第二节:spring源码解析之扩展原理BeanFactoryPostProcessor和BeanDefinitionPostProcessor和ApplicationListener
一:Spring是如何发布事件的? ApplicationListener
1.1)自己写一个TulingApplicationListener 实现ApplicationListener接口,并且把该组件加入到容器中.
@Component
public class TulingApplicationListener implements ApplicationListener {
//接受到消息，回调该方法
@Override
public void onApplicationEvent(ApplicationEvent event) {
System.out.println("TulingApplicationListener 接受到了一个事件"+event);
}
}
public static void main(String[] args) {
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(MainConfig.class);
//手动发布一个事件
ctx.publishEvent(new ApplicationEvent("我手动发布了一个事件") {
@Override
public Object getSource() {
return super.getSource();
}
});
//容器关闭也发布事件
ctx.close();
}
测试结果:
TulingApplicationListener 接受到了一个事件org.springframework.context.event.ContextRefreshedEvent[source=org.springframework.context.annotation.AnnotationConfigApplicationContext@37bba400: startup date [Mon May 27 21:42:51 CST 2019]; root of context hierarchy]
TulingApplicationListener 接受到了一个事件com.tuling.testapplicationlistener.MainClass$1[source=我手动发布了一个事件]
TulingApplicationListener 接受到了一个事件org.springframework.context.event.ContextClosedEvent[source=org.springframework.context.annotation.AnnotationConfigApplicationContext@37bba400: startup date [Mon May 27 21:42:51 CST 2019]; root of context hierarchy]
源码解析:
i1>org.springframework.context.support.AbstractApplicationContext#refresh
i2>org.springframework.context.support.AbstractApplicationContext#initApplicationEventMulticaster（初始化事件多播器）
i3>org.springframework.context.support.AbstractApplicationContext#registerListeners（把事件监听器注册到多播器上去）
i2(初始化事件多播器源码解析)
protected void initApplicationEventMulticaster() {
ConfigurableListableBeanFactory beanFactory = getBeanFactory();
/判断IOC容器中包含applicationEventMulticaster 事件多播器的Bean的name
if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
/创建一个applicationEventMulticaster的bean放在IOC 容器中,bean的name 为applicationEventMulticaster
this.applicationEventMulticaster =beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
if (logger.isDebugEnabled()) {
logger.debug("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
}
}
/容器中不包含一个beanName 为applicationEventMulticaster的多播器组件
else {
//创建一个SimpleApplicationEventMulticaster 多播器
this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
//注册到容器中
beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
if (logger.isDebugEnabled()) {
logger.debug("Unable to locate ApplicationEventMulticaster with name '" +
APPLICATION_EVENT_MULTICASTER_BEAN_NAME +
"': using default [" + this.applicationEventMulticaster + "]");
}
}
}
i3：把容器中的监听器注册到多播器上去 源码解析
protected void registerListeners() {
//去容器中把applicationListener 捞取出来注册到多播器上去（系统的）
for (ApplicationListener<?> listener : getApplicationListeners()) {
getApplicationEventMulticaster().addApplicationListener(listener);
}
//我们自己实现了ApplicationListener 的组件
String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);
for (String listenerBeanName : listenerBeanNames) {
getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);
}
//在这里之前，我们早期想发布的事件 由于没有多播器没有发布，在这里我们总算有了自己的多播器，可以在这里发布早期堆积的事件了.
Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;
this.earlyApplicationEvents = null;
if (earlyEventsToProcess != null) {
for (ApplicationEvent earlyEvent : earlyEventsToProcess) {
getApplicationEventMulticaster().multicastEvent(earlyEvent);
}
}
}
--------------------------------------------------------------------如何发布事件------------------------------------------------------
public void multicastEvent(final ApplicationEvent event, ResolvableType eventType) {
ResolvableType type = (eventType != null ? eventType : resolveDefaultEventType(event));
//获取到所有的监听器
for (final ApplicationListener<?> listener : getApplicationListeners(event, type)) {
//看spring 容器中是否支持线程池 异步发送事件
Executor executor = getTaskExecutor();
if (executor != null) {
executor.execute(new Runnable() {
@Override
public void run() {
invokeListener(listener, event);
}
});
}
else { //同步发送事件
invokeListener(listener, event);
}
}
}
private void doInvokeListener(ApplicationListener listener, ApplicationEvent event) {
try {
//调用对于listener的onApplicationEvent事件
listener.onApplicationEvent(event);
}
catch (ClassCastException ex) {
String msg = ex.getMessage();
if (msg == null || matchesClassCastMessage(msg, event.getClass())) {
// Possibly a lambda-defined listener which we could not resolve the generic event type for
// -> let's suppress the exception and just log a debug message.
