, ServletException {
Object handler;
try {
handler = getHandler(request);//1
}
catch (Exception ex) {
logger.debug("Unable to time request", ex);
filterChain.doFilter(request, response);
return;
}
//
filterAndRecordMetrics(request, response, filterChain, handler);
}
第1处获取HandlerMethod;第2处,继续执行doFilter()办法,最终在MockFilterChain.doFilter()执行到DispatcherServlet.doDispatch(request, response);
其中mappedHandler = getHandler(processedRequest);获取HandlerExecutionChain。
Determine handler adapter for the current request.
HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());
在下面codwe块中获取适合的HandlerAdapter。
中依据mappedHandler失去HandlerMethod
中根据HandlerMethod利用反射技术去调用指标类,取得返回值。
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