springboot的Web开发-Web相关配置

一：Spring Boot提供自动配置

       通过查看WebMvcAutoConfiguration及WebMvcProperties的源码，可以发现Spring Boot为我们提供了如下的自动配置。

 1，自动配置的ViewResolver

1）ContentNegotiatingViewResolver

    这是Spring MVC提供的一个特殊的ViewResolver，ContentNegotiatingViewResolver不是自己处理View，而是代理给不同的ViewResolver来处理不同的View，所以它有最高的优先级。

2）BeanNameViewResolver

    在控制器（@Controller）中的一个方法的返回值的字符串（视图名）会根据 BeanNameViewResolver去查找Bean的名称为返回字符串的View来渲染视图，下面举个例子

     定义BeanNameViewResolver的Bean

@Bean
    public BeanNameViewResolver beanNameViewResolver(){
        BeanNameViewResolver resolver= new BeanNameViewResolver();
        return resolver
    }

   定义一个View的Bean，名称为jsonView

@Bean
    public MappingJackson2JsonView jsonView(){
        MappingJackson2JsonView jsonView = new MappingJackson2JsonView();
        return jsonView;
    }

     在控制器中，返回值为字符串jsonView，它会找Bean的名称为jsonView的视图来渲染：

@RequestMapping(value = "json",produces = {MediaType.APPLICATION_JSON_VALUE})
    public String json(Model model){
        Person single = new Person("aa",11);
        model.addAttribute("single",single);
        return "jsonView";
    }

3)InternalResourceViewResolver

    这是一个常用的ViewResolver，主要通过设置前缀，后缀，以及控制器中方法来返回视图名的字符串，以得到实际页面，Spring Boot的源码如下：

@Bean
        @ConditionalOnMissingBean
        public InternalResourceViewResolver defaultViewResolver() {
            InternalResourceViewResolver resolver = new InternalResourceViewResolver();
            resolver.setPrefix(this.mvcProperties.getView().getPrefix());
            resolver.setSuffix(this.mvcProperties.getView().getSuffix());
            return resolver;
        }

下面是WebMvcAutoConfiguration的源代码：

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.boot.autoconfigure.web;

import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;
import java.util.Map.Entry;
import javax.servlet.Servlet;
import javax.servlet.http.HttpServletRequest;
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.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.validation.ValidationAutoConfiguration;
import org.springframework.boot.autoconfigure.web.ResourceProperties.Chain;
import org.springframework.boot.autoconfigure.web.ResourceProperties.Strategy;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.web.filter.OrderedHiddenHttpMethodFilter;
import org.springframework.boot.web.filter.OrderedHttpPutFormContentFilter;
import org.springframework.boot.web.filter.OrderedRequestContextFilter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.Lazy;
import org.springframework.context.annotation.Primary;
import org.springframework.core.convert.converter.Converter;
import org.springframework.core.convert.converter.GenericConverter;
import org.springframework.core.io.Resource;
import org.springframework.format.Formatter;
import org.springframework.format.FormatterRegistry;
import org.springframework.format.datetime.DateFormatter;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
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.RequestContextListener;
import org.springframework.web.filter.HiddenHttpMethodFilter;
import org.springframework.web.filter.HttpPutFormContentFilter;
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.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.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver;
import org.springframework.web.servlet.handler.AbstractUrlHandlerMapping;
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.ParameterizableViewController;
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.GzipResourceResolver;
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;

@Configuration
@ConditionalOnWebApplication
@ConditionalOnClass({Servlet.class, DispatcherServlet.class, WebMvcConfigurerAdapter.class})
@ConditionalOnMissingBean({WebMvcConfigurationSupport.class})
@AutoConfigureOrder(-2147483638)
@AutoConfigureAfter({DispatcherServletAutoConfiguration.class, ValidationAutoConfiguration.class})
public class WebMvcAutoConfiguration {
    public static final String DEFAULT_PREFIX = "";
    public static final String DEFAULT_SUFFIX = "";

    public WebMvcAutoConfiguration() {
    }

    @Bean
    @ConditionalOnMissingBean({HiddenHttpMethodFilter.class})
    public OrderedHiddenHttpMethodFilter hiddenHttpMethodFilter() {
        return new OrderedHiddenHttpMethodFilter();
    }

