第一節 參考
一.參考
<從零開始寫javaweb框架>
<Spring源碼深度解析>
https://blog.csdn.net/u010723709/article/details/47185959
https://blog.csdn.net/array_dear/article/details/87399976
二.編譯
https://github.com/spring-projects/spring-framework下載源碼
按照gradle,進入對應模塊,執行gradle clean build -x test.
注意看import-into-idea.md文件.先執行gradlew :spring-oxm:compileTestJava.再執行gradlew idea -x test.
第二節 架構
一.主要模塊
核心爲IoC依賴注入和AOP面向切面的功能，在此基礎上，實現了webmvc,spring-tx事務,spring-jdbc數據庫連接,spring-jms消息,spring-expression表達式解析等功能.
1.spring-core
包含IoC的部分功能，io操作,序列化,util,cglib等的一些工具包.
2.spring-beans
主要實現IOC功能,包含BeansFactory,單例，註解支持,bean的xml解析等.
3.spring-context
主要實現spring的容器加載,容器擴展功能,核心爲ApplicationContext接口.支持spring容器通過xml或者掃描註解加載,國際化，事務傳播等。也支持通過第三方模塊的調用，比如緩存，郵件，調度,模板引擎等.
4.spring-expression
主要實現對容器中bean對象的檢索功能
5.spring-jdbc
提供對數據庫，jdbc的方便調用
6.spring-orm
提供對jpa，hibernate的集成調用.
7.spring-oxm
提供object對象和xml文件的轉換功能
8.spring-jms
提供生產者和消費者的異步消息模型的調用.
9.spring-tx
支持編程式和聲明式事務管理功能.
10.spring-web
實現spring的http協議解析功能,比如http的header和body的解析，編解碼，序列化,文件上傳.
11.spring-webmvc
實現spring的servlet功能.核心類爲DispatcherServlet.包含web請求的解析，返回視圖解析等.
12.spring-websocket
支持websocket功能
13.spring-aop
面向切面AOP的功能
14.spring-aspects
集成AspectJ框架,實現aspect註解功能.
第三節 源碼細節
一.Refresh入口
IOC核心是AbstractApplicationContext.refresh()方法.測試用例入口GenericXmlApplicationContextTests.classRelativeResourceLoading_load()方法.普通的spring mvc的工程入口是spring-webmvc模塊的FrameworkServlet.initServletBean()方法創建WebApplicationContext,即XmlWebApplicationContext,調用WebApplicationContext.refresh()方法.
refresh()方法代碼如下:
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// Prepare this context for refreshing.
prepareRefresh();
// Tell the subclass to refresh the internal bean factory.
/*
加載spring的xml文件.
1.在AbstractXmlApplicationContext#loadBeanDefinitions()方法中調用getDefaultConfigLocations()找到spring的xml文件路徑.
2.調用AbstractBeanDefinitionReader.loadBeanDefinitions()->XmlBeanDefinitionReader#loadBeanDefinitions()調用jax庫加載xml文件,解析成Document格式.註冊到DefaultListableBeanFactory#beanDefinitionMap中.
3.創建一個DefaultListableBeanFactory對象返回.
*/
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// Prepare the bean factory for use in this context.
//註冊一些BeanPostProcessor,比如ApplicationContextAwareProcessor.
prepareBeanFactory(beanFactory);
try {
// Allows post-processing of the bean factory in context subclasses.
postProcessBeanFactory(beanFactory);
// Invoke factory processors registered as beans in the context.
/* 註冊一些xml文件中配置的BeanFactoryPostProcessor.BeanDefinitionRegistryPostProcessor是對前者的補充繼承.比如ConfigurationClassPostProcessor(對註解bean的處理),PropertyPlaceholderConfigurer.註冊完後直接調用invokeBeanDefinitionRegistryPostProcessors()方法回調每一個BeanFactoryPostProcessor實現類的postProcessBeanDefinitionRegistry()方法。比如調用ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry()實現對註解bean的註冊.
在invokeBeanFactoryPostProcessors()方法中繼續調用invokeBeanFactoryPostProcessors,回調BeanFactoryPostProcessor類的postProcessBeanFactory()方法.比如ConfigurationClassPostProcessor.postProcessBeanFactory()方法.在這個方法中添加ImportAwareBeanPostProcessor.