Log logger = LogFactory.getLog(getClass());
if (logger.isDebugEnabled()) {
logger.debug("Non-matching event type for listener: " + listener, ex);
}
}
else {
throw ex;
}
}
}
二:BeanDefinitionRegistryPostProcessor 的处理源码流程
执行时机:所有的bean定义信息将要被加载到容器中，Bean实例还没有被初始化。
@Component
public class TulingBeanDefinationRegisterPostProcessor implements BeanDefinitionRegistryPostProcessor {
@Override
public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
System.out.println("TulingBeanDefinationRegisterPostProcessor的postProcessBeanDefinitionRegistry方法");
System.out.println("bean定义的数据量:"+registry.getBeanDefinitionCount());
RootBeanDefinition rootBeanDefinition = new RootBeanDefinition(TulingLog.class);
registry.registerBeanDefinition("tulingLog",rootBeanDefinition);
}
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
System.out.println("TulingBeanDefinationRegisterPostProcessor的postProcessBeanFactory方法");
System.out.println(beanFactory.getBeanDefinitionCount());
}
}
三:BeanFactoryPostProcessor 处理流程
执行时间:所有的Bean定义信息已经加载到容器中，但是Bean实例还没有被初始化.
@Component
public class TulingBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
System.out.println("IOC 容器调用了TulingBeanFactoryPostProcessor的postProcessBeanFactory方法");
for(String name:beanFactory.getBeanDefinitionNames()) {
if("tulingLog".equals(name)) {
BeanDefinition beanDefinition = beanFactory.getBeanDefinition(name);
beanDefinition.setLazyInit(true);
}
}
}
}
调用链:
i1:org.springframework.context.support.AbstractApplicationContext#refresh
>i2:org.springframework.context.support.AbstractApplicationContext#invokeBeanFactoryPostProcessors
>i3:org.springframework.context.support.PostProcessorRegistrationDelegate#invokeBeanFactoryPostProcessors
>i4:org.springframework.context.support.PostProcessorRegistrationDelegate#invokeBeanDefinitionRegistryPostProcessors
>i5:org.springframework.context.annotation.ConfigurationClassPostProcessor#processConfigBeanDefinitions
> i6:org.springframework.context.annotation.ConfigurationClassParser#parse
>i7:org.springframework.context.annotation.ConfigurationClassParser#processConfigurationClass
>i8:org.springframework.context.annotation.ConfigurationClassParser#doProcessConfigurationClass
i4标记处源码解析org.springframework.context.support.PostProcessorRegistrationDelegate#invokeBeanFactoryPostProcessors
public static void invokeBeanFactoryPostProcessors(
ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {
// Invoke BeanDefinitionRegistryPostProcessors first, if any.
