SpringMVC源码-SpringMVC框架中Spring父容器和SpringMVC子容器加载的流程以及SpringMVC九大内置组件的初始
一、Spring父容器启动
SpringMVC 的项目结构如下:
applicationContext.xml spring的配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="com.mashibing"></context:component-scan>
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="suffix" value=".jsp"></property>
<property name="prefix" value="/WEB-INF/jsp/"></property>
</bean>
</beans>
spring-config.xml SpringMVC 配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id = "user" class="com.mashibing.bean.User">
<property name="username" value="zhangsan"></property>
<property name="age" value="12"></property>
</bean>
</beans>
web.xml该配置文件是在tomcat启动的时候加载的
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-config.xml</param-value>
</context-param><!--Spring加载的配置文件-->
<servlet>
<servlet-name>mvc-test</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class><!--Springmvc加载启动是放在servlet中执行的 servlet的生命周期 init在HttpServletBean service destory-->
<!--SpringMVC配置文件-->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
<async-supported>true</async-supported>
</servlet>
<servlet-mapping>
<servlet-name>mvc-test</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener><!--监听器 方法的入口 这里是tomcat调用的 -->
</web-app>
<!--配置文件可写监听器 过滤器这些 springmvc是基于spring进行扩展 启动springmvc之前先把spring启动起来 先启动tomcat容器 -->
ContextLoaderListener 的初始化和实例化是tomcat容器加载web.xml文件的时候完成的，ContextLoaderListener 类下的contextInitialized初始化根web应用程序上下文。
spring是父容器和springmvc子容器两个容器的作用是为了数据的隔离，子容器有parentFactory
此链路执行开始初始化web.xml文件的监听器listener类ContextLoaderListener
<init>:56, ContextLoaderListener (org.springframework.web.context)
newInstance0:-1, NativeConstructorAccessorImpl (sun.reflect)
newInstance:62, NativeConstructorAccessorImpl (sun.reflect)
newInstance:45, DelegatingConstructorAccessorImpl (sun.reflect)
newInstance:423, Constructor (java.lang.reflect)
newInstance:150, DefaultInstanceManager (org.apache.catalina.core)
listenerStart:4691, StandardContext (org.apache.catalina.core)
startInternal:5230, StandardContext (org.apache.catalina.core)
start:183, LifecycleBase (org.apache.catalina.util)
addChildInternal:726, ContainerBase (org.apache.catalina.core)
addChild:698, ContainerBase (org.apache.catalina.core)
addChild:696, StandardHost (org.apache.catalina.core)
manageApp:1783, HostConfig (org.apache.catalina.startup)
invoke0:-1, NativeMethodAccessorImpl (sun.reflect)
invoke:62, NativeMethodAccessorImpl (sun.reflect)
invoke:43, DelegatingMethodAccessorImpl (sun.reflect)
invoke:498, Method (java.lang.reflect)
invoke:293, BaseModelMBean (org.apache.tomcat.util.modeler)
invoke:819, DefaultMBeanServerInterceptor (com.sun.jmx.interceptor)
invoke:801, JmxMBeanServer (com.sun.jmx.mbeanserver)
createStandardContext:460, MBeanFactory (org.apache.catalina.mbeans)
createStandardContext:408, MBeanFactory (org.apache.catalina.mbeans)
invoke0:-1, NativeMethodAccessorImpl (sun.reflect)
invoke:62, NativeMethodAccessorImpl (sun.reflect)
invoke:43, DelegatingMethodAccessorImpl (sun.reflect)
invoke:498, Method (java.lang.reflect)
invoke:293, BaseModelMBean (org.apache.tomcat.util.modeler)
invoke:819, DefaultMBeanServerInterceptor (com.sun.jmx.interceptor)
invoke:801, JmxMBeanServer (com.sun.jmx.mbeanserver)
invoke:468, MBeanServerAccessController (com.sun.jmx.remote.security)
doOperation:1468, RMIConnectionImpl (javax.management.remote.rmi)
access$300:76, RMIConnectionImpl (javax.management.remote.rmi)
run:1309, RMIConnectionImpl$PrivilegedOperation (javax.management.remote.rmi)
doPrivileged:-1, AccessController (java.security)
doPrivilegedOperation:1408, RMIConnectionImpl (javax.management.remote.rmi)
invoke:829, RMIConnectionImpl (javax.management.remote.rmi)
invoke0:-1, NativeMethodAccessorImpl (sun.reflect)
invoke:62, NativeMethodAccessorImpl (sun.reflect)
invoke:43, DelegatingMethodAccessorImpl (sun.reflect)
invoke:498, Method (java.lang.reflect)
dispatch:346, UnicastServerRef (sun.rmi.server)
run:200, Transport$1 (sun.rmi.transport)
run:197, Transport$1 (sun.rmi.transport)
doPrivileged:-1, AccessController (java.security)
serviceCall:196, Transport (sun.rmi.transport)
handleMessages:568, TCPTransport (sun.rmi.transport.tcp)
run0:826, TCPTransport$ConnectionHandler (sun.rmi.transport.tcp)
lambda$run$0:683, TCPTransport$ConnectionHandler (sun.rmi.transport.tcp)
run:-1, 393312068 (sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$$Lambda$25)
doPrivileged:-1, AccessController (java.security)
run:682, TCPTransport$ConnectionHandler (sun.rmi.transport.tcp)
runWorker:1142, ThreadPoolExecutor (java.util.concurrent)
run:617, ThreadPoolExecutor$Worker (java.util.concurrent)
run:748, Thread (java.lang)
调用ContextLoaderListener构造函数
监听事件开始执行，初始化根web应用程序上下文。
event.getServletContext()的结果：包含web.xml文件的contextConfigLocation
<context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:spring-config.xml</param-value> </context-param>，获取到spring需要的配置文件，接下来开始执行spring容器的启动
ContextLoader##initWebApplicationContext
/**
* Initialize Spring's web application context for the given servlet context,为给定的servlet上下文初始化Spring的web应用程序上下文。
* using the application context provided at construction time, or creating a new one使用在构造时提供的应用程序上下文，
* according to the "{@link #CONTEXT_CLASS_PARAM contextClass}" and 或根据“{@link CONTEXT_CLASS_PARAM contextClass}”和“{@link CONFIG_LOCATION_PARAM contextConfigLocation}”上下文参数创建一个新上下文。
* "{@link #CONFIG_LOCATION_PARAM contextConfigLocation}" context-params.
