springMVC源码研究--初识篇1 / 2（springboot 自动化配置springMVC以及mvc初始化机制）
最近使用springboot 做微服务开发，对外提供的都是http接口，那么就来研究下springMvc。
Servlet 是web容器对http请求进行处理的基本集成单元，应用程序处理的所有请求都是通过servlet转发controller里面对应的方法上的， 那么：
springboot是怎么样自动配置启用了springMvc功能？
springmvc是怎么做到的接受servlet转发的请求？
springMvc 是如何实现将请求与处理逻辑进行绑定的？
首先，我们开发中使用了springboot的自动化配置，maven依赖中可以找到
org.springframework.boot
spring-boot-autoconfigure
2.1.6.RELEASE
该依赖中可以看到spring.factories文件，如下：
# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\
org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration,\
org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration,\
org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,\
org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration,\
org.springframework.boot.autoconfigure.cloud.CloudServiceConnectorsAutoConfiguration,\
org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,\
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration,\
org.springframework.boot.autoconfigure.couchbase.CouchbaseAutoConfiguration,\
org.springframework.boot.autoconfigure.dao.PersistenceExceptionTranslationAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.jdbc.JdbcRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.ldap.LdapRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.solr.SolrRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.rest.RepositoryRestMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.data.web.SpringDataWebAutoConfiguration,\
org.springframework.boot.autoconfigure.elasticsearch.jest.JestAutoConfiguration,\
org.springframework.boot.autoconfigure.elasticsearch.rest.RestClientAutoConfiguration,\
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration,\
org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration,\
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration,\
org.springframework.boot.autoconfigure.h2.H2ConsoleAutoConfiguration,\
org.springframework.boot.autoconfigure.hateoas.HypermediaAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastJpaDependencyAutoConfiguration,\
org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration,\
org.springframework.boot.autoconfigure.http.codec.CodecsAutoConfiguration,\
org.springframework.boot.autoconfigure.influx.InfluxDbAutoConfiguration,\
org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration,\
org.springframework.boot.autoconfigure.integration.IntegrationAutoConfiguration,\
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.XADataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JmsAutoConfiguration,\
org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JndiConnectionFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.activemq.ActiveMQAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.artemis.ArtemisAutoConfiguration,\
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration,\
org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration,\
org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration,\
org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration,\
org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapAutoConfiguration,\
org.springframework.boot.autoconfigure.ldap.LdapAutoConfiguration,\
org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderValidatorAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.MongoReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration,\
org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration,\
org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration,\
org.springframework.boot.autoconfigure.reactor.core.ReactorCoreAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityRequestMatcherProviderAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.UserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityFilterAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveUserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.sendgrid.SendGridAutoConfiguration,\
org.springframework.boot.autoconfigure.session.SessionAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.client.servlet.OAuth2ClientAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.client.reactive.ReactiveOAuth2ClientAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.resource.servlet.OAuth2ResourceServerAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.resource.reactive.ReactiveOAuth2ResourceServerAutoConfiguration,\
org.springframework.boot.autoconfigure.solr.SolrAutoConfiguration,\
org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration,\
org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration,\
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.jta.JtaAutoConfiguration,\
org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration,\
org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.HttpHandlerAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.ReactiveWebServerFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.error.ErrorWebFluxAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.function.client.ClientHttpConnectorAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration,\
等等。。。。。我们会找到 org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration 这个自动化配置类
