初入spring boot（四 ）web项目

1. 模板引擎

　　spring boot提供了大量的模板引擎，包括FreeMark、Groovy、Thymeleaf、Velocity等，但spring boot中推荐用Thymeleaf，因为Thymeleaf提供了完美的spring mvc的支持。

2. 与spring boot集成

　　在spring mvc中，若要集成一个模板引擎的话，需要定义ViewResolver，而ViewResolver需要定义一个View。Thymeleaf已经定义好了ViewResolver和View，分别是org.thymeleaf.spring4.view.ThymeleafViewResolver（默认使用ThymeleafView作为View）和org.thymeleaf.spring4.view.ThymeleafView。Thymeleaf提供了SpringTemplateEngine类，用来驱动在spring mvc下使用Thymeleaf模板引擎，另外还提供了一个TemplateResolver用来设置通用的模板引擎（包含前缀、后缀等），这使我们在spring mvc中集成Thymeleaf引擎变得十分简单。

　　上面说的是与spring mvc集成，但是ThymeleafView与Spring boot集成很方便，spring boot通过org.springframework.boot.autoconfigure.thymeleaf包对Thymeleaf进行了自动配置。

　　通过ThymeleafAutoConfiguration类对集成所需要的bean进行自动配置，包括templateResolver、templateEngine和thymeleafViewResolver的配置。

　　通过ThymeleafProperties来配置Thymeleaf，在application.properties中，以spring.thymeleaf开头来配置，通过查看ThymeleafProperties的主要源码，可以看出如何设置属性以及默认的配置：

 @ConfigurationProperties(prefix = "spring.thymeleaf")
 public class ThymeleafProperties {
 
     private static final Charset DEFAULT_ENCODING = Charset.forName("UTF-8");
 
     private static final MimeType DEFAULT_CONTENT_TYPE = MimeType.valueOf("text/html");
 
     public static final String DEFAULT_PREFIX = "classpath:/templates/";
 
     public static final String DEFAULT_SUFFIX = ".html";
 
     /**
      * Check that the template exists before rendering it (Thymeleaf 3+).
      */
     private boolean checkTemplate = true;
 
     /**
      * Check that the templates location exists.
      */
     private boolean checkTemplateLocation = true;
 
     /**
      * Prefix that gets prepended to view names when building a URL.
      */
     private String prefix = DEFAULT_PREFIX;
 
     /**
      * Suffix that gets appended to view names when building a URL.
      */
     private String suffix = DEFAULT_SUFFIX;
 
     /**
      * Template mode to be applied to templates. See also StandardTemplateModeHandlers.
      */
     private String mode = "HTML5";
 
     /**
      * Template encoding.
      */
     private Charset encoding = DEFAULT_ENCODING;
 
     /**
      * Content-Type value.
      */
     private MimeType contentType = DEFAULT_CONTENT_TYPE;
 
     /**
      * Enable template caching.
      */
     private boolean cache = true;
 
     /**
      * Order of the template resolver in the chain. By default, the template resolver is
      * first in the chain. Order start at 1 and should only be set if you have defined
      * additional "TemplateResolver" beans.
      */
     private Integer templateResolverOrder;
 
     /**
      * Comma-separated list of view names that can be resolved.
      */
     private String[] viewNames;
 
     /**
      * Comma-separated list of view names that should be excluded from resolution.
      */
     private String[] excludedViewNames;
 
     /**
      * Enable MVC Thymeleaf view resolution.
      */
     private boolean enabled = true;
 
     public boolean isEnabled() {
         return this.enabled;
     }
 
     public void setEnabled(boolean enabled) {
         this.enabled = enabled;
     }
 
     public boolean isCheckTemplate() {
         return this.checkTemplate;
     }
 
     public void setCheckTemplate(boolean checkTemplate) {
         this.checkTemplate = checkTemplate;
     }
 
     public boolean isCheckTemplateLocation() {
         return this.checkTemplateLocation;
     }
 
     public void setCheckTemplateLocation(boolean checkTemplateLocation) {
         this.checkTemplateLocation = checkTemplateLocation;
     }
 