* @param servletContext current servlet context
* @return the new WebApplicationContext
* @see #ContextLoader(WebApplicationContext)
* @see #CONTEXT_CLASS_PARAM
* @see #CONFIG_LOCATION_PARAM
*/
public WebApplicationContext initWebApplicationContext(ServletContext servletContext) {
if (servletContext.getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE) != null) {
// web.xml中存在多次ContextLoader定义
throw new IllegalStateException(
"Cannot initialize context because there is already a root application context present - " +
"check whether you have multiple ContextLoader* definitions in your web.xml!");
}
servletContext.log("Initializing Spring root WebApplicationContext");
Log logger = LogFactory.getLog(ContextLoader.class);
if (logger.isInfoEnabled()) {
logger.info("Root WebApplicationContext: initialization started");
}
long startTime = System.currentTimeMillis();
try {
// Store context in local instance variable, to guarantee that
// it is available on ServletContext shutdown. 将上下文存储在本地实例变量中，以保证它在ServletContext关闭时可用
if (this.context == null) {//this是代指监听器 第一进去是null
// 初始化context，第一次执行的时候获取到一个root webApplicationcontext 是在XmlWebApplicationContext的父类AbstractRefreshableWebApplicationContext构造方法setDisplayName中赋值为root webApplicationcontext
this.context = createWebApplicationContext(servletContext);
}
if (this.context instanceof ConfigurableWebApplicationContext) {
ConfigurableWebApplicationContext cwac = (ConfigurableWebApplicationContext) this.context;
if (!cwac.isActive()) {//判断是否激活 上下文尚未刷新->提供诸如设置父上下文、设置应用程序上下文id等服务
// 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 -> context实例被注入时没有显式的父元素->
// determine parent for root web application context, if any. 确定web应用程序根上下文的父元素(如果有的话)。
ApplicationContext parent = loadParentContext(servletContext);
cwac.setParent(parent);//子类容器也会调用 会把父容器设置进去的
}
configureAndRefreshWebApplicationContext(cwac, servletContext);//refresh刷新
}
}
// 将创建的context对象记录在servletContext中,创建并且准备好了spring容器
servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, this.context);
ClassLoader ccl = Thread.currentThread().getContextClassLoader();
if (ccl == ContextLoader.class.getClassLoader()) {
currentContext = this.context;
}
else if (ccl != null) {
currentContextPerThread.put(ccl, this.context);
}
if (logger.isInfoEnabled()) {
long elapsedTime = System.currentTimeMillis() - startTime;
logger.info("Root WebApplicationContext initialized in " + elapsedTime + " ms");
}
return this.context;//IOC容器准备好勒 原生自带的spring容器
}
catch (RuntimeException | Error ex) {
logger.error("Context initialization failed", ex);
servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, ex);
throw ex;
}
}
createWebApplicationContext
初始化context，第一次执行的时候获取到一个root webApplicationcontext 是在XmlWebApplicationContext的父类AbstractRefreshableWebApplicationContext构造方法setDisplayName中赋值displayName为root webApplicationcontext
protected WebApplicationContext createWebApplicationContext(ServletContext sc) {
// 获取contextClass的Class对象
Class<?> contextClass = determineContextClass(sc);
// 如果是自定义的contextClass对象，那么必须要实现ConfigurableWebApplicationContext此接口，否则无法直接运行
if (!ConfigurableWebApplicationContext.class.isAssignableFrom(contextClass)) {
throw new ApplicationContextException("Custom context class [" + contextClass.getName() +
"] is not of type [" + ConfigurableWebApplicationContext.class.getName() + "]");
}
return (ConfigurableWebApplicationContext) BeanUtils.instantiateClass(contextClass);//进行实例化
}
XmlWebApplicationContext类图:
initWebApplicationContext方法的loadParentContext:确定web应用程序根上下文的父元素(如果有的话)。子容器启动的时候会获取到父类放置进去
ContextLoader的configureAndRefreshWebApplicationContext
protected void configureAndRefreshWebApplicationContext(ConfigurableWebApplicationContext wac, ServletContext sc) {
if (ObjectUtils.identityToString(wac).equals(wac.getId())) {
// The application context id is still set to its original default value 应用程序上下文id仍然设置为其原始默认值
// -> assign a more useful id based on available information 根据可用信息分配一个更有用的id
String idParam = sc.getInitParameter(CONTEXT_ID_PARAM);//CONTEXT_ID_PARAM=contextId
if (idParam != null) {
wac.setId(idParam);
}
else {
// Generate default id... 生成唯一标识
wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX +
ObjectUtils.getDisplayString(sc.getContextPath()));
}
}
wac.setServletContext(sc);//
String configLocationParam = sc.getInitParameter(CONFIG_LOCATION_PARAM);//web.xml文件配置的 contextConfigLocation = classpath:spring-config.xml
if (configLocationParam != null) {
wac.setConfigLocation(configLocationParam);//设置要加载的spring配置文件
}
//当上下文被刷新时，wac环境的initpropertsources将在任何情况下被调用;在这里急切地确保servlet属性源在任何后处理或在刷新之前发生的初始化中使用
// 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) {//将基于{@code Servlet}的{@link StubPropertySource存根属性源}替换为使用给定的{@code servletContext}和{@code servletConfig}对象填充的实际实例。<p>此方法是幂等的，因为它可以被调用任意次数，但将用相应的实际属性源执行一次且仅一次的存根属性源替换。
((ConfigurableWebEnvironment) env).initPropertySources(sc, null);
}
customizeContext(sc, wac);//定制beanFactory，设置相关属性，包括是否允许覆盖同名称的不同定义的对象以及循环依赖 wac.refresh()#refresh#obtainFreshBeanFactory#refreshBeanFactory
wac.refresh();//AbstractApplicationContext里执行调用 这步执行之后 spring容器启动成功
}
读取到spring加载需要的配置文件 准备执行spring的刷新方法
wac.refresh();AbstractApplicationContext里执行调用 这步执行之后 spring容器启动成功
postProcessBeanFactory(beanFactory);//spring项目没实现 在springMvc中启动spring会有 AbstractRefreshableWebApplicationContext 实现类
finishRefresh(); 完成刷新过程，通知生命周期处理器lifecycleProcessor刷新过程，同时发出ContextRefreshEvent通知别人，下面的publishEvent方法 将给定事件发布到所有监听器
wac.refresh执行结束之后可以看到spring配置文件的配置的bean标签被假造到一级缓存对象中去
user对象实例化初始化结束了
后续将创建的context对象记录在servletContext中,创建并且准备好了spring容器
至此spring容器启动完成，接下来开始加载springmvc容器。
二、SpringMVC子容器加载
SpringMVC是严格尊重servlet的生命周期的，初始化就是在init方法中。
<servlet>
<servlet-name>mvc-test</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class><!--Springmvc加载启动是放在servlet中执行的 servlet的生命周期 init在HttpServletBean service destory-->
<!--SpringMVC配置文件-->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
<async-supported>true</async-supported>
</servlet>
servlet相关的类图如下:HttpServletBean的加载实例化初始化时在tomcat容器中进行完成的
init
/**
* Map config parameters onto bean properties of this servlet 将配置参数映射到这个servlet的bean属性上，
* , and invoke subclass initialization.并调用子类初始化。
* @throws ServletException if bean properties are invalid (or required
* properties are missing), or if subclass initialization fails.如果bean属性无效(或者缺少必需的属性)，或者子类初始化失败。
*/
@Override
public final void init() throws ServletException {//该方法是在tomcat 容器中调用的
// Set bean properties from init parameters.
// 将servlet中配置的init-param参数封装到pvs变量中 contextConfigLocation:classpath:applicationContext.xml
PropertyValues pvs = new ServletConfigPropertyValues(getServletConfig(), this.requiredProperties);
if (!pvs.isEmpty()) {
try {
// 将当前的servlet对象转化成BeanWrapper对象，从而能够以spring的方法来将pvs注入到该beanWrapper中
BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(this);//this是DispatcherServlet
ResourceLoader resourceLoader = new ServletContextResourceLoader(getServletContext());
// 注册自定义属性编辑器，一旦有Resource类型的属性，将会使用ResourceEditor进行解析
bw.registerCustomEditor(Resource.class, new ResourceEditor(resourceLoader, getEnvironment()));
// 模板方法，可以在子类调用，做一些初始化工作，bw代表的是DispatcherServlet
initBeanWrapper(bw);
// 以spring的方式来将pvs注入到该beanWrapper对象中,将配置的初始化值（contextConfigLocation）设置到DispatcherServlet
bw.setPropertyValues(pvs, true);
}
catch (BeansException ex) {
if (logger.isErrorEnabled()) {
logger.error("Failed to set bean properties on servlet '" + getServletName() + "'", ex);
}
throw ex;
}
}
// Let subclasses do whatever initialization they like.
// 模板方法，子类初始化的入口方法，查看FrameworkServlet#initServletBean方法
initServletBean();
}
进入FrameworkServlet类的initServletBean方法
FrameworkServlet类下的initServletBean
/**{@link HttpServletBean}的重写方法，在任何bean属性设置后调用。创建这个servlet的WebApplicationContext。
* 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 " + getClass().getSimpleName() + " '" + getServletName() + "'");
if (logger.isInfoEnabled()) {
logger.info("Initializing Servlet '" + getServletName() + "'");
}
// 记录开启时间
long startTime = System.currentTimeMillis();
try {
// 创建或刷新WebApplicationContext实例并对servlet功能所使用的变量进行初始化
this.webApplicationContext = initWebApplicationContext();
// 模板方法，空实现，留给子类扩展
initFrameworkServlet();
}
catch (ServletException | RuntimeException ex) {
logger.error("Context initialization failed", ex);
throw ex;
}
if (logger.isDebugEnabled()) {
String value = this.enableLoggingRequestDetails ?
