mvc:annotation-driven節點的解析器，是springmvc的核心解析器
官方注釋
Open Declaration org.springframework.web.servlet.config.AnnotationDrivenBeanDefinitionParser
A BeanDefinitionParser that provides the configuration for the <annotation-driven/> MVC namespace element.
This class registers the following <<HandlerMappings>>:
•RequestMappingHandlerMapping ordered at 0 for mapping requests to annotated controller methods.
•BeanNameUrlHandlerMapping ordered at 2 to map URL paths to controller bean names.
Note: Additional HandlerMappings may be registered as a result of using the <view-controller> or the <resources> MVC namespace elements.
This class registers the following <<HandlerAdapters>>:
•RequestMappingHandlerAdapter for processing requests with annotated controller methods.
•HttpRequestHandlerAdapter for processing requests with HttpRequestHandlers.
•SimpleControllerHandlerAdapter for processing requests with interface-based Controllers.
This class registers the following <<HandlerExceptionResolvers>>:
•ExceptionHandlerExceptionResolver for handling exceptions through @ExceptionHandler methods.
•ResponseStatusExceptionResolver for exceptions annotated with @ResponseStatus.
•DefaultHandlerExceptionResolver for resolving known Spring exception types
This class registers an org.springframework.util.<<AntPathMatcher>> and a org.springframework.web.util.<<UrlPathHelper>> to be used by:
•the RequestMappingHandlerMapping,
•the HandlerMapping for ViewControllers
•and the HandlerMapping for serving resources
Note that those beans can be configured by using the path-matching MVC namespace element.
Both the RequestMappingHandlerAdapter and the ExceptionHandlerExceptionResolver are configured with instances of the following by default:
•A ContentNegotiationManager
•A DefaultFormattingConversionService
•A org.springframework.validation.beanvalidation.LocalValidatorFactoryBean if a JSR-303 implementation is available on the classpath
•A range of HttpMessageConverters depending on what 3rd party libraries are available on the classpath.
主要注冊HandlerMappings-路徑匹配器、HandlerAdapters-路徑匹配適配器、HandlerExceptionResolvers-異常解析器、AntPathMatcher-路徑解析器、UrlPathHelper-請求路徑獲取幫助類等beans，提前為mvc做好基礎的准備
AnnotationDrivenBeanDefinitionParser#parse
從此方法中，提煉實現的最主要代碼片段，代碼如下
parserContext.registerComponent(new BeanComponentDefinition(handlerMappingDef, HANDLER_MAPPING_BEAN_NAME));
parserContext.registerComponent(new BeanComponentDefinition(handlerAdapterDef, HANDLER_ADAPTER_BEAN_NAME));
parserContext.registerComponent(new BeanComponentDefinition(uriCompContribDef, uriCompContribName));
parserContext.registerComponent(new BeanComponentDefinition(exceptionHandlerExceptionResolver, methodExceptionResolverName));
parserContext.registerComponent(new BeanComponentDefinition(responseStatusExceptionResolver, responseStatusExceptionResolverName));
parserContext.registerComponent(new BeanComponentDefinition(defaultExceptionResolver, defaultExceptionResolverName));
//格式轉換處理攔截類，比如時間、數字等
parserContext.registerComponent(new BeanComponentDefinition(mappedCsInterceptorDef, mappedInterceptorName));
// Ensure BeanNameUrlHandlerMapping (SPR-8289) and default HandlerAdapters are not "turned off"
MvcNamespaceUtils.registerDefaultComponents(parserContext, source);
跟官方注釋提及的一樣，主要目的是注冊與mvc處理有關的相關beans以及默認的mvc組件，下面我們將從以上代碼的不同組件生成進行逐個分析
HandlerMappings組件注冊
對應parse()方法的代碼片段如下
