DispatcherServlet初始化，继续分析日志
主要部分：
1 23-May-2018 17:47:55.457 INFO [RMI TCP Connection(3)-127.0.0.1] org.springframework.web.servlet.DispatcherServlet.initServletBean FrameworkServlet 'dispatcher': initialization started 2 23-May-2018 17:47:55.463 INFO [RMI TCP Connection(3)-127.0.0.1] org.springframework.web.context.support.XmlWebApplicationContext.prepareRefresh Refreshing WebApplicationContext for namespace 'dispatcher-servlet': startup date [Wed May 23 17:47:55 CST 2018]; parent: Root WebApplicationContext 3 23-May-2018 17:47:55.464 INFO [RMI TCP Connection(3)-127.0.0.1] org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions Loading XML bean definitions from ServletContext resource [/WEB-INF/dispatcher-servlet2.xml] 4 23-May-2018 17:47:56.298 INFO [RMI TCP Connection(3)-127.0.0.1] org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping.register Mapped "{[/user/get],methods=[GET],produces=[text/plain;charset=utf-8]}" onto public java.lang.String com.example.demo.controller.UserController.get(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse) 5 23-May-2018 17:47:56.424 INFO [RMI TCP Connection(3)-127.0.0.1] org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.initControllerAdviceCache Looking for @ControllerAdvice: WebApplicationContext for namespace 'dispatcher-servlet': startup date [Wed May 23 17:47:55 CST 2018]; parent: Root WebApplicationContext 6 23-May-2018 17:47:56.504 INFO [RMI TCP Connection(3)-127.0.0.1] org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.initControllerAdviceCache Looking for @ControllerAdvice: WebApplicationContext for namespace 'dispatcher-servlet': startup date [Wed May 23 17:47:55 CST 2018]; parent: Root WebApplicationContext 7 23-May-2018 17:47:56.686 INFO [RMI TCP Connection(3)-127.0.0.1] org.springframework.web.servlet.DispatcherServlet.initServletBean FrameworkServlet 'dispatcher': initialization completed in 1228 ms
public abstract class FrameworkServlet extends HttpServletBean implements ApplicationContextAware { /** * Overridden method of {@link HttpServletBean}, invoked after any bean properties * have been set. Creates this servlet's WebApplicationContext. */ @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"); } } /** * Initialize and publish the WebApplicationContext for this servlet. * <p>Delegates to {@link #createWebApplicationContext} for actual creation * of the context. Can be overridden in subclasses. * @return the WebApplicationContext instance * @see #FrameworkServlet(WebApplicationContext) * @see #setContextClass * @see #setContextConfigLocation */ protected WebApplicationContext initWebApplicationContext() { 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 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);// 都会执行一次 } 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; } protected void configureAndRefreshWebApplicationContext(ConfigurableWebApplicationContext wac) { if (ObjectUtils.identityToString(wac).equals(wac.getId())) { // The application context id is still set to its original default value // -> assign a more useful id based on available information if (this.contextId != null) { wac.setId(this.contextId); } else { // Generate default id... wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX + ObjectUtils.getDisplayString(getServletContext().getContextPath()) + '/' + getServletName()); } } wac.setServletContext(getServletContext()); wac.setServletConfig(getServletConfig()); wac.setNamespace(getNamespace());// 通过设置namespace的方式，使得日志displayName不同 wac.addApplicationListener(new SourceFilteringListener(wac, new ContextRefreshListener())); // The wac environment's #initPropertySources will be called in any case when the context // is refreshed; do it eagerly here to ensure servlet property sources are in place for // use in any post-processing or initialization that occurs below prior to #refresh ConfigurableEnvironment env = wac.getEnvironment(); if (env instanceof ConfigurableWebEnvironment) { ((ConfigurableWebEnvironment) env).initPropertySources(getServletContext(), getServletConfig()); } postProcessWebApplicationContext(wac); applyInitializers(wac); wac.refresh(); } }
initWebApplicationContext与ContextLoader中的initWebApplicationContext方式极其相似，ContextLoader是默认创建了XmlWebApplicationContext的实例，而这里获得的同样也是XmlWebApplicationContext的实例对象，实际是同一个对象。
同样，LoadBeanDefinitions获取的是web.xml中配置在servlet标签下init-param中key-value
public static <T> Map<String, T> beansOfTypeIncludingAncestors( ListableBeanFactory lbf, Class<T> type, boolean includeNonSingletons, boolean allowEagerInit) throws BeansException { Assert.notNull(lbf, "ListableBeanFactory must not be null");// lbf = new DefaultListableBeanFactory(); Map<String, T> result = new LinkedHashMap<String, T>(4); result.putAll(lbf.getBeansOfType(type, includeNonSingletons, allowEagerInit)); if (lbf instanceof HierarchicalBeanFactory) { HierarchicalBeanFactory hbf = (HierarchicalBeanFactory) lbf; if (hbf.getParentBeanFactory() instanceof ListableBeanFactory) { Map<String, T> parentResult = beansOfTypeIncludingAncestors( (ListableBeanFactory) hbf.getParentBeanFactory(), type, includeNonSingletons, allowEagerInit); for (Map.Entry<String, T> entry : parentResult.entrySet()) { String beanName = entry.getKey(); if (!result.containsKey(beanName) && !hbf.containsLocalBean(beanName)) { result.put(beanName, entry.getValue()); } } } } return result; }
