当请求形如：/opendoc/jquery-1.10.2.min.js 的静态资源时，如果恰好存在匹配这个请求的Controller时，默认情况下，这个静态资源请求会被 RequestMappingHandlerMapping 分配给这个Controller处理，从而可能找不到静态资源，例如存在下面这样的Controller：
@RequestMapping(value = "/{name}/{version}", method = {RequestMethod.POST, RequestMethod.GET})
public void rest3(@PathVariable("name") String name, @PathVariable("version") String version,
HttpServletRequest request, HttpServletResponse response) {
this.doRest(name, version, request, response);
}
为了能正确匹配的静态资源，我们可以调整Spring HandlerMapping的顺序，让SimpleUrlHandlerMapping先于RequestMappingHandlerMapping去匹配请求，SimpleUrlHandlerMapping会返回一个用于加载静态资源的ResourceHttpRequestHandler
默认情况下RequestMappingHandlerMapping 先于SimpleUrlHandlerMapping匹配请求，DispatcherServlet中初始化HandlerMapping的顺序源码如下所示：
/**
* Initialize the HandlerMappings used by this class.
* <p>If no HandlerMapping beans are defined in the BeanFactory for this namespace,
* we default to BeanNameUrlHandlerMapping.
*/
private void initHandlerMappings(ApplicationContext context) {
this.handlerMappings = null;
if (this.detectAllHandlerMappings) {
// Find all HandlerMappings in the ApplicationContext, including ancestor contexts.
Map<String, HandlerMapping> matchingBeans =
BeanFactoryUtils.beansOfTypeIncludingAncestors(context, HandlerMapping.class, true, false);
if (!matchingBeans.isEmpty()) {
this.handlerMappings = new ArrayList<>(matchingBeans.values());
// We keep HandlerMappings in sorted order.
AnnotationAwareOrderComparator.sort(this.handlerMappings);
}
}
else {
try {
HandlerMapping hm = context.getBean(HANDLER_MAPPING_BEAN_NAME, HandlerMapping.class);
this.handlerMappings = Collections.singletonList(hm);
}
catch (NoSuchBeanDefinitionException ex) {
// Ignore, we'll add a default HandlerMapping later.
}
}
// Ensure we have at least one HandlerMapping, by registering
// a default HandlerMapping if no other mappings are found.
if (this.handlerMappings == null) {
this.handlerMappings = getDefaultStrategies(context, HandlerMapping.class);
if (logger.isTraceEnabled()) {
logger.trace("No HandlerMappings declared for servlet '" + getServletName() +
"': using default strategies from DispatcherServlet.properties");
}
}
}
默认情况下RequestMappingHandlerMapping 先于SimpleUrlHandlerMapping匹配请求：
调整HandlerMapping顺序：
@Configuration
public class WebConfiguration extends WebMvcConfigurationSupport {
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry){
registry.addResourceHandler("/opendoc/**").addResourceLocations("/opendoc/");
registry.setOrder(0);
}
@Override
@Bean
public RequestMappingHandlerMapping requestMappingHandlerMapping(ContentNegotiationManager contentNegotiationManager, FormattingConversionService conversionService, ResourceUrlProvider resourceUrlProvider) {
RequestMappingHandlerMapping handler = super.requestMappingHandlerMapping(contentNegotiationManager, conversionService, resourceUrlProvider);
handler.setOrder(1);
return handler;
}
}
order值越小，优先级越高。
调整之后的HandlerMapping顺序：
此时，SimpleUrlHandlerMapping会返回一个用于加载静态资源的ResourceHttpRequestHandler
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