BeanFactoryPostProcessor在這裏調用執行,BeanPostProcessor在bean創建時執行，這裏就是區別
*/
invokeBeanFactoryPostProcessors(beanFactory);
// Register bean processors that intercept bean creation.
/* 註冊xml文件中配置的BeanPostProcessor.註冊BeanPostProcessor,在後面調用getBean()方法,bean實例化時回調postProcessBeforeInitialization()和postProcessAfterInitialization.
BeanPostProcessor類的實例，比如AutowiredAnnotationBeanPostProcessor(處理autowire註解),RequiredAnnotationBeanPostProcessor,CommonAnnotationBeanPostProcessor(處理Resource註解). */
registerBeanPostProcessors(beanFactory);
// Initialize message source for this context.
//默認添加DelegatingMessageSource()處理語言的國際化.國際化後面新開貼分析。
initMessageSource();
// Initialize event multicaster for this context.
//默認添加SimpleApplicationEventMulticaster類作爲事件廣播器.事件廣播器後面新開貼介紹.
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
//默認是空實現，交給子類處理
onRefresh();
// Check for listener beans and register them.
//註冊實現了ApplicationListener接口的類到AbstractApplicationEventMulticaster#defaultRetriever裏面,默認是空的
registerListeners();
// Instantiate all remaining (non-lazy-init) singletons.
/*
對於非延遲加載的bean，實例化對象並初始化成員.進入DefaultListableBeanFactory.preInstantiateSingletons(),調用getBean,初始化bean.比如xxxController,xxxService,aop代理類,internalConfigurationAnnotationProcessor,internalAutowiredAnnotationProcessor,internalRequiredAnnotationProcessor,internalCommonAnnotationProcessor,internalEventListenerProcessor,propertyConfigurer等
*/
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.
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.
destroyBeans();
// Reset 'active' flag.
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();
}
}
}
二.obtainFreshBeanFactory()加載xml,註冊bean.
核心處理是進入XmlBeanDefinitionReader.doLoadBeanDefinitions()
protected int doLoadBeanDefinitions(InputSource inputSource, Resource resource)
throws BeanDefinitionStoreException {
try {
//調用jax庫加載xml爲Document格式
Document doc = doLoadDocument(inputSource, resource);
//創建DefaultBeanDefinitionDocumentReader
//進入DefaultBeanDefinitionDocumentReader.doRegisterBeanDefinitions()->DefaultBeanDefinitionDocument//Reader#parseBeanDefinitions()->DefaultBeanDefinitionDocumentReader#parseDefaultElement解析標籤,把Document解析到類型爲BeanDefinitionParserDelegate的DefaultBeanDefinitionDocumentReader#delegate裏面.
//返回已經註冊的bean的個數，這裏爲0
return registerBeanDefinitions(doc, resource);
}
...
}
解析標籤
protected void parseBeanDefinitions(Element root, BeanDefinitionParserDelegate delegate) {
if (delegate.isDefaultNamespace(root)) {
NodeList nl = root.getChildNodes();
for (int i = 0; i < nl.getLength(); i++) {
Node node = nl.item(i);
if (node instanceof Element) {
Element ele = (Element) node;
if (delegate.isDefaultNamespace(ele)) {
//解析默認的四個標籤，即import,bean,beans,alias
parseDefaultElement(ele, delegate);
}
else {
//解析自定義標籤，比如context:component,annotation-config
//先進入BeanDefinitionParserDelegate#parseCustomElement()，調用ContextNamespaceHandler#init()註冊常用幾個標籤的處理類.然後調用處理類的NamespaceHandler#parse()方法解析標籤
delegate.parseCustomElement(ele);
}
}
}
}
else {
delegate.parseCustomElement(root);
}
}
自定義標籤處理邏輯BeanDefinitionParserDelegate#parseCustomElement()
public BeanDefinition parseCustomElement(Element ele, BeanDefinition containingBd) {
//獲取標籤的命名空間
String namespaceUri = getNamespaceURI(ele);
//調用下面的ContextNamespaceHandler.init()方法註冊標籤處理類
NamespaceHandler handler = this.readerContext.getNamespaceHandlerResolver().resolve(namespaceUri);
if (handler == null) {
error("Unable to locate Spring NamespaceHandler for XML schema namespace [" + namespaceUri + "]", ele);
return null;
}
//調用標籤的解析方法
return handler.parse(ele, new ParserContext(this.readerContext, this, containingBd));
}
註冊自定義標籤解析類ContextNamespaceHandler.init(),所謂註冊就是放到beanDefinitionMap,beanDefinitionNames中.默認下面一共註冊了六個.