"shown which may lead to unsafe logging of potentially sensitive data" :
"masked to prevent unsafe logging of potentially sensitive data";
logger.debug("enableLoggingRequestDetails='" + this.enableLoggingRequestDetails +
"': request parameters and headers will be " + value);
}
if (logger.isInfoEnabled()) {
logger.info("Completed initialization in " + (System.currentTimeMillis() - startTime) + " ms");
}
}
FrameworkServlet类initWebApplicationContext方法
/**
* 此处同学们需要知道一个原理，所有的前后端交互的框架都是以servlet为基础的，所以在使用springmvc的时候，默认会把自己的容器设置成ServletContext
* 的属性，默认根容器的key为WebApplicaitonContext.Root,定义在WebApplicationContext中，所以在获取的时候只需要调用ServletContext.getAttribute即可
*
*
* 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() {
// 获得根webApplicationContext对象
WebApplicationContext rootContext =
WebApplicationContextUtils.getWebApplicationContext(getServletContext());
// 获得webApplicationContext wac对象
WebApplicationContext wac = null;
// 如果构造方法中已经传入webApplicationContext属性，则直接使用
// 此方式主要用于servlet3.0之后的环境，也就是说可以通过ServletContext.addServlet的方法注册servlet，此时就可以在创建FrameworkServlet和
// 其子类的时候通过构造方法传递已经准备好的webApplicationContext
if (this.webApplicationContext != null) {
// A context instance was injected at construction time 在构造时注入了上下文实例 -> use it
wac = this.webApplicationContext;
// 如果是ConfigurationWebApplicationContext类型，并且未激活，则进行初始化
if (wac instanceof ConfigurableWebApplicationContext) {
ConfigurableWebApplicationContext cwac = (ConfigurableWebApplicationContext) wac;
// 未激活
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);
}
// 配置和刷新上下文环境
configureAndRefreshWebApplicationContext(cwac);
}
}
}
// 从servletContext获取对应的webApplicationContext对象
// 此方式需要在配置Servlet的时候将servletContext中的webApplicationContext的name配置到contextAttribute属性就可以
/*
<servlet>
<servlet-name>mvc-test</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--SpringMVC配置文件-->
<init-param>
<param-name>contextAttribute</param-name>
<param-value>mashibing</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
*/
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();
}
// 当前面两种方式都无效的情况下会创建一个webApplicationContext对象，一般情况下都是使用这样的方式
if (wac == null) {
// No context instance is defined for this servlet -> create a local one
wac = createWebApplicationContext(rootContext);
}
// 将contextRefreshedEvent事件没有触发时调用此方法，模板方法，可以在子类重写
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) {
onRefresh(wac);
}
}
// 将applicationContext设置到servletContext中
if (this.publishContext) {
// Publish the context as a servlet context attribute.
String attrName = getServletContextAttributeName();
getServletContext().setAttribute(attrName, wac);
}
return wac;
}
这里把spring容器设置为springmvc的父容器，看parent的一级缓存有spring配置文件的bean标签实例化的对象就可以知道了
ServletContext servlet的上下文对象，包含整个web.xml文件的配置
ServletConfig 被某个servlet持有，对应的servlet中的配置属性
添加监听器以及对应监听器的监听的事件类型
添加监听器sourceFilteringListener到wac中,实际监听的是ContextRefreshListener所监听的事件，监听ContextRefreshedEvent事件
当接收到消息之后会调用onApplicationEvent方法，调用onRefresh方法，并将refreshEventReceived标志设置为true，表示已经refresh过
this.applicationListeners.add(listener);AbstractApplicationContext的applicationListeners集合有了一个监听器
ContextRefreshListener
/**
* Callback that receives refresh events from this servlet's WebApplicationContext.从servlet的WebApplicationContext接收刷新事件的回调
* <p>The default implementation calls {@link #onRefresh},
* triggering a refresh of this servlet's context-dependent state.默认的实现调用{@link onRefresh}，触发这个servlet的上下文依赖状态的刷新。
* @param event the incoming ApplicationContext event 传入的ApplicationContext事件
*/
public void onApplicationEvent(ContextRefreshedEvent event) {
// 标记 refreshEventReceived 为true
this.refreshEventReceived = true;
synchronized (this.onRefreshMonitor) {
// 处理事件中的 ApplicationContext 对象，空实现，子类DispatcherServlet会实现
onRefresh(event.getApplicationContext());
}
}
**wac.refresh();**开始刷新wac,从而初始化wac，现在完成SpringMVC的容器创建，加载配置文件生成对象
@Override
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// Prepare this context for refreshing.
/**
* 前戏，做容器刷新前的准备工作
* 1、设置容器的启动时间
* 2、设置活跃状态为true
* 3、设置关闭状态为false
* 4、获取Environment对象，并加载当前系统的属性值到Environment对象中
* 5、准备监听器和事件的集合对象，默认为空的集合
*/
prepareRefresh();
// Tell the subclass to refresh the internal bean factory. 告诉子类刷新内部bean工厂。
// 创建容器对象：DefaultListableBeanFactory
// 加载xml配置文件的属性值到当前工厂中，最重要的就是BeanDefinition
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// Prepare the bean factory for use in this context.
// beanFactory的准备工作，对各种属性进行填充
prepareBeanFactory(beanFactory);
try {
// Allows post-processing of the bean factory in context subclasses.
// 子类覆盖方法做额外的处理，此处我们自己一般不做任何扩展工作，但是可以查看web中的代码，是有具体实现的
postProcessBeanFactory(beanFactory);//spring项目没实现 在springMvc中启动spring会有 AbstractRefreshableWebApplicationContext 实现类
// Invoke factory processors registered as beans in the context.
// 调用各种beanFactory处理器
invokeBeanFactoryPostProcessors(beanFactory);
// Register bean processors that intercept bean creation.
// 注册bean处理器，这里只是注册功能，真正调用的是getBean方法
registerBeanPostProcessors(beanFactory);
// Initialize message source for this context.
// 为上下文初始化message源，即不同语言的消息体，国际化处理,在springmvc的时候通过国际化的代码重点讲
initMessageSource();
// Initialize event multicaster for this context.
// 初始化事件监听多路广播器
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
// 留给子类来初始化其他的bean
onRefresh();//AbstractRefreshableWebApplicationContext 实现了
// Check for listener beans and register them.
