@Configuration
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass({
Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class })
@ConditionalOnMissingBean(WebMvcConfigurationSupport.class)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
@AutoConfigureAfter({
DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class,
ValidationAutoConfiguration.class })
public class WebMvcAutoConfiguration {
}
1、WebMvcAutoConfigurationAdapter
@Configuration
@Import(EnableWebMvcConfiguration.class)
@EnableConfigurationProperties({
WebMvcProperties.class, ResourceProperties.class })
@Order(0)
public static class WebMvcAutoConfigurationAdapter implements WebMvcConfigurer, ResourceLoaderAware {
...
public WebMvcAutoConfigurationAdapter(ResourceProperties resourceProperties, WebMvcProperties mvcProperties,
ListableBeanFactory beanFactory, ObjectProvider<HttpMessageConverters> messageConvertersProvider,
ObjectProvider<ResourceHandlerRegistrationCustomizer> resourceHandlerRegistrationCustomizerProvider) {
this.resourceProperties = resourceProperties;
this.mvcProperties = mvcProperties;
this.beanFactory = beanFactory;
this.messageConvertersProvider = messageConvertersProvider;
this.resourceHandlerRegistrationCustomizer = resourceHandlerRegistrationCustomizerProvider.getIfAvailable();
}
...
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
this.messageConvertersProvider
.ifAvailable((customConverters) -> converters.addAll(customConverters.getConverters()));
}
...
@Override
public void configurePathMatch(PathMatchConfigurer configurer) {
configurer.setUseSuffixPatternMatch(this.mvcProperties.getPathmatch().isUseSuffixPattern());
configurer.setUseRegisteredSuffixPatternMatch(
this.mvcProperties.getPathmatch().isUseRegisteredSuffixPattern());
}
...
@Bean
@ConditionalOnMissingBean
public InternalResourceViewResolver defaultViewResolver() {
InternalResourceViewResolver resolver = new InternalResourceViewResolver();
resolver.setPrefix(this.mvcProperties.getView().getPrefix());
resolver.setSuffix(this.mvcProperties.getView().getSuffix());
return resolver;
}
@Bean
@ConditionalOnBean(View.class)
@ConditionalOnMissingBean
public BeanNameViewResolver beanNameViewResolver() {
BeanNameViewResolver resolver = new BeanNameViewResolver();
resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 10);
return resolver;
}
@Bean
@ConditionalOnBean(ViewResolver.class)
@ConditionalOnMissingBean(name = "viewResolver", value = ContentNegotiatingViewResolver.class)
public ContentNegotiatingViewResolver viewResolver(BeanFactory beanFactory) {
ContentNegotiatingViewResolver resolver = new ContentNegotiatingViewResolver();
resolver.setContentNegotiationManager(beanFactory.getBean(ContentNegotiationManager.class));
resolver.setOrder(Ordered.HIGHEST_PRECEDENCE);
return resolver;
}
@Bean
@ConditionalOnMissingBean
@ConditionalOnProperty(prefix = "spring.mvc", name = "locale")
public LocaleResolver localeResolver() {
if (this.mvcProperties.getLocaleResolver() == WebMvcProperties.LocaleResolver.FIXED) {
return new FixedLocaleResolver(this.mvcProperties.getLocale());
}
AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver();
localeResolver.setDefaultLocale(this.mvcProperties.getLocale());
return localeResolver;
}
...
private <T> Collection<T> getBeansOfType(Class<T> type) {
return this.beanFactory.getBeansOfType(type).values();
}
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
Duration cachePeriod = this.resourceProperties.getCache().getPeriod();
CacheControl cacheControl = this.resourceProperties.getCache().getCachecontrol().toHttpCacheControl();
if (!registry.hasMappingForPattern("/webjars/**")) {
customizeResourceHandlerRegistration(registry.addResourceHandler("/webjars/**")
.addResourceLocations("classpath:/META-INF/resources/webjars/")
.setCachePeriod(getSeconds(cachePeriod)).setCacheControl(cacheControl));
}
String staticPathPattern = this.mvcProperties.getStaticPathPattern();
if (!registry.hasMappingForPattern(staticPathPattern)) {
customizeResourceHandlerRegistration(registry.addResourceHandler(staticPathPattern)
.addResourceLocations(getResourceLocations(this.resourceProperties.getStaticLocations()))
.setCachePeriod(getSeconds(cachePeriod)).setCacheControl(cacheControl));
}
}
...