public void init() {
//用來處理配置文件中的佔位符
registerBeanDefinitionParser("property-placeholder", new PropertyPlaceholderBeanDefinitionParser());
registerBeanDefinitionParser("property-override", new PropertyOverrideBeanDefinitionParser());
/*
註冊第一個ConfigurationClassPostProcessor(實現了BeanFactoryPostProcessor接口),第二個AutowiredAnnotationBeanPostProcessor,
第三個RequiredAnnotationBeanPostProcessor，第四個CommonAnnotationBeanPostProcessor(這幾個都實現了BeanPostProcessor接口)，第五個EventListenerMethodProcessor(實現了ApplicationContextAware接口)，第六個DefaultEventListenerFactory
*/
registerBeanDefinitionParser("annotation-config", new AnnotationConfigBeanDefinitionParser());
//掃描目錄，標記有@Component註解,@Service,@Controller,@Repository都有這個註解
registerBeanDefinitionParser("component-scan", new ComponentScanBeanDefinitionParser());
registerBeanDefinitionParser("load-time-weaver", new LoadTimeWeaverBeanDefinitionParser());
registerBeanDefinitionParser("spring-configured", new SpringConfiguredBeanDefinitionParser());
registerBeanDefinitionParser("mbean-export", new MBeanExportBeanDefinitionParser());
registerBeanDefinitionParser("mbean-server", new MBeanServerBeanDefinitionParser());
}
標籤解析DefaultBeanDefinitionDocumentReader#parseDefaultElement
private void parseDefaultElement(Element ele, BeanDefinitionParserDelegate delegate) {
//解析import標籤
if (delegate.nodeNameEquals(ele, IMPORT_ELEMENT)) {
importBeanDefinitionResource(ele);
}
//解析alias標籤
else if (delegate.nodeNameEquals(ele, ALIAS_ELEMENT)) {
processAliasRegistration(ele);
}
//解析bean標籤
else if (delegate.nodeNameEquals(ele, BEAN_ELEMENT)) {
processBeanDefinition(ele, delegate);
}
//解析beans標籤
else if (delegate.nodeNameEquals(ele, NESTED_BEANS_ELEMENT)) {
// recurse
doRegisterBeanDefinitions(ele);
}
}
解析Bean標籤
protected void processBeanDefinition(Element ele, BeanDefinitionParserDelegate delegate) {
//解析bean標籤的id,name等屬性值到BeanDefinitionHolder的成員變量裏面
BeanDefinitionHolder bdHolder = delegate.parseBeanDefinitionElement(ele);
if (bdHolder != null) {
bdHolder = delegate.decorateBeanDefinitionIfRequired(ele, bdHolder);
try {
// Register the final decorated instance.
//進入DefaultListableBeanFactory#registerBeanDefinition()方法.
BeanDefinitionReaderUtils.registerBeanDefinition(bdHolder, getReaderContext().getRegistry());
}
catch (BeanDefinitionStoreException ex) {
getReaderContext().error("Failed to register bean definition with name '" +
bdHolder.getBeanName() + "'", ele, ex);
}
// Send registration event.
getReaderContext().fireComponentRegistered(new BeanComponentDefinition(bdHolder));
}
}
註冊標籤。註冊到DefaultListableBeanFactory
public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)
throws BeanDefinitionStoreException {
...