Set<String> processedBeans = new HashSet<String>();
//判断IOC 容器是不是BeanDefinitionRegistry的？
if (beanFactory instanceof BeanDefinitionRegistry) {
//把IOC容器 强制转为BeanDefinitionRegistry类型的
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
//创建一个普通的PostProcessors的list的组件
List<BeanFactoryPostProcessor> regularPostProcessors = new LinkedList<BeanFactoryPostProcessor>();
//创建一个BeanDefinitionRegistryPostProcessor类型的list
List<BeanDefinitionRegistryPostProcessor> registryProcessors = new LinkedList<BeanDefinitionRegistryPostProcessor>();
//处理容器硬编码(new 出来的)带入的beanFacotryPostProcessors
for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
//判断是不是BeanDefinitionRegistryPostProcessor
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
BeanDefinitionRegistryPostProcessor registryProcessor =
(BeanDefinitionRegistryPostProcessor) postProcessor;
//调用BeanDefinitionRegistryPostProcessor的postProcessBeanDefinitionRegistry
registryProcessor.postProcessBeanDefinitionRegistry(registry);
//加入到list集合中
registryProcessors.add(registryProcessor);
}
else {//判断不是BeanDefinitionRegistryPostProcessor
//加入到集合中
regularPostProcessors.add(postProcessor);
}
}
//创建一个当前注册的RegistryProcessors的集合
List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<BeanDefinitionRegistryPostProcessor>();
第一步:去容器中查询是否有BeanDefinitionRegistryPostProcessor类型的
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
//判断是不是实现了PriorityOrdered接口的
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
//添加到currentRegistryProcessors的集合中
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
//添加到processedBeans的集合中
processedBeans.add(ppName);
}
}
//进行排序
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
//调用BeanDefinitionRegistryPostProcessors的postProcessBeanDefinitionRegistry方法
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
第二步:去容器中查询是否有BeanDefinitionRegistryPostProcessor类型的
for (String ppName : postProcessorNames) {
//排除被处理过的，并且实现了Ordered接口的
if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
//加到以处理的list中
processedBeans.add(ppName);
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
//调用BeanDefinitionRegistryPostProcessors的postProcessBeanDefinitionRegistry方法
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
//调用普通的BeanDefinitionRegistryPostProcessors没用实现 PriorithOrdered和Ordered接口
boolean reiterate = true;
while (reiterate) {
reiterate = false;
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
if (!processedBeans.contains(ppName)) {
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
reiterate = true;
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
}
//调用上诉实现了也实现了BeanFactoryPostProcessors的接口
invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
}
else {
// Invoke factory processors registered with the context instance.
invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);
}
//去IOC 容器中获取BeanFactoryPostProcessor 类型的
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
//分离实现了PriorityOrdered接口的 Ordered 接口的 普通的
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);
}
}
调用 PriorityOrdered.
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);
//调用 Ordered.
List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();
for (String postProcessorName : orderedPostProcessorNames) {
orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
sortPostProcessors(orderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);
//调用普通的
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();
}
源码解析: i5:org.springframework.context.annotation.ConfigurationClassPostProcessor#processConfigBeanDefinitions
