Spring MVCのDisplatch Servlet初期化

Spring MVCを使う このDispactch Servletは、web.xmlにDisplatServletを配置する必要があります.このDisplatServletは、1つのコントローラの具体的な実現と見なされます.コントローラとしての要求はすべてこれによって処理され、転送、マッチング、データ処理を行い、ページによって展示されます.このためDisplatch ServletはSpring MVCの核心部分です.   
      Conttext Loader Listenerの初期化が完了した後、WebコンテナがDispacterServletを初期化し始め、この初期化の起動はweb.xmlにおけるロード順序の定義に関連している.DisplathcerServletは自分の文脈を確立してSpring MVCのBeanを持ちます.この自分のIOC容器を作る時、ServletConteetから自分の文脈を持つ両親の文脈としてルートを得ます.このルートのコンテキストがあったら、自分の持っているコンテキストを初期化して、最後に自分の持っているコンテキストをServlet Contectに保存します.
 
     まず、Dispactch Serlvetの後継関係を見てください.Dispactch ServletはFrame ebork Servletから継承されていますが、Frambork ServetはHttpServletBenから継承されています.
    Displatch Servlet動作は大きく分けて2つの部分に分けられます.初期化部分はinitServletBean()によって開始され、initWebAppliation Conteet()方法でDispactch ServletのinitStrategies方法を呼び出します.この方法では、Displatch ServletはMVCの他の部分を初期化しました.例えば、handleMapping、ViewResoliverです.もう一つの部分は、Httpの要求に応答して、Servletとして、ウェブコンテナはServletのdoGet()とdoPost()の方法を呼び出し、Frame ServletのprocessRequest()の簡単な処理を経た後、Dispactch ServletのdoService()の方法を呼び出し、この方法でDispactchをパッケージ化した.
     ここでは主に初期化部分を紹介します.
    Servletとして、Displatch Servletの起動プロセスとServlet起動プロセスは関連しています.Servletの初期化プロセスでは、Servletのinit方法が呼び出され、初期化されました.
HttppServletBenn.init()->Framweork Servlet.init WebAppleication Conteet()->DisplatServlet.onRefresh().
onRefresh ソースは:
 

	/**
	 * This implementation calls {@link #initStrategies}.
	 */
	@Override
	protected void onRefresh(ApplicationContext context) {
		initStrategies(context);
	}

 initStrategiesのソースコードは以下の通りです.
 
 
 

	protected void initStrategies(ApplicationContext context) {
		//         
		initMultipartResolver(context);
		//        
		initLocaleResolver(context);
		//        
		initThemeResolver(context);
		//   HandlerMappings
		initHandlerMappings(context);
		//    HandlerAdapters
		initHandlerAdapters(context);
		//        
		initHandlerExceptionResolvers(context);
		//            
		initRequestToViewNameTranslator(context);
		//        
		initViewResolvers(context);
		//   FlashMapManager
		initFlashMapManager(context);
	}

     initMultiiprtResoverによって初期化されたマルチメディア解析器は、構成ファイルにmultiiprtResolaverとしてIDが設定されていない場合はマルチメディアプロセッサを提供しない.
 
 
 

/**
	 * Initialize the MultipartResolver used by this class.
	 * <p>If no bean is defined with the given name in the BeanFactory for this namespace,
	 * no multipart handling is provided.
	 */
	private void initMultipartResolver(ApplicationContext context) {
		try {
			this.multipartResolver = context.getBean(MULTIPART_RESOLVER_BEAN_NAME, MultipartResolver.class);
			if (logger.isDebugEnabled()) {
				logger.debug("Using MultipartResolver [" + this.multipartResolver + "]");
			}
		}
		catch (NoSuchBeanDefinitionException ex) {
			// Default is no multipart resolver.
			this.multipartResolver = null;
			if (logger.isDebugEnabled()) {
				logger.debug("Unable to locate MultipartResolver with name '" + MULTIPART_RESOLVER_BEAN_NAME +
						"': no multipart request handling provided");
			}
		}
	}

   init LocareResolaver方式でlocareResolaverの初期化を行い、IDがlocal eResolaverのbeanでない場合はAccept Header LocareResolaverの位置解析器を使用する.