BeanDefinition oldBeanDefinition;
oldBeanDefinition = this.beanDefinitionMap.get(beanName);
//已經註冊過的bean,拋異常或者覆蓋
if (oldBeanDefinition != null) {
if (!isAllowBeanDefinitionOverriding()) {
throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName,
"Cannot register bean definition [" + beanDefinition + "] for bean '" + beanName +
"': There is already [" + oldBeanDefinition + "] bound.");
}
...
this.beanDefinitionMap.put(beanName, beanDefinition);
}
else {
//如果已經創建過bean
if (hasBeanCreationStarted()) {
// Cannot modify startup-time collection elements anymore (for stable iteration)
synchronized (this.beanDefinitionMap) {
this.beanDefinitionMap.put(beanName, beanDefinition);
List<String> updatedDefinitions = new ArrayList<String>(this.beanDefinitionNames.size() + 1);
updatedDefinitions.addAll(this.beanDefinitionNames);
updatedDefinitions.add(beanName);
this.beanDefinitionNames = updatedDefinitions;
if (this.manualSingletonNames.contains(beanName)) {
Set<String> updatedSingletons = new LinkedHashSet<String>(this.manualSingletonNames);
updatedSingletons.remove(beanName);
this.manualSingletonNames = updatedSingletons;
}
}
}
else {
//向beanDefinitionMap,beanDefinitionNames中註冊bean
// Still in startup registration phase
this.beanDefinitionMap.put(beanName, beanDefinition);
this.beanDefinitionNames.add(beanName);
this.manualSingletonNames.remove(beanName);
}
this.frozenBeanDefinitionNames = null;
}
if (oldBeanDefinition != null || containsSingleton(beanName)) {
resetBeanDefinition(beanName);
}
}
三.prepareBeanFactory()準備bean工廠的一些參數.bean工廠即DefaultListableBeanFactory
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
// Tell the internal bean factory to use the context's class loader etc.
//設置bean工廠的類加載器,默認是AppClassLoader.
beanFactory.setBeanClassLoader(getClassLoader());
//設置bean標籤的 表達式的解析器
beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
//設置資源文件的註冊
beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));
// Configure the bean factory with context callbacks.
//重要,添加各種xxxAware接口的觀察者
beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
// BeanFactory interface not registered as resolvable type in a plain factory.
// MessageSource registered (and found for autowiring) as a bean.
//註冊BeanFactory的依賴?幹啥用的
beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
beanFactory.registerResolvableDependency(ResourceLoader.class, this);
beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
beanFactory.registerResolvableDependency(ApplicationContext.class, this);
// Detect a LoadTimeWeaver and prepare for weaving, if found.
if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
// Set a temporary ClassLoader for type matching.
beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}
// Register default environment beans.
//向singletonObjects直接添加系統默認的三個bean,讀取配置文件的systemProperties,systemEnvironment,environment
if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) {
beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment());
}
if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) {
beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties());
}
if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) {
beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment());
}
}
四.invokeBeanFactoryPostProcessors
默認傳進來的beanFactoryPostProcessors是空的。springboot是有三個CachingMetadataReaderFactoryPostProcessor,ConfigurationWarningsPostProcessor,PropertySourceOrderingPostProcessor.
public static void invokeBeanFactoryPostProcessors(
ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {
// Invoke BeanDefinitionRegistryPostProcessors first, if any.
Set<String> processedBeans = new HashSet<String>();
if (beanFactory instanceof BeanDefinitionRegistry) {
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
List<BeanFactoryPostProcessor> regularPostProcessors = new LinkedList<BeanFactoryPostProcessor>();
List<BeanDefinitionRegistryPostProcessor> registryPostProcessors =
new LinkedList<BeanDefinitionRegistryPostProcessor>();
for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
BeanDefinitionRegistryPostProcessor registryPostProcessor =
(BeanDefinitionRegistryPostProcessor) postProcessor;
registryPostProcessor.postProcessBeanDefinitionRegistry(registry);
registryPostProcessors.add(registryPostProcessor);
}
else {
regularPostProcessors.add(postProcessor);
}
}
// Do not initialize FactoryBeans here: We need to leave all regular beans
// uninitialized to let the bean factory post-processors apply to them!
// Separate between BeanDefinitionRegistryPostProcessors that implement
// PriorityOrdered, Ordered, and the rest.