public void processConfigBeanDefinitions(BeanDefinitionRegistry registry) {
List<BeanDefinitionHolder> configCandidates = new ArrayList<BeanDefinitionHolder>();
//去IOC容器中的获取Bean定义的名称
// private volatile List<String> beanDefinitionNames = new ArrayList<String>(256);
//没有解析之前，系统候选的bean定义配置(有自己的 有系统自带的)
String[] candidateNames = registry.getBeanDefinitionNames();
//循环Bean定义的名称 找出自己的传入的主配置类的bean定义信息 configCandidates
for (String beanName : candidateNames) {
//去bean定义的map中获取对应的Bean定义对象
// private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<String, BeanDefinition>(256);
BeanDefinition beanDef = registry.getBeanDefinition(beanName);
//检查该bean定义对象是不是用来描述配置类
if (ConfigurationClassUtils.isFullConfigurationClass(beanDef) ||
ConfigurationClassUtils.isLiteConfigurationClass(beanDef)) {
if (logger.isDebugEnabled()) {
logger.debug("Bean definition has already been processed as a configuration class: " + beanDef);
}
}
else if (ConfigurationClassUtils.checkConfigurationClassCandidate(beanDef, this.metadataReaderFactory)) {
configCandidates.add(new BeanDefinitionHolder(beanDef, beanName));
}
}
// Return immediately if no @Configuration classes were found
if (configCandidates.isEmpty()) {
return;
}
//检查配置类排序
Collections.sort(configCandidates, new Comparator<BeanDefinitionHolder>() {
@Override
public int compare(BeanDefinitionHolder bd1, BeanDefinitionHolder bd2) {
int i1 = ConfigurationClassUtils.getOrder(bd1.getBeanDefinition());
int i2 = ConfigurationClassUtils.getOrder(bd2.getBeanDefinition());
return (i1 < i2) ? -1 : (i1 > i2) ? 1 : 0;
}
});
// bean的名称生成策略
SingletonBeanRegistry sbr = null;
if (registry instanceof SingletonBeanRegistry) {
sbr = (SingletonBeanRegistry) registry;
if (!this.localBeanNameGeneratorSet && sbr.containsSingleton(CONFIGURATION_BEAN_NAME_GENERATOR)) {
BeanNameGenerator generator = (BeanNameGenerator) sbr.getSingleton(CONFIGURATION_BEAN_NAME_GENERATOR);
this.componentScanBeanNameGenerator = generator;
this.importBeanNameGenerator = generator;
}
}
/***创建一个配置类解析器
1)元数据读取器工厂
this.metadataReaderFactory = metadataReaderFactory;
2)问题报告器
this.problemReporter = problemReporter;
//设置环境
this.environment = environment;
3)资源加载器
this.resourceLoader = resourceLoader;
4）创建了一个组件扫描器
this.componentScanParser = new ComponentScanAnnotationParser(
environment, resourceLoader, componentScanBeanNameGenerator, registry);
this.conditionEvaluator = new ConditionEvaluator(registry, environment, resourceLoader);
****/
ConfigurationClassParser parser = new ConfigurationClassParser(
this.metadataReaderFactory, this.problemReporter, this.environment,
this.resourceLoader, this.componentScanBeanNameGenerator, registry);
//将要被解析的配置类(把自己的configCandidates加入到 候选的)
Set<BeanDefinitionHolder> candidates = new LinkedHashSet<BeanDefinitionHolder>(configCandidates);
//已经被解析的配置类(由于do while 那么mainclass就一定会被解析,被解析的size为1)
Set<ConfigurationClass> alreadyParsed = new HashSet<ConfigurationClass>(configCandidates.size());
do {
//通过配置解析器真正的解析配置类
parser.parse(candidates);
//进行校验
parser.validate();
//获取ConfigClass (把解析过的配置bean定义信息获取出来)
Set<ConfigurationClass> configClasses = new LinkedHashSet<ConfigurationClass>(parser.getConfigurationClasses());
configClasses.removeAll(alreadyParsed);
// Read the model and create bean definitions based on its content
if (this.reader == null) {
this.reader = new ConfigurationClassBeanDefinitionReader(
registry, this.sourceExtractor, this.resourceLoader, this.environment,
this.importBeanNameGenerator, parser.getImportRegistry());
