DispatcherServlet初始化过程
DispatcherServlet 本质上是一个 Servlet,所以天然的遵循 Servlet 的生命周期。所以宏观上是 Servlet 生命周期来进行调度。
a>初始化WebApplicationContext
所在类:org.springframework.web.servlet.FrameworkServlet
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 // 创建WebApplicationContext 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. synchronized (this.onRefreshMonitor) { // 刷新WebApplicationContext onRefresh(wac); } } if (this.publishContext) { // Publish the context as a servlet context attribute. // 将IOC容器在应用域共享 String attrName = getServletContextAttributeName(); getServletContext().setAttribute(attrName, wac); } return wac; }
b>创建WebApplicationContext
所在类:org.springframework.web.servlet.FrameworkServlet
protected WebApplicationContext createWebApplicationContext(@Nullable ApplicationContext parent) { Class<?> contextClass = getContextClass(); if (!ConfigurableWebApplicationContext.class.isAssignableFrom(contextClass)) { throw new ApplicationContextException( "Fatal initialization error in servlet with name '" + getServletName() + "': custom WebApplicationContext class [" + contextClass.getName() + "] is not of type ConfigurableWebApplicationContext"); } // 通过反射创建 IOC 容器对象 ConfigurableWebApplicationContext wac = (ConfigurableWebApplicationContext) BeanUtils.instantiateClass(contextClass); wac.setEnvironment(getEnvironment()); // 设置父容器 wac.setParent(parent); String configLocation = getContextConfigLocation(); if (configLocation != null) { wac.setConfigLocation(configLocation); } configureAndRefreshWebApplicationContext(wac); return wac; }
c>DispatcherServlet初始化策略
FrameworkServlet创建WebApplicationContext后,刷新容器,调用onRefresh(wac),此方法在 DispatcherServlet中进行了重写,调用了initStrategies(context)方法,初始化策略,即初始化 DispatcherServlet的各个组件
所在类:org.springframework.web.servlet.DispatcherServlet
protected void initStrategies(ApplicationContext context) { initMultipartResolver(context); initLocaleResolver(context); initThemeResolver(context); initHandlerMappings(context); initHandlerAdapters(context); initHandlerExceptionResolvers(context); initRequestToViewNameTranslator(context); initViewResolvers(context); initFlashMapManager(context); }
标签:WebApplicationContext,初始化,SpringMVC,wac,context,DispatcherServlet,servlet,Config From: https://www.cnblogs.com/ai377377/p/16804231.html