// 在所有注册的bean中查找listener bean,注册到消息广播器中
registerListeners();
// Instantiate all remaining (non-lazy-init) singletons.
// 初始化剩下的单实例（非懒加载的）
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.
// 完成刷新过程，通知生命周期处理器lifecycleProcessor刷新过程，同时发出ContextRefreshEvent通知别人
finishRefresh();
}
catch (BeansException ex) {
if (logger.isWarnEnabled()) {
logger.warn("Exception encountered during context initialization - " +
"cancelling refresh attempt: " + ex);
}
// Destroy already created singletons to avoid dangling resources.
// 为防止bean资源占用，在异常处理中，销毁已经在前面过程中生成的单件bean
destroyBeans();
// Reset 'active' flag.
// 重置active标志
cancelRefresh(ex);
// Propagate exception to caller.
throw ex;
}
finally {
// Reset common introspection caches in Spring's core, since we
// might not ever need metadata for singleton beans anymore...
resetCommonCaches();
}
}
}
refresh方法调用finishRefresh();
完成刷新过程，通知生命周期处理器lifecycleProcessor刷新过程，同时发出ContextRefreshEvent通知别人
protected void finishRefresh() {
// Clear context-level resource caches (such as ASM metadata from scanning).
// 清除上下文级别的资源缓存(如扫描的ASM元数据)
// 清空在资源加载器中的所有资源缓存
clearResourceCaches();
// Initialize lifecycle processor for this context.
// 为这个上下文初始化生命周期处理器
// 初始化LifecycleProcessor.如果上下文中找到'lifecycleProcessor'的LifecycleProcessor Bean对象，
// 则使用DefaultLifecycleProcessor
initLifecycleProcessor();
// Propagate refresh to lifecycle processor first.
// 首先将刷新传播到生命周期处理器
// 上下文刷新的通知，例如自动启动的组件
getLifecycleProcessor().onRefresh();
// Publish the final event.
// 发布最终事件
// 新建ContextRefreshedEvent事件对象，将其发布到所有监听器。
publishEvent(new ContextRefreshedEvent(this));
// Participate in LiveBeansView MBean, if active.
// 参与LiveBeansView MBean，如果是活动的
// LiveBeansView:Sping用于支持JMX 服务的类
// 注册当前上下文到LiveBeansView，以支持JMX服务
LiveBeansView.registerApplicationContext(this);
}
initStrategies是初始化springMVC内置组件的方法，先贴出调用的方法轨迹:
publishEvent发布最终事件开始，一直到调用initStrategies，都是监听器相关
initStrategies:523, DispatcherServlet (org.springframework.web.servlet)
onRefresh:514, DispatcherServlet (org.springframework.web.servlet)
onApplicationEvent:901, FrameworkServlet (org.springframework.web.servlet)
onApplicationEvent:1277, FrameworkServlet$ContextRefreshListener (org.springframework.web.servlet)
onApplicationEvent:1273, FrameworkServlet$ContextRefreshListener (org.springframework.web.servlet)
onApplicationEvent:64, GenericApplicationListenerAdapter (org.springframework.context.event)
onApplicationEventInternal:109, SourceFilteringListener (org.springframework.context.event)
onApplicationEvent:73, SourceFilteringListener (org.springframework.context.event)
doInvokeListener:215, SimpleApplicationEventMulticaster (org.springframework.context.event)
invokeListener:202, SimpleApplicationEventMulticaster (org.springframework.context.event)
multicastEvent:164, SimpleApplicationEventMulticaster (org.springframework.context.event)
publishEvent:440, AbstractApplicationContext (org.springframework.context.support)
publishEvent:379, AbstractApplicationContext (org.springframework.context.support)
finishRefresh:1053, AbstractApplicationContext (org.springframework.context.support)
refresh:618, AbstractApplicationContext (org.springframework.context.support)
configureAndRefreshWebApplicationContext:759, FrameworkServlet (org.springframework.web.servlet)
createWebApplicationContext:715, FrameworkServlet (org.springframework.web.servlet)
createWebApplicationContext:773, FrameworkServlet (org.springframework.web.servlet)
initWebApplicationContext:625, FrameworkServlet (org.springframework.web.servlet)
initServletBean:536, FrameworkServlet (org.springframework.web.servlet)
init:185, HttpServletBean (org.springframework.web.servlet)
init:158, GenericServlet (javax.servlet)
initServlet:1164, StandardWrapper (org.apache.catalina.core)
loadServlet:1117, StandardWrapper (org.apache.catalina.core)
load:1010, StandardWrapper (org.apache.catalina.core)
loadOnStartup:4957, StandardContext (org.apache.catalina.core)
startInternal:5264, StandardContext (org.apache.catalina.core)
start:183, LifecycleBase (org.apache.catalina.util)
addChildInternal:726, ContainerBase (org.apache.catalina.core)
addChild:698, ContainerBase (org.apache.catalina.core)
addChild:696, StandardHost (org.apache.catalina.core)
manageApp:1783, HostConfig (org.apache.catalina.startup)
invoke0:-1, NativeMethodAccessorImpl (sun.reflect)
invoke:62, NativeMethodAccessorImpl (sun.reflect)
invoke:43, DelegatingMethodAccessorImpl (sun.reflect)
invoke:498, Method (java.lang.reflect)
invoke:293, BaseModelMBean (org.apache.tomcat.util.modeler)
invoke:819, DefaultMBeanServerInterceptor (com.sun.jmx.interceptor)
invoke:801, JmxMBeanServer (com.sun.jmx.mbeanserver)
createStandardContext:460, MBeanFactory (org.apache.catalina.mbeans)
createStandardContext:408, MBeanFactory (org.apache.catalina.mbeans)
invoke0:-1, NativeMethodAccessorImpl (sun.reflect)