/* 從beanDefinitionMap中取出實現了BeanFactoryPostProcessor接口的對象，下面代碼直接去調用
默認是空。如果配置了<context:annotation-config/>.<context:component-scan/>,這裏是ConfigurationClassPostProcessor
*/
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
//調用實現了BeanDefinitionRegistryPostProcessors接口的類,按照順序，先調用PriorityOrdered,再調用Ordered,
//最後調用剩下的
// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
List<BeanDefinitionRegistryPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanDefinitionRegistryPostProcessor>();
//對幾個BeanFactoryPostProcessor接口實現類排個序
for (String ppName : postProcessorNames) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
}
}
sortPostProcessors(beanFactory, priorityOrderedPostProcessors);
registryPostProcessors.addAll(priorityOrderedPostProcessors);
/*
調用ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(),在這裏面註冊ImportAwareBeanPostProcessor處理import註解(比如aop的註解實現@Import(AspectJAutoProxyRegistrar.class))，EnhancedConfigurationBeanPostProcessor
*/
invokeBeanDefinitionRegistryPostProcessors(priorityOrderedPostProcessors, registry);
// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
List<BeanDefinitionRegistryPostProcessor> orderedPostProcessors = new ArrayList<BeanDefinitionRegistryPostProcessor>();
for (String ppName : postProcessorNames) {
if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
}
}
sortPostProcessors(beanFactory, orderedPostProcessors);
registryPostProcessors.addAll(orderedPostProcessors);
//在前面的invokeBeanDefinitionRegistryPostProcessors可能新增了實現類，這裏再調用一次.
//在上面的循環中已經排除了processedBeans裏面已經調用過得實現類,不會重複調用
invokeBeanDefinitionRegistryPostProcessors(orderedPostProcessors, registry);
// Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear.
boolean reiterate = true;
while (reiterate) {
reiterate = false;
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
if (!processedBeans.contains(ppName)) {
BeanDefinitionRegistryPostProcessor pp = beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class);
registryPostProcessors.add(pp);
processedBeans.add(ppName);
pp.postProcessBeanDefinitionRegistry(registry);
reiterate = true;
}
}
}
// Now, invoke the postProcessBeanFactory callback of all processors handled so far.
invokeBeanFactoryPostProcessors(registryPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
}
else {
// Invoke factory processors registered with the context instance.
invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);
}
// Do not initialize FactoryBeans here: We need to leave all regular beans
// uninitialized to let the bean factory post-processors apply to them!
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
//調用實現了BeanFactoryPostProcessors接口的類,按照順序，先調用PriorityOrdered,再調用Ordered,
//最後調用剩下的
// Separate between BeanFactoryPostProcessors that implement PriorityOrdered,
// Ordered, and the rest.
List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();
List<String> orderedPostProcessorNames = new ArrayList<String>();
List<String> nonOrderedPostProcessorNames = new ArrayList<String>();
for (String ppName : postProcessorNames) {
if (processedBeans.contains(ppName)) {
// skip - already processed in first phase above
}
else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessorNames.add(ppName);
}
else {
nonOrderedPostProcessorNames.add(ppName);
}
}
// First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.
sortPostProcessors(beanFactory, priorityOrderedPostProcessors);
invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);
// Next, invoke the BeanFactoryPostProcessors that implement Ordered.
List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();
for (String postProcessorName : orderedPostProcessorNames) {
orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
sortPostProcessors(beanFactory, orderedPostProcessors);
invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);
// Finally, invoke all other BeanFactoryPostProcessors.
List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();
for (String postProcessorName : nonOrderedPostProcessorNames) {
nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);
// Clear cached merged bean definitions since the post-processors might have
// modified the original metadata, e.g. replacing placeholders in values...
beanFactory.clearMetadataCache();
}
五.registerBeanPostProcessors()註冊BeanPostProcessor,在後面bean實例化時回調postProcessBeforeInitialization()和postProcessAfterInitialization
public static void registerBeanPostProcessors(
ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
/* 獲取beanDefinitionMap中實現了BeanPostProcessor接口的實現類
這裏有EnhancedConfigurationBeanPostProcessor,ImportAwareBeanPostProcessor,CommonAnnotationBeanPostProcessor,
RequiredAnnotationBeanPostProcessor,AutowiredAnnotationBeanPostProcessor五個,都是在前面註冊過的.
*/
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);
// Register BeanPostProcessorChecker that logs an info message when
// a bean is created during BeanPostProcessor instantiation, i.e. when
// a bean is not eligible for getting processed by all BeanPostProcessors.
//添加對BeanPostProcessor的檢查類，也做日誌記錄
int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));
// Separate between BeanPostProcessors that implement PriorityOrdered,
// Ordered, and the rest.
//對實現了PriorityOrdered接口的BeanPostProcessor類，單獨存儲，優先處理.