 * Initialize the LocaleResolver used by this class.
	 * <p>If no bean is defined with the given name in the BeanFactory for this namespace,
	 * we default to AcceptHeaderLocaleResolver.
	 */
	private void initLocaleResolver(ApplicationContext context) {
		try {
			this.localeResolver = context.getBean(LOCALE_RESOLVER_BEAN_NAME, LocaleResolver.class);
			if (logger.isDebugEnabled()) {
				logger.debug("Using LocaleResolver [" + this.localeResolver + "]");
			}
		}
		catch (NoSuchBeanDefinitionException ex) {
			// We need to use the default.
			this.localeResolver = getDefaultStrategy(context, LocaleResolver.class);
			if (logger.isDebugEnabled()) {
				logger.debug("Unable to locate LocaleResolver with name '" + LOCALE_RESOLVER_BEAN_NAME +
						"': using default [" + this.localeResolver + "]");
			}
		}
	}

 initThe meResolaverイニシャルテーマ解析器がない場合は、IDを指定するthemeResolaverのbeanが配置されていません. FixedThe meResolaverを使用します.

	/**
	 * Initialize the ThemeResolver used by this class.
	 * <p>If no bean is defined with the given name in the BeanFactory for this namespace,
	 * we default to a FixedThemeResolver.
	 */
	private void initThemeResolver(ApplicationContext context) {
		try {
			this.themeResolver = context.getBean(THEME_RESOLVER_BEAN_NAME, ThemeResolver.class);
			if (logger.isDebugEnabled()) {
				logger.debug("Using ThemeResolver [" + this.themeResolver + "]");
			}
		}
		catch (NoSuchBeanDefinitionException ex) {
			// We need to use the default.
			this.themeResolver = getDefaultStrategy(context, ThemeResolver.class);
			if (logger.isDebugEnabled()) {
				logger.debug(
						"Unable to locate ThemeResolver with name '" + THEME_RESOLVER_BEAN_NAME + "': using default [" +
								this.themeResolver + "]");
			}
		}
	}

 HandlerMappingを初期化し、このhandle Mappingの役割は、Http要求に対応するコントローラを見つけて、これらのコントローラを利用してhttp要求のデータ処理を完了することである.これらのコントローラとhttpの要求は対応します.Displatch ServletにおけるhandleMappingの初期化過程における具体的な実現は以下の通りである.HandlerMappingの初期化過程で、Beanプロファイルに配置されたhandler MappingをIOC容器から取り出します.

	/**
	 * Initialize the HandlerMappings used by this class.
	 * <p>If no HandlerMapping beans are defined in the BeanFactory for this namespace,
	 * we default to BeanNameUrlHandlerMapping.
	 */
	private void initHandlerMappings(ApplicationContext context) {
		this.handlerMappings = null;
	
		if (this.detectAllHandlerMappings) {
			//                    HandlerMappings
			Map<String, HandlerMapping> matchingBeans =
					BeanFactoryUtils.beansOfTypeIncludingAncestors(context, HandlerMapping.class, true, false);
			//  matchingBeans  map    ，       ArrayList
			if (!matchingBeans.isEmpty()) {
				this.handlerMappings = new ArrayList<HandlerMapping>(matchingBeans.values());
				//       
				OrderComparator.sort(this.handlerMappings);
			}
		}
		else {
			try {
			    //            HandlerMapping
				HandlerMapping hm = context.getBean(HANDLER_MAPPING_BEAN_NAME, HandlerMapping.class);
				this.handlerMappings = Collections.singletonList(hm);
			}
			catch (NoSuchBeanDefinitionException ex) {
				// Ignore, we'll add a default HandlerMapping later.
			}
		}

		// Ensure we have at least one HandlerMapping, by registering
		// a default HandlerMapping if no other mappings are found.
		if (this.handlerMappings == null) {
			//       HandlerMapping       HandlerMapping   
			this.handlerMappings = getDefaultStrategies(context, HandlerMapping.class);
			if (logger.isDebugEnabled()) {
				logger.debug("No HandlerMappings found in servlet '" + getServletName() + "': using default");
			}
		}
	}

     上記の処理過程に進みました.handleMappingは初期化されました.handerMappingではすでにBenDefinitionに配置されたマッピング関係を取得しました.
 
      inithandler Adaptersによる初期化は、HandlerAdapterが配置されていない場合は、SimpleController Handler Adapterを使用します.
 