}
//@CompentScan是直接注册Bean定义信息的 但是通过获取@Import,@Bean这种的注解还没有注册的bean定义,
this.reader.loadBeanDefinitions(configClasses);
//把系统解析过我们自己的组件放在alreadyParsed
alreadyParsed.addAll(configClasses);
//清除解析过的 配置文件
candidates.clear();
//已经注册的bean定义个数大于最新 开始系统+主配置类的(发生过解析)
if (registry.getBeanDefinitionCount() > candidateNames.length) {
//获取系统+自己解析的+mainconfig的bean定义信息
String[] newCandidateNames = registry.getBeanDefinitionNames();
//系统的+mainconfig的bean定义信息
Set<String> oldCandidateNames = new HashSet<String>(Arrays.asList(candidateNames));
//已经解析过的自己的组件
Set<String> alreadyParsedClasses = new HashSet<String>();
for (ConfigurationClass configurationClass : alreadyParsed) {
alreadyParsedClasses.add(configurationClass.getMetadata().getClassName());
}
for (String candidateName : newCandidateNames) {
//老的（系统+mainconfig） 不包含解析的
if (!oldCandidateNames.contains(candidateName)) {
//把当前bean定义获取出来
BeanDefinition bd = registry.getBeanDefinition(candidateName);
//检查是否为解析过的
if (ConfigurationClassUtils.checkConfigurationClassCandidate(bd, this.metadataReaderFactory) &&
!alreadyParsedClasses.contains(bd.getBeanClassName())) {
//若不是解析过且通过检查的 把当前的bean定义 加入到candidates中
candidates.add(new BeanDefinitionHolder(bd, candidateName));
}
}
}
把解析过的赋值给原来的
candidateNames = newCandidateNames;
}
}
while (!candidates.isEmpty()); //还存主没有解析过的 再次解析
// Register the ImportRegistry as a bean in order to support ImportAware @Configuration classes
if (sbr != null) {
if (!sbr.containsSingleton(IMPORT_REGISTRY_BEAN_NAME)) {
sbr.registerSingleton(IMPORT_REGISTRY_BEAN_NAME, parser.getImportRegistry());
}
}
if (this.metadataReaderFactory instanceof CachingMetadataReaderFactory) {
((CachingMetadataReaderFactory) this.metadataReaderFactory).clearCache();
}
}
i6源码解析 :org.springframework.context.annotation.ConfigurationClassParser#parse
public void parse(Set<BeanDefinitionHolder> configCandidates) {
this.deferredImportSelectors = new LinkedList<DeferredImportSelectorHolder>();
for (BeanDefinitionHolder holder : configCandidates) {
BeanDefinition bd = holder.getBeanDefinition();
try {
//注解形式的bean定义信息
if (bd instanceof AnnotatedBeanDefinition) {
//解析配置类的bean定义
parse(((AnnotatedBeanDefinition) bd).getMetadata(), holder.getBeanName());
}
else if (bd instanceof AbstractBeanDefinition && ((AbstractBeanDefinition) bd).hasBeanClass()) {
parse(((AbstractBeanDefinition) bd).getBeanClass(), holder.getBeanName());
}
else {
parse(bd.getBeanClassName(), holder.getBeanName());
}
}
catch (BeanDefinitionStoreException ex) {
throw ex;
}
catch (Throwable ex) {
throw new BeanDefinitionStoreException(
"Failed to parse configuration class [" + bd.getBeanClassName() + "]", ex);
}
}
processDeferredImportSelectors();
}
org.springframework.context.annotation.ConfigurationClassParser#parse
org.springframework.context.annotation.ConfigurationClassParser#processConfigurationClass
protected void processConfigurationClass(ConfigurationClass configClass) throws IOException {
if (this.conditionEvaluator.shouldSkip(configClass.getMetadata(), ConfigurationPhase.PARSE_CONFIGURATION)) {
return;
}
ConfigurationClass existingClass = this.configurationClasses.get(configClass);
if (existingClass != null) {
if (configClass.isImported()) {
if (existingClass.isImported()) {
existingClass.mergeImportedBy(configClass);
}
// Otherwise ignore new imported config class; existing non-imported class overrides it.
return;
}
else {
// Explicit bean definition found, probably replacing an import.
// Let's remove the old one and go with the new one.