类名解读：MVC自动配置类
/*
* Copyright 2012-2019 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.boot.autoconfigure.web.servlet;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;
import java.util.Optional;
import javax.servlet.Servlet;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.AutoConfigureOrder;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
import org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration;
import org.springframework.boot.autoconfigure.template.TemplateAvailabilityProviders;
import org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration;
import org.springframework.boot.autoconfigure.validation.ValidatorAdapter;
import org.springframework.boot.autoconfigure.web.ConditionalOnEnabledResourceChain;
import org.springframework.boot.autoconfigure.web.ResourceProperties;
import org.springframework.boot.autoconfigure.web.ResourceProperties.Strategy;
import org.springframework.boot.autoconfigure.web.format.WebConversionService;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.web.servlet.filter.OrderedFormContentFilter;
import org.springframework.boot.web.servlet.filter.OrderedHiddenHttpMethodFilter;
import org.springframework.boot.web.servlet.filter.OrderedRequestContextFilter;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.Primary;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.core.convert.converter.Converter;
import org.springframework.core.convert.converter.GenericConverter;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.task.AsyncTaskExecutor;
import org.springframework.format.Formatter;
import org.springframework.format.FormatterRegistry;
import org.springframework.format.support.FormattingConversionService;
import org.springframework.http.CacheControl;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.util.ClassUtils;
import org.springframework.validation.DefaultMessageCodesResolver;
import org.springframework.validation.MessageCodesResolver;
import org.springframework.validation.Validator;
import org.springframework.web.HttpMediaTypeNotAcceptableException;
import org.springframework.web.accept.ContentNegotiationManager;
import org.springframework.web.accept.ContentNegotiationStrategy;
import org.springframework.web.accept.PathExtensionContentNegotiationStrategy;
import org.springframework.web.bind.support.ConfigurableWebBindingInitializer;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextListener;
import org.springframework.web.filter.FormContentFilter;
import org.springframework.web.filter.HiddenHttpMethodFilter;
import org.springframework.web.filter.RequestContextFilter;
import org.springframework.web.servlet.DispatcherServlet;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.AsyncSupportConfigurer;
import org.springframework.web.servlet.config.annotation.ContentNegotiationConfigurer;
import org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.PathMatchConfigurer;
import org.springframework.web.servlet.config.annotation.ResourceChainRegistration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver;
import org.springframework.web.servlet.handler.SimpleUrlHandlerMapping;
import org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver;
import org.springframework.web.servlet.i18n.FixedLocaleResolver;
import org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
import org.springframework.web.servlet.resource.AppCacheManifestTransformer;
import org.springframework.web.servlet.resource.EncodedResourceResolver;
import org.springframework.web.servlet.resource.ResourceHttpRequestHandler;
import org.springframework.web.servlet.resource.ResourceResolver;
import org.springframework.web.servlet.resource.VersionResourceResolver;
import org.springframework.web.servlet.view.BeanNameViewResolver;
import org.springframework.web.servlet.view.ContentNegotiatingViewResolver;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
/**
* {@link EnableAutoConfiguration Auto-configuration} for {@link EnableWebMvc Web MVC}.
*
* @author Phillip Webb
* @author Dave Syer
* @author Andy Wilkinson
* @author Sébastien Deleuze
* @author Eddú Meléndez
* @author Stephane Nicoll
* @author Kristine Jetzke
* @author Bruce Brouwer
* @author Artsiom Yudovin
*/
@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 {
public static final String DEFAULT_PREFIX = "";
public static final String DEFAULT_SUFFIX = "";
private static final String[] SERVLET_LOCATIONS = { "/" };
@Bean
@ConditionalOnMissingBean(HiddenHttpMethodFilter.class)
@ConditionalOnProperty(prefix = "spring.mvc.hiddenmethod.filter", name = "enabled", matchIfMissing = true)
public OrderedHiddenHttpMethodFilter hiddenHttpMethodFilter() {
return new OrderedHiddenHttpMethodFilter();
}
@Bean
@ConditionalOnMissingBean(FormContentFilter.class)
@ConditionalOnProperty(prefix = "spring.mvc.formcontent.filter", name = "enabled", matchIfMissing = true)
public OrderedFormContentFilter formContentFilter() {
return new OrderedFormContentFilter();
}
// Defined as a nested config to ensure WebMvcConfigurer is not read when not
// on the classpath
@Configuration
@Import(EnableWebMvcConfiguration.class)