invoke:62, NativeMethodAccessorImpl (sun.reflect)
invoke:43, DelegatingMethodAccessorImpl (sun.reflect)
invoke:498, Method (java.lang.reflect)
invoke:293, BaseModelMBean (org.apache.tomcat.util.modeler)
invoke:819, DefaultMBeanServerInterceptor (com.sun.jmx.interceptor)
invoke:801, JmxMBeanServer (com.sun.jmx.mbeanserver)
invoke:468, MBeanServerAccessController (com.sun.jmx.remote.security)
doOperation:1468, RMIConnectionImpl (javax.management.remote.rmi)
access$300:76, RMIConnectionImpl (javax.management.remote.rmi)
run:1309, RMIConnectionImpl$PrivilegedOperation (javax.management.remote.rmi)
doPrivileged:-1, AccessController (java.security)
doPrivilegedOperation:1408, RMIConnectionImpl (javax.management.remote.rmi)
invoke:829, RMIConnectionImpl (javax.management.remote.rmi)
invoke0:-1, NativeMethodAccessorImpl (sun.reflect)
invoke:62, NativeMethodAccessorImpl (sun.reflect)
invoke:43, DelegatingMethodAccessorImpl (sun.reflect)
invoke:498, Method (java.lang.reflect)
dispatch:346, UnicastServerRef (sun.rmi.server)
run:200, Transport$1 (sun.rmi.transport)
run:197, Transport$1 (sun.rmi.transport)
doPrivileged:-1, AccessController (java.security)
serviceCall:196, Transport (sun.rmi.transport)
handleMessages:568, TCPTransport (sun.rmi.transport.tcp)
run0:826, TCPTransport$ConnectionHandler (sun.rmi.transport.tcp)
lambda$run$0:683, TCPTransport$ConnectionHandler (sun.rmi.transport.tcp)
run:-1, 1102395047 (sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$$Lambda$25)
doPrivileged:-1, AccessController (java.security)
run:682, TCPTransport$ConnectionHandler (sun.rmi.transport.tcp)
runWorker:1142, ThreadPoolExecutor (java.util.concurrent)
run:617, ThreadPoolExecutor$Worker (java.util.concurrent)
run:748, Thread (java.lang)
三、SpringMVC 9大内置组件开始进行初始化
initStrategies初始化
/**初始化
* Initialize the strategy objects that this servlet uses.
* <p>May be overridden in subclasses in order to initialize further strategy objects.
*/
protected void initStrategies(ApplicationContext context) {
// 初始化 MultipartResolver:主要用来处理文件上传.如果定义过当前类型的bean对象，那么直接获取，如果没有的话，可以为null
initMultipartResolver(context);
// 初始化 LocaleResolver:主要用来处理国际化配置,基于URL参数的配置(AcceptHeaderLocaleResolver)，基于session的配置(SessionLocaleResolver)，基于cookie的配置(CookieLocaleResolver)
initLocaleResolver(context);
// 初始化 ThemeResolver:主要用来设置主题Theme
initThemeResolver(context);
// 初始化 HandlerMapping:映射器，用来将对应的request跟controller进行对应
initHandlerMappings(context);
// 初始化 HandlerAdapter:处理适配器，主要包含Http请求处理器适配器，简单控制器处理器适配器，注解方法处理器适配器
initHandlerAdapters(context);
// 初始化 HandlerExceptionResolver:基于HandlerExceptionResolver接口的异常处理
initHandlerExceptionResolvers(context);
// 初始化 RequestToViewNameTranslator:当controller处理器方法没有返回一个View对象或逻辑视图名称，并且在该方法中没有直接往response的输出流里面写数据的时候，spring将会采用约定好的方式提供一个逻辑视图名称
initRequestToViewNameTranslator(context);
// 初始化 ViewResolver: 将ModelAndView选择合适的视图进行渲染的处理器
initViewResolvers(context);
// 初始化 FlashMapManager: 提供请求存储属性，可供其他请求使用
initFlashMapManager(context);
}
1.初始化 MultipartResolver:主要用来处理文件上传
初始化 MultipartResolver:主要用来处理文件上传.如果定义过当前类型的bean对象，那么直接获取，如果没有的话，可以为null
initMultipartResolver(context);
/**
* Initialize the MultipartResolver used by this class. 初始化该类使用的MultipartResolver。
* <p>If no bean is defined with the given name in the BeanFactory for this namespace, 如果在BeanFactory中没有为这个名称空间定义带有给定名称的bean，
* no multipart handling is provided. 不提供多部分处理。
*/
private void initMultipartResolver(ApplicationContext context) {
try {
// 从spring上下文获取名称为 multipartResolver ，类型为MultipartResolver的Bean 实现multipartResolver接口 可以自己定义上传文件组件 本web.xml文件没有自定义 所以此处获取不到的
this.multipartResolver = context.getBean(MULTIPART_RESOLVER_BEAN_NAME, MultipartResolver.class);//multipartResolver
if (logger.isTraceEnabled()) {
logger.trace("Detected " + this.multipartResolver);
}
else if (logger.isDebugEnabled()) {
logger.debug("Detected " + this.multipartResolver.getClass().getSimpleName());
}
}
catch (NoSuchBeanDefinitionException ex) {
// Default is no multipart resolver.
this.multipartResolver = null;
if (logger.isTraceEnabled()) {
logger.trace("No MultipartResolver '" + MULTIPART_RESOLVER_BEAN_NAME + "' declared");
}
}
}
2.初始化 LocaleResolver:主要用来处理国际化配置
初始化 LocaleResolver:主要用来处理国际化配置,基于URL参数的配置(AcceptHeaderLocaleResolver)，基于session的配置(SessionLocaleResolver)，基于cookie的配置(CookieLocaleResolver)
initLocaleResolver(context);
private void initLocaleResolver(ApplicationContext context) {
try {
// 从上下文中获取Bean名称为 LocaleResolver的对象
this.localeResolver = context.getBean(LOCALE_RESOLVER_BEAN_NAME, LocaleResolver.class);//localeResolver 进行国际化相关处理
if (logger.isTraceEnabled()) {
logger.trace("Detected " + this.localeResolver);
}
else if (logger.isDebugEnabled()) {
logger.debug("Detected " + this.localeResolver.getClass().getSimpleName());
}
}
catch (NoSuchBeanDefinitionException ex) {
// We need to use the default.