/**
	 * Initialize the HandlerAdapters used by this class.
	 * <p>If no HandlerAdapter beans are defined in the BeanFactory for this namespace,
	 * we default to SimpleControllerHandlerAdapter.
	 */
	private void initHandlerAdapters(ApplicationContext context) {
		this.handlerAdapters = null;

		if (this.detectAllHandlerAdapters) {
			// Find all HandlerAdapters in the ApplicationContext, including ancestor contexts.
			Map<String, HandlerAdapter> matchingBeans =
					BeanFactoryUtils.beansOfTypeIncludingAncestors(context, HandlerAdapter.class, true, false);
			if (!matchingBeans.isEmpty()) {
				this.handlerAdapters = new ArrayList<HandlerAdapter>(matchingBeans.values());
				// We keep HandlerAdapters in sorted order.
				OrderComparator.sort(this.handlerAdapters);
			}
		}
		else {
			try {
				HandlerAdapter ha = context.getBean(HANDLER_ADAPTER_BEAN_NAME, HandlerAdapter.class);
				this.handlerAdapters = Collections.singletonList(ha);
			}
			catch (NoSuchBeanDefinitionException ex) {
				// Ignore, we'll add a default HandlerAdapter later.
			}
		}

		// Ensure we have at least some HandlerAdapters, by registering
		// default HandlerAdapters if no other adapters are found.
		if (this.handlerAdapters == null) {
			this.handlerAdapters = getDefaultStrategies(context, HandlerAdapter.class);
			if (logger.isDebugEnabled()) {
				logger.debug("No HandlerAdapters found in servlet '" + getServletName() + "': using default");
			}
		}
	}

  初期化された異常プロセッサは、設定されていない場合、アンディラウExceptionResolaverのBeanを指定します.デフォルトでは異常プロセッサはありません.

	/**
	 * Initialize the HandlerExceptionResolver used by this class.
	 * <p>If no bean is defined with the given name in the BeanFactory for this namespace,
	 * we default to no exception resolver.
	 */
	private void initHandlerExceptionResolvers(ApplicationContext context) {
		this.handlerExceptionResolvers = null;

		if (this.detectAllHandlerExceptionResolvers) {
			// Find all HandlerExceptionResolvers in the ApplicationContext, including ancestor contexts.
			Map<String, HandlerExceptionResolver> matchingBeans = BeanFactoryUtils
					.beansOfTypeIncludingAncestors(context, HandlerExceptionResolver.class, true, false);
			if (!matchingBeans.isEmpty()) {
				this.handlerExceptionResolvers = new ArrayList<HandlerExceptionResolver>(matchingBeans.values());
				// We keep HandlerExceptionResolvers in sorted order.
				OrderComparator.sort(this.handlerExceptionResolvers);
			}
		}
		else {
			try {
				HandlerExceptionResolver her =
						context.getBean(HANDLER_EXCEPTION_RESOLVER_BEAN_NAME, HandlerExceptionResolver.class);
				this.handlerExceptionResolvers = Collections.singletonList(her);
			}
			catch (NoSuchBeanDefinitionException ex) {
				// Ignore, no HandlerExceptionResolver is fine too.
			}
		}

		// Ensure we have at least some HandlerExceptionResolvers, by registering
		// default HandlerExceptionResolvers if no other resolvers are found.
		if (this.handlerExceptionResolvers == null) {
			this.handlerExceptionResolvers = getDefaultStrategies(context, HandlerExceptionResolver.class);
			if (logger.isDebugEnabled()) {
				logger.debug("No HandlerExceptionResolvers found in servlet '" + getServletName() + "': using default");
			}
		}
	}

 
初期化要求はビュー名の変換器に、設定しない場合はデフォルトの変換器を使用する.

/**
	 * Initialize the RequestToViewNameTranslator used by this servlet instance.
	 * <p>If no implementation is configured then we default to DefaultRequestToViewNameTranslator.
	 */
	private void initRequestToViewNameTranslator(ApplicationContext context) {
		try {
			this.viewNameTranslator =
					context.getBean(REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME, RequestToViewNameTranslator.class);
			if (logger.isDebugEnabled()) {
				logger.debug("Using RequestToViewNameTranslator [" + this.viewNameTranslator + "]");
			}
		}
		catch (NoSuchBeanDefinitionException ex) {
			// We need to use the default.
			this.viewNameTranslator = getDefaultStrategy(context, RequestToViewNameTranslator.class);
			if (logger.isDebugEnabled()) {
				logger.debug("Unable to locate RequestToViewNameTranslator with name '" +
						REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME + "': using default [" + this.viewNameTranslator +
						"]");
			}
		}
	}

  ビューの解像度を初期化します.ビューの解像度を設定していない場合は、デフォルトのInternalResource View Resolaverを使用します.