    @Bean
    @ConditionalOnMissingBean({HttpPutFormContentFilter.class})
    @ConditionalOnProperty(
        prefix = "spring.mvc.formcontent.putfilter",
        name = {"enabled"},
        matchIfMissing = true
    )
    public OrderedHttpPutFormContentFilter httpPutFormContentFilter() {
        return new OrderedHttpPutFormContentFilter();
    }

    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;
        }

        public List<MediaType> resolveMediaTypes(NativeWebRequest webRequest) throws HttpMediaTypeNotAcceptableException {
            Object skip = webRequest.getAttribute(SKIP_ATTRIBUTE, 0);
            return skip != null && Boolean.parseBoolean(skip.toString()) ? Collections.emptyList() : this.delegate.resolveMediaTypes(webRequest);
        }
    }

    static final class WelcomePageHandlerMapping extends AbstractUrlHandlerMapping {
        private static final Log logger = LogFactory.getLog(WebMvcAutoConfiguration.WelcomePageHandlerMapping.class);

        private WelcomePageHandlerMapping(Resource welcomePage, String staticPathPattern) {
            if (welcomePage != null && "/**".equals(staticPathPattern)) {
                logger.info("Adding welcome page: " + welcomePage);
                ParameterizableViewController controller = new ParameterizableViewController();
                controller.setViewName("forward:index.html");
                this.setRootHandler(controller);
                this.setOrder(0);
            }

        }

        public Object getHandlerInternal(HttpServletRequest request) throws Exception {
            Iterator var2 = this.getAcceptedMediaTypes(request).iterator();

            MediaType mediaType;
            do {
                if (!var2.hasNext()) {
                    return null;
                }

                mediaType = (MediaType)var2.next();
            } while(!mediaType.includes(MediaType.TEXT_HTML));

            return super.getHandlerInternal(request);
        }

        private List<MediaType> getAcceptedMediaTypes(HttpServletRequest request) {
            String acceptHeader = request.getHeader("Accept");
            return MediaType.parseMediaTypes(StringUtils.hasText(acceptHeader) ? acceptHeader : "*/*");
        }
    }

    private static class ResourceChainResourceHandlerRegistrationCustomizer implements WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer {
        @Autowired
        private ResourceProperties resourceProperties;

        private ResourceChainResourceHandlerRegistrationCustomizer() {
            this.resourceProperties = new ResourceProperties();
        }

        public void customize(ResourceHandlerRegistration registration) {
            Chain properties = this.resourceProperties.getChain();
            this.configureResourceChain(properties, registration.resourceChain(properties.isCache()));
        }

        private void configureResourceChain(Chain properties, ResourceChainRegistration chain) {
            Strategy strategy = properties.getStrategy();
            if (strategy.getFixed().isEnabled() || strategy.getContent().isEnabled()) {
                chain.addResolver(this.getVersionResourceResolver(strategy));
            }

            if (properties.isGzipped()) {
                chain.addResolver(new GzipResourceResolver());
            }

            if (properties.isHtmlApplicationCache()) {
                chain.addTransformer(new AppCacheManifestTransformer());
            }

        }

        private ResourceResolver getVersionResourceResolver(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;
        }
    }

    interface ResourceHandlerRegistrationCustomizer {
        void customize(ResourceHandlerRegistration var1);
    }

    @Configuration
    @ConditionalOnEnabledResourceChain
    static class ResourceChainCustomizerConfiguration {
        ResourceChainCustomizerConfiguration() {
        }

        @Bean
        public WebMvcAutoConfiguration.ResourceChainResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCustomizer() {
            return new WebMvcAutoConfiguration.ResourceChainResourceHandlerRegistrationCustomizer();
        }
    }

    @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 = (WebMvcProperties)mvcPropertiesProvider.getIfAvailable();
            this.mvcRegistrations = (WebMvcRegistrations)mvcRegistrationsProvider.getIfUnique();
            this.beanFactory = beanFactory;
        }

        @Bean
        public RequestMappingHandlerAdapter requestMappingHandlerAdapter() {
            RequestMappingHandlerAdapter adapter = super.requestMappingHandlerAdapter();
            adapter.setIgnoreDefaultModelOnRedirect(this.mvcProperties == null ? true : this.mvcProperties.isIgnoreDefaultModelOnRedirect());
            return adapter;
        }

        protected RequestMappingHandlerAdapter createRequestMappingHandlerAdapter() {
            return this.mvcRegistrations != null && this.mvcRegistrations.getRequestMappingHandlerAdapter() != null ? this.mvcRegistrations.getRequestMappingHandlerAdapter() : super.createRequestMappingHandlerAdapter();
        }