List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanPostProcessor>();
List<BeanPostProcessor> internalPostProcessors = new ArrayList<BeanPostProcessor>();
List<String> orderedPostProcessorNames = new ArrayList<String>();
List<String> nonOrderedPostProcessorNames = new ArrayList<String>();
for (String ppName : postProcessorNames) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
priorityOrderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessorNames.add(ppName);
}
else {
nonOrderedPostProcessorNames.add(ppName);
}
}
// First, register the BeanPostProcessors that implement PriorityOrdered.
sortPostProcessors(beanFactory, priorityOrderedPostProcessors);
//所謂註冊就是,之前只是把這些實現類放到beanDefinitionMap中，現在放到AbstractBeanFactory#beanPostProcessors中，後面調用時//從這個成員裏面取
registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);
// Next, register the BeanPostProcessors that implement Ordered.
List<BeanPostProcessor> orderedPostProcessors = new ArrayList<BeanPostProcessor>();
for (String ppName : orderedPostProcessorNames) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
orderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
sortPostProcessors(beanFactory, orderedPostProcessors);
registerBeanPostProcessors(beanFactory, orderedPostProcessors);
// Now, register all regular BeanPostProcessors.
//註冊不是PriorityOrdered優先的BeanPostProcessor實現類,放到AbstractBeanFactory#beanPostProcessors中.
//這裏默認爲空列表
List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanPostProcessor>();
for (String ppName : nonOrderedPostProcessorNames) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
nonOrderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);
// Finally, re-register all internal BeanPostProcessors.
sortPostProcessors(beanFactory, internalPostProcessors);
registerBeanPostProcessors(beanFactory, internalPostProcessors);
//添加ApplicationListenerDetector作爲BeanPostProcessor,做什麼用?
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}
六.finishBeanFactoryInitialization()實例化bean對象並初始化成員.
進入DefaultListableBeanFactory#preInstantiateSingletons()方法處理.
裏面的getBean()新開貼分析.
public void preInstantiateSingletons() throws BeansException {
// Iterate over a copy to allow for init methods which in turn register new bean definitions.
// While this may not be part of the regular factory bootstrap, it does otherwise work fine.
//取出所有註冊過的bean
List<String> beanNames = new ArrayList<String>(this.beanDefinitionNames);
// Trigger initialization of all non-lazy singleton beans...
/* 遍歷所有的bean，一個個調用getBean()實例化和初始化成員
這裏除了業務bean,加了context:component,annotation-config註解的話,spring自帶有八個bean
*/
for (String beanName : beanNames) {
//這裏是如果通過beanName找不到AbstractBeanFactory#mergedBeanDefinitions中的bean定義,通過父子關係查找,後面新開貼分析
RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);
//如果bean不是抽象類,是單例的類，不是延遲加載的就開始創建過程
if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) {
//如果是FactoryBean,需要處理getObjectType(),getObject()
if (isFactoryBean(beanName)) {
final FactoryBean<?> factory = (FactoryBean<?>) getBean(FACTORY_BEAN_PREFIX + beanName);
boolean isEagerInit;
if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {
isEagerInit = AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
@Override
public Boolean run() {
return ((SmartFactoryBean<?>) factory).isEagerInit();
}
}, getAccessControlContext());
}
else {
isEagerInit = (factory instanceof SmartFactoryBean &&
((SmartFactoryBean<?>) factory).isEagerInit());
}
if (isEagerInit) {
getBean(beanName);
}
}
else {
//不是工廠bean,直接開始創建過程
getBean(beanName);
}
}
}
// Trigger post-initialization callback for all applicable beans...
for (String beanName : beanNames) {
//從singletonObjects獲取所有創建的bean對象
Object singletonInstance = getSingleton(beanName);
//如果bean對象實現了SmartInitializingSingleton接口，調用它的afterSingletonsInstantiated()方法
//EventListenerMethodProcessor實現了這個接口
if (singletonInstance instanceof SmartInitializingSingleton) {
final SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton) singletonInstance;
if (System.getSecurityManager() != null) {
AccessController.doPrivileged(new PrivilegedAction<Object>() {
@Override
public Object run() {
smartSingleton.afterSingletonsInstantiated();
return null;
}
}, getAccessControlContext());
}
else {
smartSingleton.afterSingletonsInstantiated();
}
}
}
}