@EnableConfigurationProperties({ WebMvcProperties.class, ResourceProperties.class })
@Order(0)
public static class WebMvcAutoConfigurationAdapter implements WebMvcConfigurer, ResourceLoaderAware {
private static final Log logger = LogFactory.getLog(WebMvcConfigurer.class);
private final ResourceProperties resourceProperties;
private final WebMvcProperties mvcProperties;
private final ListableBeanFactory beanFactory;
private final ObjectProvider messageConvertersProvider;
final ResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCustomizer;
private ResourceLoader resourceLoader;
public WebMvcAutoConfigurationAdapter(ResourceProperties resourceProperties, WebMvcProperties mvcProperties,
ListableBeanFactory beanFactory, ObjectProvider messageConvertersProvider,
ObjectProvider resourceHandlerRegistrationCustomizerProvider) {
this.resourceProperties = resourceProperties;
this.mvcProperties = mvcProperties;
this.beanFactory = beanFactory;
this.messageConvertersProvider = messageConvertersProvider;
this.resourceHandlerRegistrationCustomizer = resourceHandlerRegistrationCustomizerProvider.getIfAvailable();
}
@Override
public void setResourceLoader(ResourceLoader resourceLoader) {
this.resourceLoader = resourceLoader;
}
@Override
public void configureMessageConverters(List> converters) {
this.messageConvertersProvider
.ifAvailable((customConverters) -> converters.addAll(customConverters.getConverters()));
}
@Override
public void configureAsyncSupport(AsyncSupportConfigurer configurer) {
if (this.beanFactory.containsBean(TaskExecutionAutoConfiguration.APPLICATION_TASK_EXECUTOR_BEAN_NAME)) {
Object taskExecutor = this.beanFactory
.getBean(TaskExecutionAutoConfiguration.APPLICATION_TASK_EXECUTOR_BEAN_NAME);
if (taskExecutor instanceof AsyncTaskExecutor) {
configurer.setTaskExecutor(((AsyncTaskExecutor) taskExecutor));
}
}
Duration timeout = this.mvcProperties.getAsync().getRequestTimeout();
if (timeout != null) {
configurer.setDefaultTimeout(timeout.toMillis());
}
}
@Override
public void configurePathMatch(PathMatchConfigurer configurer) {
configurer.setUseSuffixPatternMatch(this.mvcProperties.getPathmatch().isUseSuffixPattern());
configurer.setUseRegisteredSuffixPatternMatch(
this.mvcProperties.getPathmatch().isUseRegisteredSuffixPattern());
}
@Override
public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
WebMvcProperties.Contentnegotiation contentnegotiation = this.mvcProperties.getContentnegotiation();
configurer.favorPathExtension(contentnegotiation.isFavorPathExtension());
configurer.favorParameter(contentnegotiation.isFavorParameter());
if (contentnegotiation.getParameterName() != null) {
configurer.parameterName(contentnegotiation.getParameterName());
}
Map mediaTypes = this.mvcProperties.getContentnegotiation().getMediaTypes();
mediaTypes.forEach(configurer::mediaType);
}
@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));
// ContentNegotiatingViewResolver uses all the other view resolvers to locate
// a view so it should have a high precedence
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;
}
@Override
public MessageCodesResolver getMessageCodesResolver() {
if (this.mvcProperties.getMessageCodesResolverFormat() != null) {
DefaultMessageCodesResolver resolver = new DefaultMessageCodesResolver();
resolver.setMessageCodeFormatter(this.mvcProperties.getMessageCodesResolverFormat());
return resolver;
}
return null;
}
@Override
public void addFormatters(FormatterRegistry registry) {
for (Converter converter : getBeansOfType(Converter.class)) {
registry.addConverter(converter);
}
for (GenericConverter converter : getBeansOfType(GenericConverter.class)) {
registry.addConverter(converter);
}
for (Formatter formatter : getBeansOfType(Formatter.class)) {
registry.addFormatter(formatter);
}
}
private Collection getBeansOfType(Class type) {
return this.beanFactory.getBeansOfType(type).values();
}
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
if (!this.resourceProperties.isAddMappings()) {
logger.debug("Default resource handling disabled");
return;
}
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));
}
}
private Integer getSeconds(Duration cachePeriod) {
return (cachePeriod != null) ? (int) cachePeriod.getSeconds() : null;
}
@Bean
public WelcomePageHandlerMapping welcomePageHandlerMapping(ApplicationContext applicationContext) {
return new WelcomePageHandlerMapping(new TemplateAvailabilityProviders(applicationContext),
applicationContext, getWelcomePage(), this.mvcProperties.getStaticPathPattern());
}
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 Optional getWelcomePage() {
String[] locations = getResourceLocations(this.resourceProperties.getStaticLocations());
return Arrays.stream(locations).map(this::getIndexHtml).filter(this::isReadable).findFirst();
}
private Resource getIndexHtml(String location) {
return this.resourceLoader.getResource(location + "index.html");
}
private boolean isReadable(Resource resource) {
try {
return resource.exists() && (resource.getURL() != null);
}
catch (Exception ex) {
return false;
}
}
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();
}
@Configuration
@ConditionalOnProperty(value = "spring.mvc.favicon.enabled", matchIfMissing = true)