//生成RequestMappingHandlerMapping組件對象
RootBeanDefinition handlerMappingDef = new RootBeanDefinition(RequestMappingHandlerMapping.class);
handlerMappingDef.setSource(source);
handlerMappingDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
//優先級設置為最高
handlerMappingDef.getPropertyValues().add("order", 0);
//添加contentNegotiationManager屬性，處理media type handlerMappingDef.getPropertyValues().add("contentNegotiationManager", contentNegotiationManager);
//查看mvc:annotation-driven有無enable-matrix-variables/enableMatrixVariables，表示是否開啟多變量映射比如/cars;a=1;b=1
//具體使用可查閱相關文檔，默認removeSemicolonContent為false
if (element.hasAttribute("enable-matrix-variables")) {
Boolean enableMatrixVariables = Boolean.valueOf(element.getAttribute("enable-matrix-variables"));
handlerMappingDef.getPropertyValues().add("removeSemicolonContent", !enableMatrixVariables);
}
else if (element.hasAttribute("enableMatrixVariables")) {
Boolean enableMatrixVariables = Boolean.valueOf(element.getAttribute("enableMatrixVariables"));
handlerMappingDef.getPropertyValues().add("removeSemicolonContent", !enableMatrixVariables);
}
//配置路徑匹配解析器等屬性
configurePathMatchingProperties(handlerMappingDef, element, parserContext);
//將RequestMappingHandlerMapping注冊為bean對象放置bean工廠中 readerContext.getRegistry().registerBeanDefinition(HANDLER_MAPPING_BEAN_NAME , handlerMappingDef);
RequestMappingHandlerMapping主要是處理@Controller和@RequestMapping注解的，另外再看下configurePathMatchingProperties()配置路徑解析器方法
AnnotationDrivenBeanDefinitionParser#configurePathMatchingProperties-路徑匹配解析器配置
代碼如下
private void configurePathMatchingProperties(RootBeanDefinition handlerMappingDef, Element element,
ParserContext parserContext) {
//獲取mvc:annotation-driven下子節點mvc:path-matching
Element pathMatchingElement = DomUtils.getChildElementByTagName(element, "path-matching");
if (pathMatchingElement != null) {
Object source = parserContext.extractSource(element);
//是否采用suffix-pattern，即.*,比如/user也匹配/user.*。默認為true
if (pathMatchingElement.hasAttribute("suffix-pattern")) {
Boolean useSuffixPatternMatch = Boolean.valueOf(pathMatchingElement.getAttribute("suffix-pattern"));
handlerMappingDef.getPropertyValues().add("useSuffixPatternMatch", useSuffixPatternMatch);
}
//是否采用分隔符，特指/，比如/user也匹配/user/。默認為true
if (pathMatchingElement.hasAttribute("trailing-slash")) {
Boolean useTrailingSlashMatch = Boolean.valueOf(pathMatchingElement.getAttribute("trailing-slash"));
handlerMappingDef.getPropertyValues().add("useTrailingSlashMatch", useTrailingSlashMatch);
}
//是否采用contentNegotiationManager中的格式，比如*.json/*.xml。默認為false
if (pathMatchingElement.hasAttribute("registered-suffixes-only")) {
Boolean useRegisteredSuffixPatternMatch = Boolean.valueOf(pathMatchingElement.getAttribute("registered-suffixes-only"));
handlerMappingDef.getPropertyValues().add("useRegisteredSuffixPatternMatch", useRegisteredSuffixPatternMatch);
}
RuntimeBeanReference pathHelperRef = null;
//路徑解析幫助類，可指定，默認為UrlPathHelper
if (pathMatchingElement.hasAttribute("path-helper")) {
pathHelperRef = new RuntimeBeanReference(pathMatchingElement.getAttribute("path-helper"));
}
pathHelperRef = MvcNamespaceUtils.registerUrlPathHelper(pathHelperRef, parserContext, source);
handlerMappingDef.getPropertyValues().add("urlPathHelper", pathHelperRef);
RuntimeBeanReference pathMatcherRef = null;
//路徑解析器，默認為AntPathMatcher解析器
if (pathMatchingElement.hasAttribute("path-matcher")) {