static String[] getResourceLocations(String[] staticLocations) {
String[] locations = new String[staticLocations.length + SERVLET_LOCATIONS.length];
System.arraycopy(staticLocations, 0, locations, 0, staticLocations.length);
System.arraycopy(SERVLET_LOCATIONS, 0, locations, staticLocations.length, SERVLET_LOCATIONS.length);
return locations;
}
...
private void customizeResourceHandlerRegistration(ResourceHandlerRegistration registration) {
if (this.resourceHandlerRegistrationCustomizer != null) {
this.resourceHandlerRegistrationCustomizer.customize(registration);
}
}
@Bean
@ConditionalOnMissingBean({
RequestContextListener.class, RequestContextFilter.class })
@ConditionalOnMissingFilterBean(RequestContextFilter.class)
public static RequestContextFilter requestContextFilter() {
return new OrderedRequestContextFilter();
}
...
}
2、EnableWebMvcConfiguration
等价于 @EnableWebMvc 注解。
@Configuration
public static class EnableWebMvcConfiguration extends DelegatingWebMvcConfiguration {
private final WebMvcProperties mvcProperties;
private final ListableBeanFactory beanFactory;
private final WebMvcRegistrations mvcRegistrations;
public EnableWebMvcConfiguration(ObjectProvider<WebMvcProperties> mvcPropertiesProvider,
ObjectProvider<WebMvcRegistrations> mvcRegistrationsProvider, ListableBeanFactory beanFactory) {
this.mvcProperties = mvcPropertiesProvider.getIfAvailable();
this.mvcRegistrations = mvcRegistrationsProvider.getIfUnique();
this.beanFactory = beanFactory;
}
@Bean
@Override
public RequestMappingHandlerAdapter requestMappingHandlerAdapter() {
RequestMappingHandlerAdapter adapter = super.requestMappingHandlerAdapter();
adapter.setIgnoreDefaultModelOnRedirect(
this.mvcProperties == null || this.mvcProperties.isIgnoreDefaultModelOnRedirect());
return adapter;
}
@Override
protected RequestMappingHandlerAdapter createRequestMappingHandlerAdapter() {
if (this.mvcRegistrations != null && this.mvcRegistrations.getRequestMappingHandlerAdapter() != null) {
return this.mvcRegistrations.getRequestMappingHandlerAdapter();
}
return super.createRequestMappingHandlerAdapter();
}
@Bean
@Primary
@Override
public RequestMappingHandlerMapping requestMappingHandlerMapping() {
// Must be @Primary for MvcUriComponentsBuilder to work
return super.requestMappingHandlerMapping();//WebMvcConfigurationSupport#requestMappingHandlerMapping
}
...
@Bean
@Override
public Validator mvcValidator() {
if (!ClassUtils.isPresent("javax.validation.Validator", getClass().getClassLoader())) {
return super.mvcValidator();
}
return ValidatorAdapter.get(getApplicationContext(), getValidator());
}
@Override
protected RequestMappingHandlerMapping createRequestMappingHandlerMapping() {
if (this.mvcRegistrations != null && this.mvcRegistrations.getRequestMappingHandlerMapping() != null) {
return this.mvcRegistrations.getRequestMappingHandlerMapping();
}
//WebMvcConfigurationSupport#createRequestMappingHandlerMapping
return super.createRequestMappingHandlerMapping();
}
@Override
protected ConfigurableWebBindingInitializer getConfigurableWebBindingInitializer() {
try {
return this.beanFactory.getBean(ConfigurableWebBindingInitializer.class);
}
catch (NoSuchBeanDefinitionException ex) {
return super.getConfigurableWebBindingInitializer();
}
}
...