this.configurationClasses.remove(configClass);
for (Iterator<ConfigurationClass> it = this.knownSuperclasses.values().iterator(); it.hasNext();) {
if (configClass.equals(it.next())) {
it.remove();
}
}
}
}
递归处理配置类及其超类层次结构。
SourceClass sourceClass = asSourceClass(configClass);
do {
sourceClass = doProcessConfigurationClass(configClass, sourceClass);
}
while (sourceClass != null);
this.configurationClasses.put(configClass, configClass);
}
org.springframework.context.annotation.ConfigurationClassParser#doProcessConfigurationClass
protected final SourceClass doProcessConfigurationClass(ConfigurationClass configClass, SourceClass sourceClass)
throws IOException {
// Recursively process any member (nested) classes first
processMemberClasses(configClass, sourceClass);
//处理@PropertySource注解
for (AnnotationAttributes propertySource : AnnotationConfigUtils.attributesForRepeatable(
sourceClass.getMetadata(), PropertySources.class,
org.springframework.context.annotation.PropertySource.class)) {
if (this.environment instanceof ConfigurableEnvironment) {
processPropertySource(propertySource);
}
else {
logger.warn("Ignoring @PropertySource annotation on [" + sourceClass.getMetadata().getClassName() +
"]. Reason: Environment must implement ConfigurableEnvironment");
}
}
//处理@ComponentScan注解
//解析@ComponentScans注解的属性 封装成一个一个的componentscan对象
Set<AnnotationAttributes> componentScans = AnnotationConfigUtils.attributesForRepeatable(sourceClass.getMetadata(), ComponentScans.class, ComponentScan.class);
if (!componentScans.isEmpty() &&!this.conditionEvaluator.shouldSkip(sourceClass.getMetadata(), ConfigurationPhase.REGISTER_BEAN)) {
//循环componentScans的set
for (AnnotationAttributes componentScan : componentScans) {
// 立即执行扫描解析
Set<BeanDefinitionHolder> scannedBeanDefinitions =this.componentScanParser.parse(componentScan, sourceClass.getMetadata().getClassName());
//检查任何其他配置类的扫描定义集，并在需要时递归解析
for (BeanDefinitionHolder holder : scannedBeanDefinitions) {
//获取原始的bean定义信息
BeanDefinition bdCand = holder.getBeanDefinition().getOriginatingBeanDefinition();
if (bdCand == null) {
bdCand = holder.getBeanDefinition();
}
//检查当前的bean定义信息是不是配置类 比如MainConfig的bean定义信息
if (ConfigurationClassUtils.checkConfigurationClassCandidate(bdCand, this.metadataReaderFactory)) {
//递归调用来解析MainConfig,解析出来配置类的中导入的bean定义信息
parse(bdCand.getBeanClassName(), holder.getBeanName());
}
}
}
}
//处理@Import注解 解析Import 注解的ImportSelector ImportBeanDefinitionRegister,@Bean这种
//存放在ConfigClass中
processImports(configClass, sourceClass, getImports(sourceClass), true);
//处理 @ImportResource annotations
if (sourceClass.getMetadata().isAnnotated(ImportResource.class.getName())) {
AnnotationAttributes importResource =
AnnotationConfigUtils.attributesFor(sourceClass.getMetadata(), ImportResource.class);
String[] resources = importResource.getStringArray("locations");
Class<? extends BeanDefinitionReader> readerClass = importResource.getClass("reader");
for (String resource : resources) {
String resolvedResource = this.environment.resolveRequiredPlaceholders(resource);
configClass.addImportedResource(resolvedResource, readerClass);
}
}
// 处理 @Bean methods
Set<MethodMetadata> beanMethods = retrieveBeanMethodMetadata(sourceClass);
for (MethodMetadata methodMetadata : beanMethods) {
configClass.addBeanMethod(new BeanMethod(methodMetadata, configClass));
}
//处理接口
processInterfaces(configClass, sourceClass);
// 处理超类的
if (sourceClass.getMetadata().hasSuperClass()) {
String superclass = sourceClass.getMetadata().getSuperClassName();
if (!superclass.startsWith("java") && !this.knownSuperclasses.containsKey(superclass)) {
this.knownSuperclasses.put(superclass, configClass);
// Superclass found, return its annotation metadata and recurse
return sourceClass.getSuperClass();
}
}
// No superclass -> processing is complete
return null;
}
//通过组件扫描器进行真正的解析
org.springframework.context.annotation.ComponentScanAnnotationParser#parse
Set<BeanDefinitionHolder>