pathMatcherRef = new RuntimeBeanReference(pathMatchingElement.getAttribute("path-matcher"));
}
pathMatcherRef = MvcNamespaceUtils.registerPathMatcher(pathMatcherRef, parserContext, source);
handlerMappingDef.getPropertyValues().add("pathMatcher", pathMatcherRef);
}
}
看代碼邏輯，主要是通過mvc:annotation-driven下的mvc:path-matching節點來配置
- suffix-pattern-是否啟用后綴匹配，默認為true，即對指定的url會再新增
.*，比如/user實際匹配/user.*->/user匹配/user.html,/user.jsp- trailing-slash-是否啟動尾部斜線匹配，默認為true，即對指定的url會新增
/，比如/user也會匹配/user/- registered-suffixes-only-是否啟用media type類型的匹配，即對指定的url新增
*.json/*.xml等匹配，默認為false- path-helper-路徑獲取幫助類，默認為UrlPathHelper類
- path-matcher-路徑匹配解析器，默認為AntPathMather
HandlerAdapters組件注冊
相應的代碼片段如下
//獲取conversion-service屬性，默認為FormattingConversionServiceFactoryBean
//處理一些基本類的格式與轉換，比如時間、數字等
RuntimeBeanReference conversionService = getConversionService(element, source, parserContext);
//獲取validator,默認為OptionalValidatorFactoryBean，基於java自帶的Validator接口，表示校驗器，可用於javabean的參數校驗等
RuntimeBeanReference validator = getValidator(element, source, parserContext);
//獲取message-codes-resolver屬性，默認為null。
RuntimeBeanReference messageCodesResolver = getMessageCodesResolver(element);
//設置ConfigurableWebBindingInitializer類 用於數據綁定
RootBeanDefinition bindingDef = new RootBeanDefinition(ConfigurableWebBindingInitializer.class);
bindingDef.setSource(source);
bindingDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
bindingDef.getPropertyValues().add("conversionService", conversionService);
bindingDef.getPropertyValues().add("validator", validator);
bindingDef.getPropertyValues().add("messageCodesResolver", messageCodesResolver);
//獲取message-converters子節點的配置，消息轉換器，可用於向前端發送數據再次自定義組裝
//比如MappingJackson2HttpMessageConverter json轉字符串
ManagedList<?> messageConverters = getMessageConverters(element, source, parserContext);
//argument-resolvers子節點配置，參數解析
ManagedList<?> argumentResolvers = getArgumentResolvers(element, parserContext);
//return-value-handlers子節點解析
ManagedList<?> returnValueHandlers = getReturnValueHandlers(element, parserContext);
//async-support子節點解析，獲取其中的default-timeout屬性，作為異步處理超時時間，默認null
String asyncTimeout = getAsyncTimeout(element);
//async-support子節點解析，獲取其中的task-executor屬性。異步任務線程池
RuntimeBeanReference asyncExecutor = getAsyncExecutor(element);
//async-support子節點解析，獲取其中的callable-interceptors節點。異步處理callable類型攔截器
ManagedList<?> callableInterceptors = getCallableInterceptors(element, source, parserContext);
ManagedList<?> deferredResultInterceptors = getDeferredResultInterceptors(element, source, parserContext);
//將上述的屬性添加到RequestMappingHandlerAdapter中
RootBeanDefinition handlerAdapterDef = new RootBeanDefinition(RequestMappingHandlerAdapter.class);
handlerAdapterDef.setSource(source);
handlerAdapterDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
handlerAdapterDef.getPropertyValues().add("contentNegotiationManager", contentNegotiationManager);
handlerAdapterDef.getPropertyValues().add("webBindingInitializer", bindingDef);
handlerAdapterDef.getPropertyValues().add("messageConverters", messageConverters);
addRequestBodyAdvice(handlerAdapterDef);
addResponseBodyAdvice(handlerAdapterDef);
//ignoreDefaultModelOnRedirect屬性配置
if (element.hasAttribute("ignore-default-model-on-redirect")) {
Boolean ignoreDefaultModel = Boolean.valueOf(element.getAttribute("ignore-default-model-on-redirect"));