        @Bean
        @Primary
        public RequestMappingHandlerMapping requestMappingHandlerMapping() {
            return super.requestMappingHandlerMapping();
        }

        @Bean
        public Validator mvcValidator() {
            return !ClassUtils.isPresent("javax.validation.Validator", this.getClass().getClassLoader()) ? super.mvcValidator() : WebMvcValidator.get(this.getApplicationContext(), this.getValidator());
        }

        protected RequestMappingHandlerMapping createRequestMappingHandlerMapping() {
            return this.mvcRegistrations != null && this.mvcRegistrations.getRequestMappingHandlerMapping() != null ? this.mvcRegistrations.getRequestMappingHandlerMapping() : super.createRequestMappingHandlerMapping();
        }

        protected ConfigurableWebBindingInitializer getConfigurableWebBindingInitializer() {
            try {
                return (ConfigurableWebBindingInitializer)this.beanFactory.getBean(ConfigurableWebBindingInitializer.class);
            } catch (NoSuchBeanDefinitionException var2) {
                return super.getConfigurableWebBindingInitializer();
            }
        }

        protected ExceptionHandlerExceptionResolver createExceptionHandlerExceptionResolver() {
            return this.mvcRegistrations != null && this.mvcRegistrations.getExceptionHandlerExceptionResolver() != null ? this.mvcRegistrations.getExceptionHandlerExceptionResolver() : super.createExceptionHandlerExceptionResolver();
        }

        protected void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {
            super.configureHandlerExceptionResolvers(exceptionResolvers);
            if (exceptionResolvers.isEmpty()) {
                this.addDefaultHandlerExceptionResolvers(exceptionResolvers);
            }

            if (this.mvcProperties.isLogResolvedException()) {
                Iterator var2 = exceptionResolvers.iterator();

                while(var2.hasNext()) {
                    HandlerExceptionResolver resolver = (HandlerExceptionResolver)var2.next();
                    if (resolver instanceof AbstractHandlerExceptionResolver) {
                        ((AbstractHandlerExceptionResolver)resolver).setWarnLogCategory(resolver.getClass().getName());
                    }
                }
            }

        }

        @Bean
        public ContentNegotiationManager mvcContentNegotiationManager() {
            ContentNegotiationManager manager = super.mvcContentNegotiationManager();
            List<ContentNegotiationStrategy> strategies = manager.getStrategies();
            ListIterator iterator = strategies.listIterator();

            while(iterator.hasNext()) {
                ContentNegotiationStrategy strategy = (ContentNegotiationStrategy)iterator.next();
                if (strategy instanceof PathExtensionContentNegotiationStrategy) {
                    iterator.set(new WebMvcAutoConfiguration.OptionalPathExtensionContentNegotiationStrategy(strategy));
                }
            }

            return manager;
        }
    }

    @Configuration
    @Import({WebMvcAutoConfiguration.EnableWebMvcConfiguration.class})
    @EnableConfigurationProperties({WebMvcProperties.class, ResourceProperties.class})
    public static class WebMvcAutoConfigurationAdapter extends WebMvcConfigurerAdapter {
        private static final Log logger = LogFactory.getLog(WebMvcConfigurerAdapter.class);
        private final ResourceProperties resourceProperties;
        private final WebMvcProperties mvcProperties;
        private final ListableBeanFactory beanFactory;
        private final HttpMessageConverters messageConverters;
        final WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCustomizer;

        public WebMvcAutoConfigurationAdapter(ResourceProperties resourceProperties, WebMvcProperties mvcProperties, ListableBeanFactory beanFactory, @Lazy HttpMessageConverters messageConverters, ObjectProvider<WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer> resourceHandlerRegistrationCustomizerProvider) {
            this.resourceProperties = resourceProperties;
            this.mvcProperties = mvcProperties;
            this.beanFactory = beanFactory;
            this.messageConverters = messageConverters;
            this.resourceHandlerRegistrationCustomizer = (WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer)resourceHandlerRegistrationCustomizerProvider.getIfAvailable();
        }

        public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
            converters.addAll(this.messageConverters.getConverters());
        }

        public void configureAsyncSupport(AsyncSupportConfigurer configurer) {
            Long timeout = this.mvcProperties.getAsync().getRequestTimeout();
            if (timeout != null) {
                configurer.setDefaultTimeout(timeout.longValue());
            }