public static class FaviconConfiguration implements ResourceLoaderAware {
private final ResourceProperties resourceProperties;
private ResourceLoader resourceLoader;
public FaviconConfiguration(ResourceProperties resourceProperties) {
this.resourceProperties = resourceProperties;
}
@Override
public void setResourceLoader(ResourceLoader resourceLoader) {
this.resourceLoader = resourceLoader;
}
@Bean
public SimpleUrlHandlerMapping faviconHandlerMapping() {
SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping();
mapping.setOrder(Ordered.HIGHEST_PRECEDENCE + 1);
mapping.setUrlMap(Collections.singletonMap("**/favicon.ico", faviconRequestHandler()));
return mapping;
}
@Bean
public ResourceHttpRequestHandler faviconRequestHandler() {
ResourceHttpRequestHandler requestHandler = new ResourceHttpRequestHandler();
requestHandler.setLocations(resolveFaviconLocations());
return requestHandler;
}
private List resolveFaviconLocations() {
String[] staticLocations = getResourceLocations(this.resourceProperties.getStaticLocations());
List locations = new ArrayList<>(staticLocations.length + 1);
Arrays.stream(staticLocations).map(this.resourceLoader::getResource).forEach(locations::add);
locations.add(new ClassPathResource("/"));
return Collections.unmodifiableList(locations);
}
}
}
/**
* Configuration equivalent to {@code @EnableWebMvc}.
*/
@Configuration
public static class EnableWebMvcConfiguration extends DelegatingWebMvcConfiguration {
private final WebMvcProperties mvcProperties;
private final ListableBeanFactory beanFactory;
private final WebMvcRegistrations mvcRegistrations;
public EnableWebMvcConfiguration(ObjectProvider mvcPropertiesProvider,
ObjectProvider 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();
}
@Bean
@Override
public FormattingConversionService mvcConversionService() {
WebConversionService conversionService = new WebConversionService(this.mvcProperties.getDateFormat());
addFormatters(conversionService);
return conversionService;
}
@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();
}
return super.createRequestMappingHandlerMapping();
}
@Override
protected ConfigurableWebBindingInitializer getConfigurableWebBindingInitializer() {
try {
return this.beanFactory.getBean(ConfigurableWebBindingInitializer.class);
}
catch (NoSuchBeanDefinitionException ex) {
return super.getConfigurableWebBindingInitializer();
}
}
@Override
protected ExceptionHandlerExceptionResolver createExceptionHandlerExceptionResolver() {
if (this.mvcRegistrations != null && this.mvcRegistrations.getExceptionHandlerExceptionResolver() != null) {
return this.mvcRegistrations.getExceptionHandlerExceptionResolver();
}
return super.createExceptionHandlerExceptionResolver();
}
@Override
protected void configureHandlerExceptionResolvers(List 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 strategies = manager.getStrategies();
ListIterator iterator = strategies.listIterator();
while (iterator.hasNext()) {
ContentNegotiationStrategy strategy = iterator.next();
if (strategy instanceof PathExtensionContentNegotiationStrategy) {
iterator.set(new OptionalPathExtensionContentNegotiationStrategy(strategy));
}
}
return manager;
}
}
@Configuration
@ConditionalOnEnabledResourceChain
static class ResourceChainCustomizerConfiguration {
@Bean
public ResourceChainResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCustomizer() {
return new ResourceChainResourceHandlerRegistrationCustomizer();
}
}
interface ResourceHandlerRegistrationCustomizer {
void customize(ResourceHandlerRegistration registration);
}
static class ResourceChainResourceHandlerRegistrationCustomizer implements ResourceHandlerRegistrationCustomizer {
@Autowired
private ResourceProperties resourceProperties = new ResourceProperties();
@Override
public void customize(ResourceHandlerRegistration registration) {
ResourceProperties.Chain properties = this.resourceProperties.getChain();
configureResourceChain(properties, registration.resourceChain(properties.isCache()));
}
private void configureResourceChain(ResourceProperties.Chain properties, ResourceChainRegistration chain) {
Strategy strategy = properties.getStrategy();
if (properties.isCompressed()) {
chain.addResolver(new EncodedResourceResolver());
}
if (strategy.getFixed().isEnabled() || strategy.getContent().isEnabled()) {
chain.addResolver(getVersionResourceResolver(strategy));
}
if (properties.isHtmlApplicationCache()) {
chain.addTransformer(new AppCacheManifestTransformer());
}
}
private ResourceResolver getVersionResourceResolver(ResourceProperties.Strategy properties) {
VersionResourceResolver resolver = new VersionResourceResolver();
if (properties.getFixed().isEnabled()) {
String version = properties.getFixed().getVersion();
String[] paths = properties.getFixed().getPaths();
resolver.addFixedVersionStrategy(version, paths);
}
if (properties.getContent().isEnabled()) {
String[] paths = properties.getContent().getPaths();
resolver.addContentVersionStrategy(paths);
}
return resolver;
}
}
/**
* Decorator to make {@link PathExtensionContentNegotiationStrategy} optional
* depending on a request attribute.