/**
	 * Initialize the ViewResolvers used by this class.
	 * <p>If no ViewResolver beans are defined in the BeanFactory for this
	 * namespace, we default to InternalResourceViewResolver.
	 */
	private void initViewResolvers(ApplicationContext context) {
		this.viewResolvers = null;

		if (this.detectAllViewResolvers) {
			// Find all ViewResolvers in the ApplicationContext, including ancestor contexts.
			Map<String, ViewResolver> matchingBeans =
					BeanFactoryUtils.beansOfTypeIncludingAncestors(context, ViewResolver.class, true, false);
			if (!matchingBeans.isEmpty()) {
				this.viewResolvers = new ArrayList<ViewResolver>(matchingBeans.values());
				// We keep ViewResolvers in sorted order.
				OrderComparator.sort(this.viewResolvers);
			}
		}
		else {
			try {
				ViewResolver vr = context.getBean(VIEW_RESOLVER_BEAN_NAME, ViewResolver.class);
				this.viewResolvers = Collections.singletonList(vr);
			}
			catch (NoSuchBeanDefinitionException ex) {
				// Ignore, we'll add a default ViewResolver later.
			}
		}

		// Ensure we have at least one ViewResolver, by registering
		// a default ViewResolver if no other resolvers are found.
		if (this.viewResolvers == null) {
			this.viewResolvers = getDefaultStrategies(context, ViewResolver.class);
			if (logger.isDebugEnabled()) {
				logger.debug("No ViewResolvers found in servlet '" + getServletName() + "': using default");
			}
		}
	}

 デフォルトの設定を取得し、まずインターフェースの名前を取得し、DisplatServlert.propertiesのプロファイルからvalueを読み出して文字列配列に分割します.

/**
	 * Create a List of default strategy objects for the given strategy interface.
	 * <p>The default implementation uses the "DispatcherServlet.properties" file (in the same
	 * package as the DispatcherServlet class) to determine the class names. It instantiates
	 * the strategy objects through the context's BeanFactory.
	 * @param context the current WebApplicationContext
	 * @param strategyInterface the strategy interface
	 * @return the List of corresponding strategy objects
	 */
	@SuppressWarnings("unchecked")
	protected <T> List<T> getDefaultStrategies(ApplicationContext context, Class<T> strategyInterface) {
		String key = strategyInterface.getName();
		String value = defaultStrategies.getProperty(key);
		if (value != null) {
			String[] classNames = StringUtils.commaDelimitedListToStringArray(value);
			List<T> strategies = new ArrayList<T>(classNames.length);
			for (String className : classNames) {
				try {
					Class<?> clazz = ClassUtils.forName(className, DispatcherServlet.class.getClassLoader());
					Object strategy = createDefaultStrategy(context, clazz);
					strategies.add((T) strategy);
				}
				catch (ClassNotFoundException ex) {
					throw new BeanInitializationException(
							"Could not find DispatcherServlet's default strategy class [" + className +
									"] for interface [" + key + "]", ex);
				}
				catch (LinkageError err) {
					throw new BeanInitializationException(
							"Error loading DispatcherServlet's default strategy class [" + className +
									"] for interface [" + key + "]: problem with class file or dependent class", err);
				}
			}
			return strategies;
		}
		else {
			return new LinkedList<T>();
		}
	}

 
 
 
Displatch Serlvet.properties

    # Default implementation classes for DispatcherServlet's strategy interfaces.
# Used as fallback when no matching beans are found in the DispatcherServlet context.
# Not meant to be customized by application developers.

org.springframework.web.servlet.LocaleResolver=org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver

org.springframework.web.servlet.ThemeResolver=org.springframework.web.servlet.theme.FixedThemeResolver

org.springframework.web.servlet.HandlerMapping=org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping,\
	org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping

org.springframework.web.servlet.HandlerAdapter=org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter,\
	org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter,\
	org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter

org.springframework.web.servlet.HandlerExceptionResolver=org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerExceptionResolver,\
	org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver,\
	org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver

org.springframework.web.servlet.RequestToViewNameTranslator=org.springframework.web.servlet.view.DefaultRequestToViewNameTranslator

org.springframework.web.servlet.ViewResolver=org.springframework.web.servlet.view.InternalResourceViewResolver

org.springframework.web.servlet.FlashMapManager=org.springframework.web.servlet.support.SessionFlashMapManager