        }

        public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
            Map<String, MediaType> mediaTypes = this.mvcProperties.getMediaTypes();
            Iterator var3 = mediaTypes.entrySet().iterator();

            while(var3.hasNext()) {
                Entry<String, MediaType> mediaType = (Entry)var3.next();
                configurer.mediaType((String)mediaType.getKey(), (MediaType)mediaType.getValue());
            }

        }

        @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(2147483637);
            return resolver;
        }

        @Bean
        @ConditionalOnBean({ViewResolver.class})
        @ConditionalOnMissingBean(
            name = {"viewResolver"},
            value = {ContentNegotiatingViewResolver.class}
        )
        public ContentNegotiatingViewResolver viewResolver(BeanFactory beanFactory) {
            ContentNegotiatingViewResolver resolver = new ContentNegotiatingViewResolver();
            resolver.setContentNegotiationManager((ContentNegotiationManager)beanFactory.getBean(ContentNegotiationManager.class));
            resolver.setOrder(-2147483648);
            return resolver;
        }

        @Bean
        @ConditionalOnMissingBean
        @ConditionalOnProperty(
            prefix = "spring.mvc",
            name = {"locale"}
        )
        public LocaleResolver localeResolver() {
            if (this.mvcProperties.getLocaleResolver() == org.springframework.boot.autoconfigure.web.WebMvcProperties.LocaleResolver.FIXED) {
                return new FixedLocaleResolver(this.mvcProperties.getLocale());
            } else {
                AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver();
                localeResolver.setDefaultLocale(this.mvcProperties.getLocale());
                return localeResolver;
            }
        }

        @Bean
        @ConditionalOnProperty(
            prefix = "spring.mvc",
            name = {"date-format"}
        )
        public Formatter<Date> dateFormatter() {
            return new DateFormatter(this.mvcProperties.getDateFormat());
        }

        public MessageCodesResolver getMessageCodesResolver() {
            if (this.mvcProperties.getMessageCodesResolverFormat() != null) {
                DefaultMessageCodesResolver resolver = new DefaultMessageCodesResolver();
                resolver.setMessageCodeFormatter(this.mvcProperties.getMessageCodesResolverFormat());
                return resolver;
            } else {
                return null;
            }
        }

        public void addFormatters(FormatterRegistry registry) {
            Iterator var2 = this.getBeansOfType(Converter.class).iterator();

            while(var2.hasNext()) {
                Converter<?, ?> converter = (Converter)var2.next();
                registry.addConverter(converter);
            }

            var2 = this.getBeansOfType(GenericConverter.class).iterator();

            while(var2.hasNext()) {
                GenericConverter converter = (GenericConverter)var2.next();
                registry.addConverter(converter);
            }

            var2 = this.getBeansOfType(Formatter.class).iterator();

            while(var2.hasNext()) {
                Formatter<?> formatter = (Formatter)var2.next();
                registry.addFormatter(formatter);
            }

        }

        private <T> Collection<T> getBeansOfType(Class<T> type) {
            return this.beanFactory.getBeansOfType(type).values();
        }

        public void addResourceHandlers(ResourceHandlerRegistry registry) {
            if (!this.resourceProperties.isAddMappings()) {
                logger.debug("Default resource handling disabled");
            } else {
                Integer cachePeriod = this.resourceProperties.getCachePeriod();
                if (!registry.hasMappingForPattern("/webjars/**")) {
                    this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{"/webjars/**"}).addResourceLocations(new String[]{"classpath:/META-INF/resources/webjars/"}).setCachePeriod(cachePeriod));
                }

                String staticPathPattern = this.mvcProperties.getStaticPathPattern();
                if (!registry.hasMappingForPattern(staticPathPattern)) {
                    this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{staticPathPattern}).addResourceLocations(this.resourceProperties.getStaticLocations()).setCachePeriod(cachePeriod));
                }