     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 String getMode() {
         return this.mode;
     }
 
     public void setMode(String mode) {
         this.mode = mode;
     }
 
     public Charset getEncoding() {
         return this.encoding;
     }
 
     public void setEncoding(Charset encoding) {
         this.encoding = encoding;
     }
 
     public MimeType getContentType() {
         return this.contentType;
     }
 
     public void setContentType(MimeType contentType) {
         this.contentType = contentType;
     }
 
     public boolean isCache() {
         return this.cache;
     }
 
     public void setCache(boolean cache) {
         this.cache = cache;
     }
 
     public Integer getTemplateResolverOrder() {
         return this.templateResolverOrder;
     }
 
     public void setTemplateResolverOrder(Integer templateResolverOrder) {
         this.templateResolverOrder = templateResolverOrder;
     }
 
     public String[] getExcludedViewNames() {
         return this.excludedViewNames;
     }
 
     public void setExcludedViewNames(String[] excludedViewNames) {
         this.excludedViewNames = excludedViewNames;
     }
 
     public String[] getViewNames() {
         return this.viewNames;
     }
 
     public void setViewNames(String[] viewNames) {
         this.viewNames = viewNames;
     }
 
 }

3. web相关配置

　　3.1 spring boot提供的自动配置

　　通过查看WebMvcAutoConfiguration及WebMvcProperties的源码，可以发现spring boot提供了如下的自动配置

　　

 @Configuration
 @ConditionalOnWebApplication
 @ConditionalOnClass({ Servlet.class, DispatcherServlet.class,
         WebMvcConfigurerAdapter.class })
 @ConditionalOnMissingBean(WebMvcConfigurationSupport.class)
 @AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
 @AutoConfigureAfter({ DispatcherServletAutoConfiguration.class,
         ValidationAutoConfiguration.class })
 public class WebMvcAutoConfiguration {
 
     public static String DEFAULT_PREFIX = "";
 
     public static String DEFAULT_SUFFIX = "";
 
     @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();
     }
 
     // Defined as a nested config to ensure WebMvcConfigurerAdapter is not read when not
     // on the classpath
     @Configuration
     @Import(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 ResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCustomizer;
 
         public WebMvcAutoConfigurationAdapter(ResourceProperties resourceProperties,
                 WebMvcProperties mvcProperties, ListableBeanFactory beanFactory,
                 HttpMessageConverters messageConverters,
                 ObjectProvider<ResourceHandlerRegistrationCustomizer> resourceHandlerRegistrationCustomizerProvider) {
             this.resourceProperties = resourceProperties;
             this.mvcProperties = mvcProperties;
             this.beanFactory = beanFactory;
             this.messageConverters = messageConverters;
             this.resourceHandlerRegistrationCustomizer = resourceHandlerRegistrationCustomizerProvider
                     .getIfAvailable();
         }
 
         @Override
         public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
             converters.addAll(this.messageConverters.getConverters());
         }
 
         @Override
         public void configureAsyncSupport(AsyncSupportConfigurer configurer) {
             Long timeout = this.mvcProperties.getAsync().getRequestTimeout();
             if (timeout != null) {
                 configurer.setDefaultTimeout(timeout);
             }
         }
 
         @Override
         public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
             Map<String, MediaType> mediaTypes = this.mvcProperties.getMediaTypes();
             for (Entry<String, MediaType> mediaType : mediaTypes.entrySet()) {
                 configurer.mediaType(mediaType.getKey(), 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(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;
         }
 
         @Bean
         @ConditionalOnProperty(prefix = "spring.mvc", name = "date-format")
         public Formatter<Date> dateFormatter() {
             return new DateFormatter(this.mvcProperties.getDateFormat());
         }
 
         @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 <T> Collection<T> getBeansOfType(Class<T> type) {
             return this.beanFactory.getBeansOfType(type).values();
         }
 
         @Override
         public void addResourceHandlers(ResourceHandlerRegistry registry) {
             if (!this.resourceProperties.isAddMappings()) {
                 logger.debug("Default resource handling disabled");
                 return;
             }
             Integer cachePeriod = this.resourceProperties.getCachePeriod();
             if (!registry.hasMappingForPattern("/webjars/**")) {
                 customizeResourceHandlerRegistration(
                         registry.addResourceHandler("/webjars/**")
                                 .addResourceLocations(
                                         "classpath:/META-INF/resources/webjars/")
                         .setCachePeriod(cachePeriod));
             }
             String staticPathPattern = this.mvcProperties.getStaticPathPattern();
             if (!registry.hasMappingForPattern(staticPathPattern)) {
                 customizeResourceHandlerRegistration(
                         registry.addResourceHandler(staticPathPattern)
                                 .addResourceLocations(
                                         this.resourceProperties.getStaticLocations())
                         .setCachePeriod(cachePeriod));
             }
         }
 