@Override
protected void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {
super.configureHandlerExceptionResolvers(exceptionResolvers);
if (exceptionResolvers.isEmpty()) {
addDefaultHandlerExceptionResolvers(exceptionResolvers);
}
if (this.mvcProperties.isLogResolvedException()) {
for (HandlerExceptionResolver resolver : exceptionResolvers) {
if (resolver instanceof AbstractHandlerExceptionResolver) {
((AbstractHandlerExceptionResolver) resolver).setWarnLogCategory(resolver.getClass().getName());
}
}
}
}
@Bean
@Override
public ContentNegotiationManager mvcContentNegotiationManager() {
ContentNegotiationManager manager = super.mvcContentNegotiationManager();
List<ContentNegotiationStrategy> strategies = manager.getStrategies();
ListIterator<ContentNegotiationStrategy> iterator = strategies.listIterator();
while (iterator.hasNext()) {
ContentNegotiationStrategy strategy = iterator.next();
if (strategy instanceof PathExtensionContentNegotiationStrategy) {
iterator.set(new OptionalPathExtensionContentNegotiationStrategy(strategy));
}
}
return manager;
}
}
DelegatingWebMvcConfiguration是WebMvcConfigurationSupport的子类。
3、WebMvcConfigurationSupport
这个类的作用是通过 Java Config配置方式给服务提供MVC功能。核心功能是初始化SpringMVC中九大组件之HandlerMapping、HandlerAdapter。
public RequestMappingHandlerMapping requestMappingHandlerMapping() {
//EnableWebMvcConfiguration#createRequestMappingHandlerMapping
RequestMappingHandlerMapping mapping = createRequestMappingHandlerMapping();
mapping.setOrder(0);
mapping.setInterceptors(getInterceptors());//用户自定义拦截器
mapping.setContentNegotiationManager(mvcContentNegotiationManager());
mapping.setCorsConfigurations(getCorsConfigurations());
PathMatchConfigurer configurer = getPathMatchConfigurer();
Boolean useSuffixPatternMatch = configurer.isUseSuffixPatternMatch();
if (useSuffixPatternMatch != null) {
mapping.setUseSuffixPatternMatch(useSuffixPatternMatch);
}
Boolean useRegisteredSuffixPatternMatch = configurer.isUseRegisteredSuffixPatternMatch();
if (useRegisteredSuffixPatternMatch != null) {
mapping.setUseRegisteredSuffixPatternMatch(useRegisteredSuffixPatternMatch);
}
Boolean useTrailingSlashMatch = configurer.isUseTrailingSlashMatch();
if (useTrailingSlashMatch != null) {
mapping.setUseTrailingSlashMatch(useTrailingSlashMatch);
}
UrlPathHelper pathHelper = configurer.getUrlPathHelper();
if (pathHelper != null) {
mapping.setUrlPathHelper(pathHelper);
}
PathMatcher pathMatcher = configurer.getPathMatcher();
if (pathMatcher != null) {
mapping.setPathMatcher(pathMatcher);
}
Map<String, Predicate<Class<?>>> pathPrefixes = configurer.getPathPrefixes();
if (pathPrefixes != null) {
mapping.setPathPrefixes(pathPrefixes);
}
return mapping;
}
protected RequestMappingHandlerMapping createRequestMappingHandlerMapping() {
return new RequestMappingHandlerMapping();
}
3.1、RequestMappingHandlerMapping
RequestMappingHandlerMapping在初始化过程中存在拦截器、路由匹配规则等功能的初始化。
4、EnableWebMvc注解
该注解通过@Import生成 WebMvcConfigurationSupport 类的子类 DelegatingWebMvcConfiguration。
首先该注解的存在将导致WebMvcAutoConfiguration无法自动初始化，也即意味着WebMvcAutoConfiguration类中初始化RequestMappingHandlerMapping等SpringMVC组件的功能需要自己实现。