            }
        }

        @Bean
        public WebMvcAutoConfiguration.WelcomePageHandlerMapping welcomePageHandlerMapping(ResourceProperties resourceProperties) {
            return new WebMvcAutoConfiguration.WelcomePageHandlerMapping(resourceProperties.getWelcomePage(), this.mvcProperties.getStaticPathPattern());
        }

        private void customizeResourceHandlerRegistration(ResourceHandlerRegistration registration) {
            if (this.resourceHandlerRegistrationCustomizer != null) {
                this.resourceHandlerRegistrationCustomizer.customize(registration);
            }

        }

        @Bean
        @ConditionalOnMissingBean({RequestContextListener.class, RequestContextFilter.class})
        public static RequestContextFilter requestContextFilter() {
            return new OrderedRequestContextFilter();
        }

        @Configuration
        @ConditionalOnProperty(
            value = {"spring.mvc.favicon.enabled"},
            matchIfMissing = true
        )
        public static class FaviconConfiguration {
            private final ResourceProperties resourceProperties;

            public FaviconConfiguration(ResourceProperties resourceProperties) {
                this.resourceProperties = resourceProperties;
            }

            @Bean
            public SimpleUrlHandlerMapping faviconHandlerMapping() {
                SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping();
                mapping.setOrder(-2147483647);
                mapping.setUrlMap(Collections.singletonMap("**/favicon.ico", this.faviconRequestHandler()));
                return mapping;
            }

            @Bean
            public ResourceHttpRequestHandler faviconRequestHandler() {
                ResourceHttpRequestHandler requestHandler = new ResourceHttpRequestHandler();
                requestHandler.setLocations(this.resourceProperties.getFaviconLocations());
                return requestHandler;
            }
        }
    }
}

WebMvcProperties的源码如下：

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.boot.autoconfigure.web;

import java.util.LinkedHashMap;
import java.util.Locale;
import java.util.Map;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.http.MediaType;
import org.springframework.validation.DefaultMessageCodesResolver.Format;

@ConfigurationProperties(
    prefix = "spring.mvc"
)
public class WebMvcProperties {
    private Format messageCodesResolverFormat;
    private Locale locale;
    private WebMvcProperties.LocaleResolver localeResolver;
    private String dateFormat;
    private boolean dispatchTraceRequest;
    private boolean dispatchOptionsRequest;
    private boolean ignoreDefaultModelOnRedirect;
    private boolean throwExceptionIfNoHandlerFound;
    private boolean logResolvedException;
    private Map<String, MediaType> mediaTypes;
    private String staticPathPattern;
    private final WebMvcProperties.Async async;
    private final WebMvcProperties.Servlet servlet;
    private final WebMvcProperties.View view;

    public WebMvcProperties() {
        this.localeResolver = WebMvcProperties.LocaleResolver.ACCEPT_HEADER;
        this.dispatchTraceRequest = false;
        this.dispatchOptionsRequest = true;
        this.ignoreDefaultModelOnRedirect = true;
        this.throwExceptionIfNoHandlerFound = false;
        this.logResolvedException = false;
        this.mediaTypes = new LinkedHashMap();
        this.staticPathPattern = "/**";
        this.async = new WebMvcProperties.Async();
        this.servlet = new WebMvcProperties.Servlet();
        this.view = new WebMvcProperties.View();
    }

    public Format getMessageCodesResolverFormat() {
        return this.messageCodesResolverFormat;
    }

    public void setMessageCodesResolverFormat(Format messageCodesResolverFormat) {
        this.messageCodesResolverFormat = messageCodesResolverFormat;
    }

    public Locale getLocale() {
        return this.locale;
    }

    public void setLocale(Locale locale) {
        this.locale = locale;
    }

    public WebMvcProperties.LocaleResolver getLocaleResolver() {
        return this.localeResolver;
    }

    public void setLocaleResolver(WebMvcProperties.LocaleResolver localeResolver) {
        this.localeResolver = localeResolver;
    }

    public String getDateFormat() {
        return this.dateFormat;
    }

    public void setDateFormat(String dateFormat) {
        this.dateFormat = dateFormat;
    }

    public boolean isIgnoreDefaultModelOnRedirect() {
        return this.ignoreDefaultModelOnRedirect;
    }

    public void setIgnoreDefaultModelOnRedirect(boolean ignoreDefaultModelOnRedirect) {
        this.ignoreDefaultModelOnRedirect = ignoreDefaultModelOnRedirect;
    }