         @Bean
         public WelcomePageHandlerMapping welcomePageHandlerMapping(
                 ResourceProperties resourceProperties) {
             return new WelcomePageHandlerMapping(resourceProperties.getWelcomePage());
         }
 
         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(Ordered.HIGHEST_PRECEDENCE + 1);
                 mapping.setUrlMap(Collections.singletonMap("**/favicon.ico",
                         faviconRequestHandler()));
                 return mapping;
             }
 
             @Bean
             public ResourceHttpRequestHandler faviconRequestHandler() {
                 ResourceHttpRequestHandler requestHandler = new ResourceHttpRequestHandler();
                 requestHandler
                         .setLocations(this.resourceProperties.getFaviconLocations());
                 return requestHandler;
             }
 
         }
 
     }
 
     /**
      * 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<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 ? true
                     : 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 Validator mvcValidator() {
             if (!ClassUtils.isPresent("javax.validation.Validator",
                     getClass().getClassLoader())) {
                 return super.mvcValidator();
             }
             return WebMvcValidator.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<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());
                     }
                 }
             }
         }
 
     }
 
     @Configuration
     @ConditionalOnEnabledResourceChain
     static class ResourceChainCustomizerConfiguration {
 
         @Bean
         public ResourceChainResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCustomizer() {
             return new ResourceChainResourceHandlerRegistrationCustomizer();
         }
 
     }
 
     interface ResourceHandlerRegistrationCustomizer {
 
         void customize(ResourceHandlerRegistration registration);
 
     }
 
     private 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 (strategy.getFixed().isEnabled() || strategy.getContent().isEnabled()) {
                 chain.addResolver(getVersionResourceResolver(strategy));
             }
             if (properties.isGzipped()) {
                 chain.addResolver(new GzipResourceResolver());
             }
             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;
         }
 
     }
 
     static final class WelcomePageHandlerMapping extends AbstractUrlHandlerMapping {
 
         private static final Log logger = LogFactory
                 .getLog(WelcomePageHandlerMapping.class);
 
         private WelcomePageHandlerMapping(Resource welcomePage) {
             if (welcomePage != null) {
                 logger.info("Adding welcome page: " + welcomePage);
                 ParameterizableViewController controller = new ParameterizableViewController();
                 controller.setViewName("forward:index.html");
                 setRootHandler(controller);
                 setOrder(0);
             }
         }
 
         @Override
         public Object getHandlerInternal(HttpServletRequest request) throws Exception {
             for (MediaType mediaType : getAcceptedMediaTypes(request)) {
                 if (mediaType.includes(MediaType.TEXT_HTML)) {
                     return super.getHandlerInternal(request);
                 }
             }
             return null;
         }
 
         private List<MediaType> getAcceptedMediaTypes(HttpServletRequest request) {
             String acceptHeader = request.getHeader(HttpHeaders.ACCEPT);
             return MediaType.parseMediaTypes(
                     StringUtils.hasText(acceptHeader) ? acceptHeader : "*/*");
         }
 
     }
 
 }

 @ConfigurationProperties(prefix = "spring.mvc")
 public class WebMvcProperties {
 
     /**
      * Formatting strategy for message codes (PREFIX_ERROR_CODE, POSTFIX_ERROR_CODE).
      */
     private DefaultMessageCodesResolver.Format messageCodesResolverFormat;
 
     /**
      * Locale to use. By default, this locale is overridden by the "Accept-Language"
      * header.
      */
     private Locale locale;
 
     /**
      * Define how the locale should be resolved.
      */
     private LocaleResolver localeResolver = LocaleResolver.ACCEPT_HEADER;
 
     /**
      * Date format to use (e.g. dd/MM/yyyy).
      */
     private String dateFormat;
 