// 从配置文件中获取默认的AcceptHeaderLocaleResolver对象
this.localeResolver = getDefaultStrategy(context, LocaleResolver.class);
if (logger.isTraceEnabled()) {
logger.trace("No LocaleResolver '" + LOCALE_RESOLVER_BEAN_NAME +
"': using default [" + this.localeResolver.getClass().getSimpleName() + "]");
}
}
}
protected <T> T getDefaultStrategy(ApplicationContext context, Class<T> strategyInterface) {
List<T> strategies = getDefaultStrategies(context, strategyInterface);
if (strategies.size() != 1) {
throw new BeanInitializationException(
"DispatcherServlet needs exactly 1 strategy for interface [" + strategyInterface.getName() + "]");
}
return strategies.get(0);
}
/**
* Create a List of default strategy objects for the given strategy interface.
* <p>The default implementation uses the "DispatcherServlet_test.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) {
// 获得strategyInterface对应的value值
String key = strategyInterface.getName();
// 创建value对应的对象们，并返回
String value = defaultStrategies.getProperty(key);
if (value != null) {
// 基于","分隔，创建classNames数组
String[] classNames = StringUtils.commaDelimitedListToStringArray(value);
// 创建strategyInterface集合
List<T> strategies = new ArrayList<>(classNames.length);
// 遍历classNames数组，创建对应的类，添加到strategyInterface中
for (String className : classNames) {
try {
// 获得className类
Class<?> clazz = ClassUtils.forName(className, DispatcherServlet.class.getClassLoader());
// 创建className对应的类，并添加到strategies中
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(
"Unresolvable class definition for DispatcherServlet's default strategy class [" +
className + "] for interface [" + key + "]", err);
}
}
return strategies;
}
else {
return new LinkedList<>();
}
}
defaultStrategies的初始化是在:这个静态代码块
DEFAULT_STRATEGIES_PATH类路径资源的名称(相对于DispatcherServlet类)，它定义了DispatcherServlet的默认策略名称。
private static final String DEFAULT_STRATEGIES_PATH = “DispatcherServlet_test.properties”;
DispatcherServlet_test.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.method.annotation.RequestMappingHandlerMapping,\
org.springframework.web.servlet.function.support.RouterFunctionMapping
org.springframework.web.servlet.HandlerAdapter=org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter,\
org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter,\
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter,\
org.springframework.web.servlet.function.support.HandlerFunctionAdapter
org.springframework.web.servlet.HandlerExceptionResolver=org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver,\
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
3.初始化 ThemeResolver:主要用来设置主题Theme
// 初始化 ThemeResolver:主要用来设置主题Theme
initThemeResolver(context);
/**
* 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.isTraceEnabled()) {
logger.trace("Detected " + this.themeResolver);
}
else if (logger.isDebugEnabled()) {
logger.debug("Detected " + this.themeResolver.getClass().getSimpleName());
}
}
catch (NoSuchBeanDefinitionException ex) {
// We need to use the default.
// 从配置文件中获取默认的FixedThemeResolver
this.themeResolver = getDefaultStrategy(context, ThemeResolver.class);
if (logger.isTraceEnabled()) {
logger.trace("No ThemeResolver '" + THEME_RESOLVER_BEAN_NAME +
"': using default [" + this.themeResolver.getClass().getSimpleName() + "]");
}
}
}
4.初始化 HandlerMapping:映射器，用来将对应的request跟controller进行对应
// 初始化 HandlerMapping:映射器，用来将对应的request跟controller进行对应
initHandlerMappings(context);
/**初始化该类使用的HandlerMappings。<p>如果没有在BeanFactory中为这个命名空间定义HandlerMapping bean，我们默认为BeanNameUrlHandlerMapping。
* 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) {
// 将handlerMappings置空
this.handlerMappings = null;
// 如果开启探测功能，则扫描已注册的HandlerMapping的bean，添加到handlerMappings中
if (this.detectAllHandlerMappings) {
// Find all HandlerMappings in the ApplicationContext, including ancestor contexts.
// 扫描已注册的handlerMapping的bean
Map<String, HandlerMapping> matchingBeans =
BeanFactoryUtils.beansOfTypeIncludingAncestors(context, HandlerMapping.class, true, false);
// 添加到handlerMappings中，并进行排序
if (!matchingBeans.isEmpty()) {
this.handlerMappings = new ArrayList<>(matchingBeans.values());
// We keep HandlerMappings in sorted order.
AnnotationAwareOrderComparator.sort(this.handlerMappings);
}
}
// 如果关闭探测功能，则获取Bean名称为handlerMapping对应的bean，将其添加到handlerMappings
else {
try {
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.