public Set<BeanDefinitionHolder> parse(AnnotationAttributes componentScan, final String declaringClass) {
Assert.state(this.environment != null, "Environment must not be null");
Assert.state(this.resourceLoader != null, "ResourceLoader must not be null");
//创建一个类路径下的bean定义扫描器
ClassPathBeanDefinitionScanner scanner = new ClassPathBeanDefinitionScanner(this.registry,
componentScan.getBoolean("useDefaultFilters"), this.environment, this.resourceLoader);
//为扫描器设置一个bean 名称的生成器
Class<? extends BeanNameGenerator> generatorClass = componentScan.getClass("nameGenerator");
boolean useInheritedGenerator = (BeanNameGenerator.class == generatorClass);
scanner.setBeanNameGenerator(useInheritedGenerator ? this.beanNameGenerator :
BeanUtils.instantiateClass(generatorClass));
ScopedProxyMode scopedProxyMode = componentScan.getEnum("scopedProxy");
if (scopedProxyMode != ScopedProxyMode.DEFAULT) {
scanner.setScopedProxyMode(scopedProxyMode);
}
else {
Class<? extends ScopeMetadataResolver> resolverClass = componentScan.getClass("scopeResolver");
scanner.setScopeMetadataResolver(BeanUtils.instantiateClass(resolverClass));
}
scanner.setResourcePattern(componentScan.getString("resourcePattern"));
for (AnnotationAttributes filter : componentScan.getAnnotationArray("includeFilters")) {
for (TypeFilter typeFilter : typeFiltersFor(filter)) {
scanner.addIncludeFilter(typeFilter);
}
}
for (AnnotationAttributes filter : componentScan.getAnnotationArray("excludeFilters")) {
for (TypeFilter typeFilter : typeFiltersFor(filter)) {
scanner.addExcludeFilter(typeFilter);
}
}
boolean lazyInit = componentScan.getBoolean("lazyInit");
if (lazyInit) {
scanner.getBeanDefinitionDefaults().setLazyInit(true);
}
Set<String> basePackages = new LinkedHashSet<String>();
String[] basePackagesArray = componentScan.getStringArray("basePackages");
for (String pkg : basePackagesArray) {
String[] tokenized = StringUtils.tokenizeToStringArray(this.environment.resolvePlaceholders(pkg),
ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
basePackages.addAll(Arrays.asList(tokenized));
}
for (Class<?> clazz : componentScan.getClassArray("basePackageClasses")) {
basePackages.add(ClassUtils.getPackageName(clazz));
}
if (basePackages.isEmpty()) {
basePackages.add(ClassUtils.getPackageName(declaringClass));
}
scanner.addExcludeFilter(new AbstractTypeHierarchyTraversingFilter(false, false) {
@Override
protected boolean matchClassName(String className) {
return declaringClass.equals(className);
}
});
//真正扫描器扫描指定路径
return scanner.doScan(StringUtils.toStringArray(basePackages));
}
//创建类路径下的bean定义扫描器
public ClassPathBeanDefinitionScanner(BeanDefinitionRegistry registry, boolean useDefaultFilters,
Environment environment, ResourceLoader resourceLoader) {
Assert.notNull(registry, "BeanDefinitionRegistry must not be null");
this.registry = registry;
//使用默认的扫描规则
if (useDefaultFilters) {
registerDefaultFilters();
}
//设置环境变量
setEnvironment(environment);
//设置资源加载器
setResourceLoader(resourceLoader);
}
//默认的扫描规则
protected void registerDefaultFilters() {
//添加了Componet的解析，这就是我们为啥@Componet @Respository @Service @Controller的 @AspectJ
this.includeFilters.add(new AnnotationTypeFilter(Component.class));
ClassLoader cl = ClassPathScanningCandidateComponentProvider.class.getClassLoader();
try {
//添加Jsr 250规范的注解
this.includeFilters.add(new AnnotationTypeFilter(
((Class<? extends Annotation>) ClassUtils.forName("javax.annotation.ManagedBean", cl)), false));
logger.debug("JSR-250 'javax.annotation.ManagedBean' found and supported for component scanning");
}
catch (ClassNotFoundException ex) {
// JSR-250 1.1 API (as included in Java EE 6) not available - simply skip.
}
try {
//JSR330的注解
this.includeFilters.add(new AnnotationTypeFilter(
((Class<? extends Annotation>) ClassUtils.forName("javax.inject.Named", cl)), false));
logger.debug("JSR-330 'javax.inject.Named' annotation found and supported for component scanning");
}
catch (ClassNotFoundException ex) {
// JSR-330 API not available - simply skip.