public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFactory implements ConfigurableListableBeanFactory, BeanDefinitionRegistry, Serializable { @Override public <T> Map<String, T> getBeansOfType(Class<T> type, boolean includeNonSingletons, boolean allowEagerInit) throws BeansException { String[] beanNames = getBeanNamesForType(type, includeNonSingletons, allowEagerInit); Map<String, T> result = new LinkedHashMap<String, T>(beanNames.length); for (String beanName : beanNames) { try { result.put(beanName, getBean(beanName, type)); } catch (BeanCreationException ex) { Throwable rootCause = ex.getMostSpecificCause(); if (rootCause instanceof BeanCurrentlyInCreationException) { BeanCreationException bce = (BeanCreationException) rootCause; if (isCurrentlyInCreation(bce.getBeanName())) { if (this.logger.isDebugEnabled()) { this.logger.debug("Ignoring match to currently created bean '" + beanName + "': " + ex.getMessage()); } onSuppressedException(ex); // Ignore: indicates a circular reference when autowiring constructors. // We want to find matches other than the currently created bean itself. continue; } } throw ex; } } return result; } @Override public String[] getBeanNamesForType(Class<?> type, boolean includeNonSingletons, boolean allowEagerInit) { if (!isConfigurationFrozen() || type == null || !allowEagerInit) { return doGetBeanNamesForType(ResolvableType.forRawClass(type), includeNonSingletons, allowEagerInit); } Map<Class<?>, String[]> cache = (includeNonSingletons ? this.allBeanNamesByType : this.singletonBeanNamesByType); String[] resolvedBeanNames = cache.get(type); if (resolvedBeanNames != null) { return resolvedBeanNames; } resolvedBeanNames = doGetBeanNamesForType(ResolvableType.forRawClass(type), includeNonSingletons, true); if (ClassUtils.isCacheSafe(type, getBeanClassLoader())) { cache.put(type, resolvedBeanNames); } return resolvedBeanNames; } private String[] doGetBeanNamesForType(ResolvableType type, boolean includeNonSingletons, boolean allowEagerInit) { List<String> result = new ArrayList<String>(); // Check all bean definitions. private volatile List<String> beanDefinitionNames = new ArrayList<>(256); for (String beanName : this.beanDefinitionNames) {// 集中中的值来自与自动扫描装配 component-scan // Only consider bean as eligible if the bean name // is not defined as alias for some other bean. if (!isAlias(beanName)) { try { RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName); // Only check bean definition if it is complete. if (!mbd.isAbstract() && (allowEagerInit || ((mbd.hasBeanClass() || !mbd.isLazyInit() || isAllowEagerClassLoading())) && !requiresEagerInitForType(mbd.getFactoryBeanName()))) { // In case of FactoryBean, match object created by FactoryBean. boolean isFactoryBean = isFactoryBean(beanName, mbd); BeanDefinitionHolder dbd = mbd.getDecoratedDefinition(); boolean matchFound = (allowEagerInit || !isFactoryBean || (dbd != null && !mbd.isLazyInit()) || containsSingleton(beanName)) && (includeNonSingletons || (dbd != null ? mbd.isSingleton() : isSingleton(beanName))) && isTypeMatch(beanName, type); if (!matchFound && isFactoryBean) { // In case of FactoryBean, try to match FactoryBean instance itself next. beanName = FACTORY_BEAN_PREFIX + beanName; matchFound = (includeNonSingletons || mbd.isSingleton()) && isTypeMatch(beanName, type); } if (matchFound) { result.add(beanName); } } } catch (CannotLoadBeanClassException ex) { if (allowEagerInit) { throw ex; } // Probably contains a placeholder: let's ignore it for type matching purposes. if (this.logger.isDebugEnabled()) { this.logger.debug("Ignoring bean class loading failure for bean '" + beanName + "'", ex); } onSuppressedException(ex); } catch (BeanDefinitionStoreException ex) { if (allowEagerInit) { throw ex; } // Probably contains a placeholder: let's ignore it for type matching purposes. if (this.logger.isDebugEnabled()) { this.logger.debug("Ignoring unresolvable metadata in bean definition '" + beanName + "'", ex); } onSuppressedException(ex); } } } // Check manually registered singletons too. for (String beanName : this.manualSingletonNames) { try { // In case of FactoryBean, match object created by FactoryBean. if (isFactoryBean(beanName)) { if ((includeNonSingletons || isSingleton(beanName)) && isTypeMatch(beanName, type)) { result.add(beanName); // Match found for this bean: do not match FactoryBean itself anymore. continue; } // In case of FactoryBean, try to match FactoryBean itself next. beanName = FACTORY_BEAN_PREFIX + beanName; } // Match raw bean instance (might be raw FactoryBean). if (isTypeMatch(beanName, type)) { result.add(beanName); } } catch (NoSuchBeanDefinitionException ex) { // Shouldn't happen - probably a result of circular reference resolution... if (logger.isDebugEnabled()) { logger.debug("Failed to check manually registered singleton with name '" + beanName + "'", ex); } } } return StringUtils.toStringArray(result); } }