*/
static class OptionalPathExtensionContentNegotiationStrategy implements ContentNegotiationStrategy {
private static final String SKIP_ATTRIBUTE = PathExtensionContentNegotiationStrategy.class.getName() + ".SKIP";
private final ContentNegotiationStrategy delegate;
OptionalPathExtensionContentNegotiationStrategy(ContentNegotiationStrategy delegate) {
this.delegate = delegate;
}
@Override
public List resolveMediaTypes(NativeWebRequest webRequest)
throws HttpMediaTypeNotAcceptableException {
Object skip = webRequest.getAttribute(SKIP_ATTRIBUTE, RequestAttributes.SCOPE_REQUEST);
if (skip != null && Boolean.parseBoolean(skip.toString())) {
return MEDIA_TYPE_ALL_LIST;
}
return this.delegate.resolveMediaTypes(webRequest);
}
}
}
DispatcherServletAutoConfiguration 这个类将通过 DispatcherServletRegistrationBean 注册一个ServletContextInitializer到Servlet 容器中 ，具体描述如下：
A ServletContextInitializer to register Servlets in a Servlet 3.0+ container. Similar to the registration features provided by ServletContext but with a Spring Bean friendly design.
The servlet must be specified before calling onStartup. URL mapping can be configured used setUrlMappings or omitted when mapping to '/*' (unless alwaysMapUrl is set to false). The servlet name will be deduced if not specified.
servlet 容器将基于 ServletContextInitializer#onStartup()方法进行动态servlet初始化，该方法将DispatchServlet进行容器启动的初始化，作为servlet ， DispatchServlet 将实现所有servlet接口的方法。
ok， 我们看下代码：
@Override
public final void init() throws ServletException {
// Set bean properties from init parameters.
PropertyValues pvs = new ServletConfigPropertyValues(getServletConfig(), this.requiredProperties);
if (!pvs.isEmpty()) {
try {
BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(this);
ResourceLoader resourceLoader = new ServletContextResourceLoader(getServletContext());
bw.registerCustomEditor(Resource.class, new ResourceEditor(resourceLoader, getEnvironment()));
initBeanWrapper(bw);
bw.setPropertyValues(pvs, true);
}
catch (BeansException ex) {
if (logger.isErrorEnabled()) {
logger.error("Failed to set bean properties on servlet '" + getServletName() + "'", ex);
}
throw ex;
}
}
// Let subclasses do whatever initialization they like.
initServletBean();
}
该初始化方法是final修饰的，子类将实现initServletBean（）这个方法才能完成 初始化动作 ， 我们层层查找， 最总发现，DispatchServlet的初始化动作是在 这里：
/**
* This implementation calls {@link #initStrategies}.
*/
@Override
protected void onRefresh(ApplicationContext context) {
initStrategies(context);
}
/**
* Initialize the strategy objects that this servlet uses.
* May be overridden in subclasses in order to initialize further strategy objects.
*/
protected void initStrategies(ApplicationContext context) {
initMultipartResolver(context);
initLocaleResolver(context);
initThemeResolver(context);
initHandlerMappings(context);
initHandlerAdapters(context);
initHandlerExceptionResolvers(context);
initRequestToViewNameTranslator(context);
initViewResolvers(context);
initFlashMapManager(context);
}
到这里为止 ， 我们找到了第一个问题的答案， 我们知道了DispatchServlet的初始化的流程；那么对于controller中 方法与url的映射是怎么做到的呢 ，@RequestMapping 和@Controller是怎么何时解析的 呢 ，下节分析。