     /**
      * Dispatch TRACE requests to the FrameworkServlet doService method.
      */
     private boolean dispatchTraceRequest = false;
 
     /**
      * Dispatch OPTIONS requests to the FrameworkServlet doService method.
      */
     private boolean dispatchOptionsRequest = true;
 
     /**
      * If the content of the "default" model should be ignored during redirect scenarios.
      */
     private boolean ignoreDefaultModelOnRedirect = true;
 
     /**
      * If a "NoHandlerFoundException" should be thrown if no Handler was found to process
      * a request.
      */
     private boolean throwExceptionIfNoHandlerFound = false;
 
     /**
      * Enable warn logging of exceptions resolved by a "HandlerExceptionResolver".
      */
     private boolean logResolvedException = false;
 
     /**
      * Maps file extensions to media types for content negotiation, e.g. yml->text/yaml.
      */
     private Map<String, MediaType> mediaTypes = new LinkedHashMap<String, MediaType>();
 
     /**
      * Path pattern used for static resources.
      */
     private String staticPathPattern = "/**";
 
     private final Async async = new Async();
 
     private final Servlet servlet = new Servlet();
 
     private final View view = new View();
 
     public DefaultMessageCodesResolver.Format getMessageCodesResolverFormat() {
         return this.messageCodesResolverFormat;
     }
 
     public void setMessageCodesResolverFormat(
             DefaultMessageCodesResolver.Format messageCodesResolverFormat) {
         this.messageCodesResolverFormat = messageCodesResolverFormat;
     }
 
     public Locale getLocale() {
         return this.locale;
     }
 
     public void setLocale(Locale locale) {
         this.locale = locale;
     }
 
     public LocaleResolver getLocaleResolver() {
         return this.localeResolver;
     }
 
     public void setLocaleResolver(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 Async getAsync() {
         return this.async;
     }
 
     public Servlet getServlet() {
         return this.servlet;
     }
 
     public View getView() {
         return this.view;
     }
 
     public static class Async {
 
         /**
          * Amount of time (in milliseconds) before asynchronous request handling times
          * out. If this value is not set, the default timeout of the underlying
          * implementation is used, e.g. 10 seconds on Tomcat with Servlet 3.
          */
         private Long requestTimeout;
 
         public Long getRequestTimeout() {
             return this.requestTimeout;
         }
 
         public void setRequestTimeout(Long requestTimeout) {
             this.requestTimeout = requestTimeout;
         }
 
     }
 
     public static class Servlet {
 
         /**
          * Load on startup priority of the dispatcher servlet.
          */
         private int loadOnStartup = -1;
 
         public int getLoadOnStartup() {
             return this.loadOnStartup;
         }
 
         public void setLoadOnStartup(int loadOnStartup) {
             this.loadOnStartup = loadOnStartup;
         }
 
     }
 
     public static class View {
 
         /**
          * Spring MVC view prefix.
          */
         private String prefix;
 
         /**
          * Spring MVC view suffix.
          */
         private String suffix;
 
         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 enum LocaleResolver {
 
         /**
          * Always use the configured locale.
          */
         FIXED,
 
         /**
          * Use the "Accept-Language" header or the configured locale if the header is not
          * set.
          */
         ACCEPT_HEADER
 
     }
 
 }

 3.2 接管spring boot的web配置

　　在既需要保留spring boot提供的便利，又需要增加自己的额外的配置的时候，可以定义一个配置类并继承WebMvcConfigurerAdapter，无须使用@EnableWebMvc注解，然后按照spring mvc的配置方法来添加spring boot其他配置。值得指出的是重写addViewControllers方法，并不会覆盖WebMvcConfigurerAdapter中的addViewControllers（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。

 3.3 注册servlet、filter、Listener

　　当使用嵌入式的servlet容器（tomcat、jetty等）时，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、ServletListenerRegistrationBean的bean。

3.4 Tomcat配置

　　关于tomcat的所有属性都在org.springframework.boot.autoconfigure.web.ServerProperties配置类中做了定义，我们只需要在application.Properties配置属性做配置即可。通用的Servlet容器配置都以“server”作为前缀，而tomcat特有的配置都以“server.tomcat”作为前缀。配置tomcat还可以用代码的方式配置，以后再说。