spring mvcソース(一)ウェブコンテナの作成

もっと読む
spring mvcはmvcのオープンソースフレームです.springとは親子関係ですので、シームレスに対応しています.
 
spring mvc入口:
 

    
    
        spring-mvc
        org.springframework.web.servlet.DispatcherServlet
        
            contextConfigLocation
            classpath*:/spring-mvc-servlet.xml
        
        1
    

 spring mvcのweb.xmlでの構成は上述の通りであり、これは標準的なservletの構成であり、入口はDisplatch Servletである.
 
Displatch Servletソースは:
 

public class DispatcherServlet extends FrameworkServlet {
//      ...
}

public abstract class FrameworkServlet extends HttpServletBean {
//      ...s
}

public abstract class HttpServletBean extends HttpServlet
		implements EnvironmentCapable, EnvironmentAware {
//      
}

 Disppatch Servletは上から分かります.HttpServletインターフェースを実現しましたので、設定もservletで構成します.
 
 
一つのservletの初期化はinit()の方法で行われます.まず一番上のクラスHttpServletBenから見て、次はHttpServletBenのinit()の方法の実現です.
 

	@Override
	public final void init() throws ServletException {
		if (logger.isDebugEnabled()) {
			logger.debug("Initializing servlet '" + getServletName() + "'");
		}

		// Set bean properties from init parameters.
		try {
			PropertyValues pvs = new ServletConfigPropertyValues(getServletConfig(), this.requiredProperties);
			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) {
			logger.error("Failed to set bean properties on servlet '" + getServletName() + "'", ex);
			throw ex;
		}

		// Let subclasses do whatever initialization they like.
                //        
		initServletBean();

		if (logger.isDebugEnabled()) {
			logger.debug("Servlet '" + getServletName() + "' configured successfully");
		}
	}

 上記のコードから分かるように、方法の前半はいくつかの初期化構成をしています.initServletBenはFramw orkServletによって書き換えられています.次はFrame ebork ServletのinitServBen()の実現です.
 

	@Override
	protected final void initServletBean() throws ServletException {
		getServletContext().log("Initializing Spring FrameworkServlet '" + getServletName() + "'");
		if (this.logger.isInfoEnabled()) {
			this.logger.info("FrameworkServlet '" + getServletName() + "': initialization started");
		}
		long startTime = System.currentTimeMillis();

		try {
                        //     ，    
			this.webApplicationContext = initWebApplicationContext();
			initFrameworkServlet();
		}
		catch (ServletException ex) {
			this.logger.error("Context initialization failed", ex);
			throw ex;
		}
		catch (RuntimeException ex) {
			this.logger.error("Context initialization failed", ex);
			throw ex;
		}

		if (this.logger.isInfoEnabled()) {
			long elapsedTime = System.currentTimeMillis() - startTime;
			this.logger.info("FrameworkServlet '" + getServletName() + "': initialization completed in " +
					elapsedTime + " ms");
		}
	}

        //       ，  spring mvc     
	protected WebApplicationContext initWebApplicationContext() {
                //     ， spring   
		WebApplicationContext rootContext =
				WebApplicationContextUtils.getWebApplicationContext(getServletContext());
		WebApplicationContext wac = null;

		if (this.webApplicationContext != null) {
			// A context instance was injected at construction time -> use it
			wac = this.webApplicationContext;
			if (wac instanceof ConfigurableWebApplicationContext) {
				ConfigurableWebApplicationContext cwac = (ConfigurableWebApplicationContext) wac;
				if (!cwac.isActive()) {
					// The context has not yet been refreshed -> provide services such as
					// setting the parent context, setting the application context id, etc
					if (cwac.getParent() == null) {
						// The context instance was injected without an explicit parent -> set
						// the root application context (if any; may be null) as the parent
                                                //     ，    spring   
						cwac.setParent(rootContext);
					}
					configureAndRefreshWebApplicationContext(cwac);
				}
			}
		}
		if (wac == null) {
			// No context instance was injected at construction time -> see if one
			// has been registered in the servlet context. If one exists, it is assumed
			// that the parent context (if any) has already been set and that the
			// user has performed any initialization such as setting the context id
			wac = findWebApplicationContext();
		}
		if (wac == null) {
			// No context instance is defined for this servlet -> create a local one
			wac = createWebApplicationContext(rootContext);
		}

		if (!this.refreshEventReceived) {
			// Either the context is not a ConfigurableApplicationContext with refresh
			// support or the context injected at construction time had already been
			// refreshed -> trigger initial onRefresh manually here.
			onRefresh(wac);
		}

		if (this.publishContext) {
			// Publish the context as a servlet context attribute.
			String attrName = getServletContextAttributeName();
			getServletContext().setAttribute(attrName, wac);
			if (this.logger.isDebugEnabled()) {
				this.logger.debug("Published WebApplicationContext of servlet '" + getServletName() +
						"' as ServletContext attribute with name [" + attrName + "]");
			}
		}

		return wac;
	}

上のコードから分かります.spring mvc文脈とspring文脈の関係、spring mvc容器はサブ容器、springの容器は親容器です.だからspring mvcにcontrolerを配置する時、springに配置されたservice類を直接参照できます.したがって、web.xmlの構成では、先にspringの配置を配置してから、spring mvcの配置を配置してください.そうでないと、spring mvcのサブコンテナは親の容器のリソースを使用できません.
 
Fraamew orkServlet類におけるonRefresh()方法は、具体的には実現されていないが、布団類は書き換えられており、サブタイプのDisplatch ServletでonRefresh()方法は以下のように実現される.
 

	@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);
	}

上のコードからDisplatch Servletで容器を更新する時、大量の初期化作業をしました.Resolaver,HandlerMapping,Adapterを初期化しました.
 
初期化Resolaver:
 

	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 + "]");
			}
		}
	}

 デフォルトのrescorverについて:DisplatServletで最初に静的初期化のコードがあります.
 
 

	static {
		// Load default strategy implementations from properties file.
		// This is currently strictly internal and not meant to be customized
		// by application developers.
		try {
			ClassPathResource resource = new ClassPathResource(DEFAULT_STRATEGIES_PATH, DispatcherServlet.class);
			defaultStrategies = PropertiesLoaderUtils.loadProperties(resource);
		}
		catch (IOException ex) {
			throw new IllegalStateException("Could not load 'DispatcherServlet.properties': " + ex.getMessage());
		}
	}

 デフォルトで設定ファイルを読み込みます.Dispactch Servletと同じパスでDEFAULT_.STRATEGIES_PATH;Displatch Servlet.propertiesです.

# 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

 設定ファイルにはデフォルトのResolaver,HandlerMapping,Handler Adapterが配置されています.  Orefsh()メソッドで初期化するコンポーネントにはデフォルトの設定があります.
 
上のコンポーネント初期化は基本的に一つの主要なロジックに従っています.まず容器や資源から探して、見つけられないなら、配置ファイルの中でデフォルトの設定を使用します.
 
上のコードでspring mvcの初期化が完了しました.