// 如果未获得到，则获得默认配置的handlerMapping类
if (this.handlerMappings == null) {
this.handlerMappings = getDefaultStrategies(context, HandlerMapping.class);
if (logger.isTraceEnabled()) {
logger.trace("No HandlerMappings declared for servlet '" + getServletName() +
"': using default strategies from DispatcherServlet_test.properties");
}
}
}
默认配置的handlerMapping
5.初始化 HandlerAdapter:处理适配器
初始化 HandlerAdapter:处理适配器，主要包含Http请求处理器适配器，简单控制器处理器适配器，注解方法处理器适配器
initHandlerAdapters(context);
/**
* 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<>(matchingBeans.values());
// We keep HandlerAdapters in sorted order.
AnnotationAwareOrderComparator.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.
// 如果未获得到，则获得默认配置的HandlerAdapter类，HttpRequestHandlerAdapter,SimpleControllerHandlerAdapter,RequestMappingHandlerAdapter
if (this.handlerAdapters == null) {
this.handlerAdapters = getDefaultStrategies(context, HandlerAdapter.class);
if (logger.isTraceEnabled()) {
logger.trace("No HandlerAdapters declared for servlet '" + getServletName() +
"': using default strategies from DispatcherServlet_test.properties");
}
}
默认配置的HandlerAdapter类，
6.初始化 HandlerExceptionResolver
初始化 HandlerExceptionResolver:基于HandlerExceptionResolver接口的异常处理
initHandlerExceptionResolvers(context);
/**
* 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) {
// 置空 handlerExceptionResolver 处理
this.handlerExceptionResolvers = null;
// 自动扫描handlerExceptionResolver类型的bean
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<>(matchingBeans.values());
// We keep HandlerExceptionResolvers in sorted order.
AnnotationAwareOrderComparator.sort(this.handlerExceptionResolvers);
}
}
// 获取名字为HANDLER_EXCEPTION_RESOLVER_BEAN_NAME的bean
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.
// 如果未获得到，则获取默认配置的handlerExceptionResolver类，ExceptionHandlerExceptionResolver,ResponseStatusExceptionResolver,DefaultHandlerExceptionResolver
if (this.handlerExceptionResolvers == null) {
this.handlerExceptionResolvers = getDefaultStrategies(context, HandlerExceptionResolver.class);
if (logger.isTraceEnabled()) {
logger.trace("No HandlerExceptionResolvers declared in servlet '" + getServletName() +
"': using default strategies from DispatcherServlet_test.properties");
}
}
}
7.初始化 RequestToViewNameTranslator
初始化 RequestToViewNameTranslator:当controller处理器方法没有返回一个View对象或逻辑视图名称，并且在该方法中没有直接往response的输出流里面写数据的时候，spring将会采用约定好的方式提供一个逻辑视图名称
initRequestToViewNameTranslator(context);
/**
* 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.isTraceEnabled()) {
logger.trace("Detected " + this.viewNameTranslator.getClass().getSimpleName());
}
else if (logger.isDebugEnabled()) {
logger.debug("Detected " + this.viewNameTranslator);
}
}
catch (NoSuchBeanDefinitionException ex) {
// We need to use the default.
// 如果未找到，则获取默认的 RequestToViewNameTranslator 对象，DefaultRequestToViewNameTranslator
this.viewNameTranslator = getDefaultStrategy(context, RequestToViewNameTranslator.class);
if (logger.isTraceEnabled()) {
logger.trace("No RequestToViewNameTranslator '" + REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME +
"': using default [" + this.viewNameTranslator.getClass().getSimpleName() + "]");
}
}
}
8.初始化 ViewResolver
初始化 ViewResolver: 将ModelAndView选择合适的视图进行渲染的处理器
initViewResolvers(context);
/**
* 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) {
// 置空 viewResolvers 处理
this.viewResolvers = null;
/// 自动扫描 ViewResolver 类型的 Bean
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<>(matchingBeans.values());
// We keep ViewResolvers in sorted order.
AnnotationAwareOrderComparator.sort(this.viewResolvers);
}
}
// 获得名字为VIEW_RESOLVER_BEAN_NAME的bean
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.
// 如果未获得到，则获取默认配置的ViewResolver对象
if (this.viewResolvers == null) {
this.viewResolvers = getDefaultStrategies(context, ViewResolver.class);
if (logger.isTraceEnabled()) {
logger.trace("No ViewResolvers declared for servlet '" + getServletName() +
"': using default strategies from DispatcherServlet_test.properties");
}
}
}
9.初始化 FlashMapManager
初始化 FlashMapManager: 提供请求存储属性，可供其他请求使用
initFlashMapManager(context);
/**
* Initialize the {@link FlashMapManager} used by this servlet instance.
* <p>If no implementation is configured then we default to
* {@code org.springframework.web.servlet.support.DefaultFlashMapManager}.
*/
private void initFlashMapManager(ApplicationContext context) {
try {
this.flashMapManager = context.getBean(FLASH_MAP_MANAGER_BEAN_NAME, FlashMapManager.class);
if (logger.isTraceEnabled()) {
logger.trace("Detected " + this.flashMapManager.getClass().getSimpleName());
}
else if (logger.isDebugEnabled()) {
logger.debug("Detected " + this.flashMapManager);
}
}
catch (NoSuchBeanDefinitionException ex) {
// We need to use the default.
// 未找到，则获取默认的 FlashMapManager 对象，SessionFlashMapManager
this.flashMapManager = getDefaultStrategy(context, FlashMapManager.class);
if (logger.isTraceEnabled()) {
logger.trace("No FlashMapManager '" + FLASH_MAP_MANAGER_BEAN_NAME +
"': using default [" + this.flashMapManager.getClass().getSimpleName() + "]");
}
}
}
SpringMVC框架中Spring父容器和SpringMVC子容器加载的流程以及SpringMVC九大内置组件的初始已经完成接下来开始进行发送请求相关的源码。