handlerAdapterDef.getPropertyValues().add("ignoreDefaultModelOnRedirect", ignoreDefaultModel);
}
else if (element.hasAttribute("ignoreDefaultModelOnRedirect")) {
// "ignoreDefaultModelOnRedirect" spelling is deprecated
Boolean ignoreDefaultModel = Boolean.valueOf(element.getAttribute("ignoreDefaultModelOnRedirect"));
handlerAdapterDef.getPropertyValues().add("ignoreDefaultModelOnRedirect", ignoreDefaultModel);
}
if (argumentResolvers != null) {
handlerAdapterDef.getPropertyValues().add("customArgumentResolvers", argumentResolvers);
}
if (returnValueHandlers != null) {
handlerAdapterDef.getPropertyValues().add("customReturnValueHandlers", returnValueHandlers);
}
if (asyncTimeout != null) {
handlerAdapterDef.getPropertyValues().add("asyncRequestTimeout", asyncTimeout);
}
if (asyncExecutor != null) {
handlerAdapterDef.getPropertyValues().add("taskExecutor", asyncExecutor);
}
handlerAdapterDef.getPropertyValues().add("callableInterceptors", callableInterceptors);
handlerAdapterDef.getPropertyValues().add("deferredResultInterceptors", deferredResultInterceptors);
readerContext.getRegistry().registerBeanDefinition(HANDLER_ADAPTER_BEAN_NAME , handlerAdapterDef);
配置的主要是
RequestMappingHandlerAdapter對象，其中的屬性較多，讀者可查看>>>SpringMVC源碼情操陶冶-RequestMappingHandlerAdapter適配器。其主要支持HandlerMethod類，而這些類都是由RequestMappingHandlerMapping來生成的，而這又是通過AbstractHandlerMethodMapping#initHandlerMethods來實現的，有興趣的可以自行去查閱
ExceptionResolver組件注冊
默認采用ExceptionHandlerExceptionResolver、ResponseStatusExceptionResolver、DefaultHandlerExceptionResolver作為異常處理類
RootBeanDefinition exceptionHandlerExceptionResolver = new RootBeanDefinition(ExceptionHandlerExceptionResolver.class);
exceptionHandlerExceptionResolver.setSource(source);
exceptionHandlerExceptionResolver.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
exceptionHandlerExceptionResolver.getPropertyValues().add("contentNegotiationManager", contentNegotiationManager);
exceptionHandlerExceptionResolver.getPropertyValues().add("messageConverters", messageConverters);
exceptionHandlerExceptionResolver.getPropertyValues().add("order", 0);
addResponseBodyAdvice(exceptionHandlerExceptionResolver);
String methodExceptionResolverName = readerContext.registerWithGeneratedName(exceptionHandlerExceptionResolver);
RootBeanDefinition responseStatusExceptionResolver = new RootBeanDefinition(ResponseStatusExceptionResolver.class);
responseStatusExceptionResolver.setSource(source);
responseStatusExceptionResolver.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
responseStatusExceptionResolver.getPropertyValues().add("order", 1);
String responseStatusExceptionResolverName =
readerContext.registerWithGeneratedName(responseStatusExceptionResolver);
RootBeanDefinition defaultExceptionResolver = new RootBeanDefinition(DefaultHandlerExceptionResolver.class);
defaultExceptionResolver.setSource(source);
defaultExceptionResolver.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
defaultExceptionResolver.getPropertyValues().add("order", 2);
String defaultExceptionResolverName =
readerContext.registerWithGeneratedName(defaultExceptionResolver);
ExceptionHandlerExceptionResolver-處理
@ExceptionHandler方法注解ResponseStatusExceptionResolver-處理
@ResponseStatus類型、方法注解DefaultHandlerExceptionResolver-處理普通的spring異常
更准確的可查看官方注釋說明
小結
mvc:annotation-driven一句話便囊括了springmvc的基本處理組件注冊成bean到springmvc上下文，結合此處再去理解springmvc的邏輯源碼就簡單了