    public boolean isThrowExceptionIfNoHandlerFound() {
        return this.throwExceptionIfNoHandlerFound;
    }

    public void setThrowExceptionIfNoHandlerFound(boolean throwExceptionIfNoHandlerFound) {
        this.throwExceptionIfNoHandlerFound = throwExceptionIfNoHandlerFound;
    }

    public boolean isLogResolvedException() {
        return this.logResolvedException;
    }

    public void setLogResolvedException(boolean logResolvedException) {
        this.logResolvedException = logResolvedException;
    }

    public Map<String, MediaType> getMediaTypes() {
        return this.mediaTypes;
    }

    public void setMediaTypes(Map<String, MediaType> mediaTypes) {
        this.mediaTypes = mediaTypes;
    }

    public boolean isDispatchOptionsRequest() {
        return this.dispatchOptionsRequest;
    }

    public void setDispatchOptionsRequest(boolean dispatchOptionsRequest) {
        this.dispatchOptionsRequest = dispatchOptionsRequest;
    }

    public boolean isDispatchTraceRequest() {
        return this.dispatchTraceRequest;
    }

    public void setDispatchTraceRequest(boolean dispatchTraceRequest) {
        this.dispatchTraceRequest = dispatchTraceRequest;
    }

    public String getStaticPathPattern() {
        return this.staticPathPattern;
    }

    public void setStaticPathPattern(String staticPathPattern) {
        this.staticPathPattern = staticPathPattern;
    }

    public WebMvcProperties.Async getAsync() {
        return this.async;
    }

    public WebMvcProperties.Servlet getServlet() {
        return this.servlet;
    }

    public WebMvcProperties.View getView() {
        return this.view;
    }

    public static enum LocaleResolver {
        FIXED,
        ACCEPT_HEADER;

        private LocaleResolver() {
        }
    }

    public static class View {
        private String prefix;
        private String suffix;

        public View() {
        }

        public String getPrefix() {
            return this.prefix;
        }

        public void setPrefix(String prefix) {
            this.prefix = prefix;
        }

        public String getSuffix() {
            return this.suffix;
        }

        public void setSuffix(String suffix) {
            this.suffix = suffix;
        }
    }

    public static class Servlet {
        private int loadOnStartup = -1;

        public Servlet() {
        }

        public int getLoadOnStartup() {
            return this.loadOnStartup;
        }

        public void setLoadOnStartup(int loadOnStartup) {
            this.loadOnStartup = loadOnStartup;
        }
    }

    public static class Async {
        private Long requestTimeout;

        public Async() {
        }

        public Long getRequestTimeout() {
            return this.requestTimeout;
        }

        public void setRequestTimeout(Long requestTimeout) {
            this.requestTimeout = requestTimeout;
        }
    }
}

2，自动配置的静态资源

    在自动配置类的addResourceHandlers方法中定义了以下静态资源的自动配置。

1）类路径文件

    把类路径下的/static,/public,/resources和/META-INF/resources文件夹下的静态文件直接映射为/**，可以通过http://localhost:8080/**来访问。

2）webjar

        何谓webjar，webjar就是将是我们常用的脚本框架封装在jar包中的jar包，更多关于webjar的内容请访问http://www.webjars.org网站

    把webjar的/META-INF/resources/webjars/下的静态文件映射为/webjar/**,可以通过http://localhost:8080/webjar/**来访问

     

3，自动配置的Formatter和Converter

     关于自动配置的Formatter和Converter，我们可以看一下WebMvcAutoConfiguration类中的定义：

public void addFormatters(FormatterRegistry registry) {
            Iterator var2 = this.getBeansOfType(Converter.class).iterator();

            while(var2.hasNext()) {
                Converter<?, ?> converter = (Converter)var2.next();
                registry.addConverter(converter);
            }

            var2 = this.getBeansOfType(GenericConverter.class).iterator();

            while(var2.hasNext()) {
                GenericConverter converter = (GenericConverter)var2.next();
                registry.addConverter(converter);
            }

            var2 = this.getBeansOfType(Formatter.class).iterator();

            while(var2.hasNext()) {
                Formatter<?> formatter = (Formatter)var2.next();
                registry.addFormatter(formatter);
            }

