springmvc源码解析之配置加载SpringServletContainerI...

用SpringMVC源码解析之配置加载SpringServletContainerInitializer

用SpringMVC配置解析

sdervlet容器启动的时候会加载org.springframework.web.SpringServletContainerInitializer这个类，调用初始化类的onStartup方法

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@Override public void onStartup(Set<Class<?>> webAppInitializerClasses, ServletContext servletContext) throws ServletException {   List<WebApplicationInitializer> initializers = new LinkedList<WebApplicationInitializer>(); if (webAppInitializerClasses != null) { for (Class<?> waiClass : webAppInitializerClasses) { // Be defensive: Some servlet containers provide us with invalid classes, // no matter what @HandlesTypes says... if (!waiClass.isInterface() && !Modifier.isAbstract(waiClass.getModifiers()) && WebApplicationInitializer.class.isAssignableFrom(waiClass)) { try { initializers.add((WebApplicationInitializer) waiClass.newInstance()); } catch（Throwable ex）{ throw new ServletException（“无法实例化WebApplicationInitializer类”，ex）; } } } }   如果（initializers.isEmpty（））{ servletContext.log（ “检测到的无弹簧WebApplicationInitializer类型上的类路径”）; 返回; }   servletContext.log（initializers.size（）+ “类路径上检测到的弹簧WebApplicationInitializers”）; AnnotationAwareOrderComparator.sort（初始化）; for（WebApplicationInitializer initializer：initializers）{ initializer.onStartup（servletContext）; } / [mw_shl_code] [color=#000][font=sans-serif][size=16px]进入到DispatcherServlet初始化器org.springframework.web.servlet.support.AbstractDispatcherServletInitializer＃onStartup这个方法[/size][/font][/color] [mw_shl_code=applescript,true] @Override public void onStartup(ServletContext servletContext) throws ServletException { //调用上下文加载器初始化类的onStartup方法 super.onStartup(servletContext); //注册DispatcherServlet registerDispatcherServlet(servletContext); }

进入到这个方法org.springframework.web.context.AbstractContextLoaderInitializer#onStartup，执行ContextLoader初始化器

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@Override public void onStartup(ServletContext servletContext) throws ServletException { registerContextLoaderListener(servletContext); }

进入到这个方法org.springframework.web.context.AbstractContextLoaderInitializer#registerContextLoaderListener，注册ContextLoader监听器
[mw_shl_code = applescript，true] protected void registerContextLoaderListener（ServletContext servletContext）{ 
//获取上层应用上下文对象 - > 
WebApplicationContext rootAppContext = createRootApplicationContext（）; 
if（rootAppContext！= null）{ 
//创建上下文加载监听器
ContextLoaderListener listener = new ContextLoaderListener（rootAppContext）; 
listener.setContextInitializers（getRootApplicationContextInitializers（））; 
//把上下文加载监听器加载到servlet容器
servletContext.addListener（listener）; 
} 
else { 
logger.debug（“没有注册ContextLoaderListener，因为”+ 
“createRootApplicationContext（）没有返回应用程序上下文”）; 
} 
} [/ mw_shl_code]
进入到这个方法org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer#createRootApplicationContext

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@Override protected WebApplicationContext createRootApplicationContext() { //从子类实现中或者从@Configuration、@Component注解配置中获取配置类 Class<?>[] configClasses = getRootConfigClasses(); if (!ObjectUtils.isEmpty(configClasses)) { // 如果没有配置就默认初始化基于注解的web应用上下文类 AnnotationConfigWebApplicationContext rootAppContext = new AnnotationConfigWebApplicationContext(); rootAppContext.register(configClasses); return rootAppContext; } else { return null; } }

进入到这个方法org.springframework.web.context.AbstractContextLoaderInitializer#getRootApplicationContextInitializers

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protected ApplicationContextInitializer<?>[] getRootApplicationContextInitializers() { return null; }

返回到这个方法org.springframework.web.servlet.support.AbstractDispatcherServletInitializer#onStartup这一行

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1 2	// 注册DispatcherServlet registerDispatcherServlet(servletContext);

进入到这个方法org.springframework.web.servlet.support.AbstractDispatcherServletInitializer#registerDispatcherServlet

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protected void registerDispatcherServlet(ServletContext servletContext) { //获取servletName，默认名称是dispatcher String servletName = getServletName（）; Assert.hasLength（servletName，“getServletName（）不能返回空或null”）; //创建servlet程序上下文 - > WebApplicationContext servletAppContext = createServletApplicationContext（）; Assert.notNull（servletAppContext， “createServletApplicationContext（）没有返回 servlet [”+ servletName +“]”）的应用程序“+ ”上下文; //创建DispatcherServlet FrameworkServlet dispatcherServlet = createDispatcherServlet（servletAppContext）; //注册的servlet上下文初始化器，这里是模板实现 dispatcherServlet.setContextInitializers（getServletApplicationContextInitializers（））; //添加的DispatcherServlet到的servlet容器 ServletRegistration.Dynamic registration = servletContext.addServlet（servletName，dispatcherServlet）; Assert.notNull（注册， “无法注册名称为'的servlet +”+ servletName +“'。”+ “检查是否有另一个以相同名称注册的servlet。”）; registration.setLoadOnStartup（1）; //获取servletMapping实现，这里是抽象实现，注册映射 registration.addMapping（getServletMappings（））; //设置是否支持异步，默认支持 registration.setAsyncSupported（isAsyncSupported（））; //获取servletFilter，这里是模板实现 Filter [] filters = getServletFilters（）; if（！ObjectUtils.isEmpty（filters））{ for（Filter filter：filters）{ //注册过滤器 - > registerServletFilter（servletContext，filter）;       //定制化注册，默认是模板实现 customizeRegistration(registration); }

进入到这个方法org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer#createServletApplicationContext

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@Override protected WebApplicationContext createServletApplicationContext() { //创建基于注解的web应用上下文 AnnotationConfigWebApplicationContext servletAppContext = new AnnotationConfigWebApplicationContext(); //从子类实现中或者从@Configuration、@Component注解配置中获取配置类 Class<?>[] configClasses = getServletConfigClasses(); if (!ObjectUtils.isEmpty(configClasses)) { // 注册@Configuration配置的配置加载类到AnnotationConfigWebApplicationContext servletAppContext.register(configClasses); } return servletAppContext; }

进入到这个方法org.springframework.web.servlet.support.AbstractDispatcherServletInitializer#registerServletFilter
[mw_shl_code=applescript,true]protected FilterRegistration.Dynamic registerServletFilter(ServletContext servletContext, Filter filter) {
//获取filteName
String filterName = Conventions.getVariableName(filter);
//添加filter到servlet容器
Dynamic registration = servletContext.addFilter(filterName, filter);
//如果filter注册失败
if (registration == null) {
int counter = -1;
while (counter == -1 || registration == null) {
counter++;
//添加filter#0 到servlet容器
registration = servletContext.addFilter(filterName + "#" + counter, filter);
//提示有同样的名字的过滤器已注册过
Assert.isTrue（计数器<100，
“无法注册过滤器'”+过滤器+“'。”+ 
“可能已经注册了相同的过滤器实例吗？”）; 
} 
} 
//是否支持异步，默认是
registration.setAsyncSupported（isAsyncSupported（））; 
registration.addMappingForServletNames（getDispatcherTypes（），false，getServletName（））; 
退货登记; 
} [/ mw_shl_code]

回退到这个方法org.springframework.web.SpringServletContainerInitializer＃onStartup

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