        }

      从代码中可以看出，只要我们定义了Converter，GenericConverter和Formatter接口的事项类的Bean，这些Bean就会自动注册到Spring MVC中。

4，自动配置的HttpMessageConverters

    在WebMvcAutoConfiguration中，我们注册了messageConverters，代码如下：

@Configuration
    @Import({WebMvcAutoConfiguration.EnableWebMvcConfiguration.class})
    @EnableConfigurationProperties({WebMvcProperties.class, ResourceProperties.class})
    public static class WebMvcAutoConfigurationAdapter extends WebMvcConfigurerAdapter {
        private static final Log logger = LogFactory.getLog(WebMvcConfigurerAdapter.class);
        private final ResourceProperties resourceProperties;
        private final WebMvcProperties mvcProperties;
        private final ListableBeanFactory beanFactory;
        private final HttpMessageConverters messageConverters;
        final WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCustomizer;

        public WebMvcAutoConfigurationAdapter(ResourceProperties resourceProperties, WebMvcProperties mvcProperties, ListableBeanFactory beanFactory, @Lazy HttpMessageConverters messageConverters, ObjectProvider<WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer> resourceHandlerRegistrationCustomizerProvider) {
            this.resourceProperties = resourceProperties;
            this.mvcProperties = mvcProperties;
            this.beanFactory = beanFactory;
            this.messageConverters = messageConverters;
            this.resourceHandlerRegistrationCustomizer = (WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer)resourceHandlerRegistrationCustomizerProvider.getIfAvailable();
        }

        public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
            converters.addAll(this.messageConverters.getConverters());
        }

        public void configureAsyncSupport(AsyncSupportConfigurer configurer) {
            Long timeout = this.mvcProperties.getAsync().getRequestTimeout();
            if (timeout != null) {
                configurer.setDefaultTimeout(timeout.longValue());
            }

        }

       在这里直接注入了HttpMessageConverters的Bean，而这个Bean是在HttpMessageConvertersAutoConfiguration类中定义的，我们自动扫描注册的HttpMessage Converter除了Spring MVC默认的ByteArrayHttpMessageConverter，StringHttpMessage Converter，Resource HttpMessageConverter等外，还自动配置文件里引入了JacksonHttpMessageConverters Configuration和GsonHttpMessage ConverterConfiguration，使我们获得了额外的HttpMessageConverter：

      若jackson的jar包在路径上，则Spring Boot通过JacksonHttpMessage Converters Configuration增加了MappingJackson2HttpMessage Converter和Mapping Jackson2XmlHttpMessageConverter

     若gson的jar包在路径上，则Spring Boot通过GsonHttpMessageConverterConfiguration增加GsonHttpMessageConverter

      在Spring Boot中如果要新增自定义的HttpMessageConverter，则只需定义一个你自己的HttpMessageConverters的Bean，然后在此Bean中注册自定义的HttpMessageConverter即可，如下：

@Bean
    public HttpMessageConverters customConverters(){
        HttpMessageConverter<?> customConverter1 = new CustomConverter1();
        HttpMessageConverter<?> customConverter2 = new CustomConverter2();
        return new HttpMessageConverters(customConverter1,customConverter2)
    }

5，静态首页的支持

把静态index.html文件放置在如下目录

classpath:/META-INF/resources/index.html

classpath:/resources/index.html

classpath:/static/index.html

classpath:/public/index.html

当我们访问应用根目录http://localhost:8080/时，会直接映射

二：接管Spring Boot的Web配置

        如果Spring Boot提供的Spring MVC默认配置不符合需求，则可以通过一个配置类（注解有@Configuration的类）加上@EnableWebMvc注解来实现完全自己控制的MVC配置。

       通常情况下，Spring Boot的自动配置是符合我们大多数需求的。在你既需要保留Spring Boot提供的便利，又需要增加自己额外的配置的时候，可以定义一个配置类并继承WebMvcConfigurerAdapter，无须使用@EnableWebMvc，例如：

package jack.springmvc.config;

import jack.springmvc.interceptor.DemoInterceptor;
import jack.springmvc.messageconverter.MyMessageConverter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.web.multipart.MultipartResolver;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;
import org.springframework.web.servlet.config.annotation.*;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;

import java.util.List;

/**
 * Created by jack on 2017/7/16.
 */
@Configuration
@EnableWebMvc   //开启Spring MVC支持，若无此句，重写WebMvcConfigurerAdapter方法无效
@ComponentScan("jack.springmvc")
@EnableScheduling   //开启计划任务的支持
//继承WebMvcConfigurerAdapter类，重写其方法可对Spring MVC进行配置
public class MyMvcConfig extends WebMvcConfigurerAdapter{

    /**
     * 配置拦截器的Bean
     * @return
     */
    @Bean
    public DemoInterceptor demoInterceptor(){
        return new DemoInterceptor();
    }

    /**
     * 配置文件上传Bean
     * @return
     */
    @Bean
    public MultipartResolver multipartResolver(){
        CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
        multipartResolver.setMaxUploadSize(1000000);
        return multipartResolver;
    }

    /**
     * c重写addInterceptors方法，注册拦截器
     * @param registry
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //super.addInterceptors(registry);
        registry.addInterceptor(demoInterceptor());
    }

    @Bean
    public InternalResourceViewResolver viewResolver(){
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        //viewResolver.setPrefix("/WEB-INF/classes/views/");
        viewResolver.setPrefix("/WEB-INF/classes/views/");
        viewResolver.setSuffix(".jsp");
        viewResolver.setViewClass(JstlView.class);
        return  viewResolver;
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        //super.addResourceHandlers(registry);
        //addResourceLocations指的是文件放置的目录，addResourceHandler指的是对外暴露的访问路径
        registry.addResourceHandler("/assets/**").addResourceLocations("classpath:/assets/");
    }

    /**
     * 统一处理没啥业务逻辑处理的controller请求，实现代码的简洁
     * @param registry
     */
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        //super.addViewControllers(registry);
        registry.addViewController("/index").setViewName("/index");
        registry.addViewController("/toUpload").setViewName("upload");
        registry.addViewController("/converter").setViewName("/converter");
        registry.addViewController("/sse").setViewName("/sse");
        registry.addViewController("/async").setViewName("/async");
    }

    @Override
    public void configurePathMatch(PathMatchConfigurer configurer) {
        //super.configurePathMatch(configurer);
        configurer.setUseSuffixPatternMatch(false);
    }

    /**
     * 配置自定义的HttpMessageConverter的bean，在spring mvc里注册HttpMessageConverter有两个方法：
     * configureMessageConverters：重载会覆盖掉Spring MVC默认注册的多个HttpMessageConverter
     * extendMessageConverters：仅添加一个自定义的HttpMessageConverter，不覆盖默认注册的HttpMessageConverter
     * @param converters
     */
    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
        //super.extendMessageConverters(converters);
        converters.add(converter());
    }

    @Bean
    public MyMessageConverter converter(){
        return new MyMessageConverter();
    }

}

     上注意，上面重写了了addViewController方法，并不会覆盖WebMvcAutoConfiguration中的addViewController（在此方法中Spring Boot将“/”映射至index.html），这也就意味着我们自己的配置和Spring Boot的自动配置同时有效，这也是推荐添加自己的MVC配置的方式。

三：接注册Servlet，Filter，Listener

      当使用嵌入式的Servlet容器时，我们通过将Servlet，Filter和Listener声明为Spring Bean而达到注册的效果；或者注册ServletRegistrationBean，FilterRegistrationBean和ServletListenerRegistrationBean的Bean。

1）直接注册Bean示例，代码如下：

@Bean
    public XxServlet xxServlet(){
        return new XxServlet();
    }

    @Bean
    public YyFilter yyFilter(){
        return new YyFilter();
    }

    @Bean
    public ZzListener zzListener(){
        return new ZzListener()
    }

2）通过RegistrationBean

@Bean
   public ServeletRegistrationBean serveletRegistrationBean(){
       return new ServeletRegistrationBean(new Xxservlet(),"/xx/*");
   }

   @Bean
   public FilterRegistrationBean filterRegistrationBean(){
       FilterRegistrationBean registrationBean = new FilterRegistrationBean();
       registrationBean.setFilter(new YyFilter());
       registrationBean.setOrder(2);
       return registrationBean;
   }
   @Bean
   public ServletListenerRegistrationBean<ZzListener> zzListenerServletListenerRegistrationBean(){
       return new ServletListenerRegistrationBean<ZzListener>(new ZzListener())