}
}
使用扫描器去真正的扫描类,返回Set<BeanDefinitionHolder>
org.springframework.context.annotation.ClassPathBeanDefinitionScanner#doScan
protected Set<BeanDefinitionHolder> doScan(String... basePackages) {
Assert.notEmpty(basePackages, "At least one base package must be specified");
//创建一个Bean定义 holder的 set
Set<BeanDefinitionHolder> beanDefinitions = new LinkedHashSet<BeanDefinitionHolder>();
//循环扫描路径
for (String basePackage : basePackages) {
//找到候选的组件集合
Set<BeanDefinition> candidates = findCandidateComponents(basePackage);
//循环候选组件集合
for (BeanDefinition candidate : candidates) {
ScopeMetadata scopeMetadata = this.scopeMetadataResolver.resolveScopeMetadata(candidate);
candidate.setScope(scopeMetadata.getScopeName());
//生成bean的名称
String beanName = this.beanNameGenerator.generateBeanName(candidate, this.registry);
//判断是不是抽象的beand定义
if (candidate instanceof AbstractBeanDefinition) {
postProcessBeanDefinition((AbstractBeanDefinition) candidate, beanName);
}
//注解的bean定义西悉尼
if (candidate instanceof AnnotatedBeanDefinition) {
AnnotationConfigUtils.processCommonDefinitionAnnotations((AnnotatedBeanDefinition) candidate);
}
if (checkCandidate(beanName, candidate)) { //检查当前的和存主的bean定义是否有冲突
//把候选的组件封装成BeanDefinitionHolder
BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(candidate, beanName);
definitionHolder =AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry);
//加入到bean定义的集合中
beanDefinitions.add(definitionHolder);
//注册当前的bean定义信息
registerBeanDefinition(definitionHolder, this.registry);
}
}
}
return beanDefinitions;
}
org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider#findCandidateComponents
找到候选的组件 返回Set<BeanDefinition>的集合
public Set<BeanDefinition> findCandidateComponents(String basePackage) {
//候选的bean定义信息
Set<BeanDefinition> candidates = new LinkedHashSet<BeanDefinition>();
try {
//拼接需要扫描包下面的类的路径 classpath*:com/tuling/testapplicationlistener/**/*.class
String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX +
resolveBasePackage(basePackage) + '/' + this.resourcePattern;
//把路径解析成一个个.class文件
Resource[] resources = this.resourcePatternResolver.getResources(packageSearchPath);
boolean traceEnabled = logger.isTraceEnabled();
boolean debugEnabled = logger.isDebugEnabled();
//循环.class文件的resource对象
for (Resource resource : resources) {
if (traceEnabled) {
logger.trace("Scanning " + resource);
}
//判断class文件是否可读
if (resource.isReadable()) {
try {
//把resource对象 变为一个类的原信息读取器
MetadataReader metadataReader = this.metadataReaderFactory.getMetadataReader(resource);
//判断类的源信息读取器是否为候选的组件
if (isCandidateComponent(metadataReader)) { //是候选的组件
//把类元信息读取器封装成一个ScannedGenericBeanDefinition
ScannedGenericBeanDefinition sbd = new ScannedGenericBeanDefinition(metadataReader);
sbd.setResource(resource);
sbd.setSource(resource);
//是候选的组件
if (isCandidateComponent(sbd)) {
if (debugEnabled) {
logger.debug("Identified candidate component class: " + resource);
}
//把当前解析出来的定义的加入到 BeanDefinition的集合中
candidates.add(sbd);
}
else {
if (debugEnabled) {
logger.debug("Ignored because not a concrete top-level class: " + resource);
}
}
}
else {
if (traceEnabled) {
logger.trace("Ignored because not matching any filter: " + resource);
}
}
}
catch (Throwable ex) {
throw new BeanDefinitionStoreException(
"Failed to read candidate component class: " + resource, ex);
}
}
else {
if (traceEnabled) {
logger.trace("Ignored because not readable: " + resource);
}
}
}
}
catch (IOException ex) {
throw new BeanDefinitionStoreException("I/O failure during classpath scanning", ex);
}
return candidates;
}
是不是需要扫描的组件
org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider#isCandidateComponent
protected boolean isCandidateComponent(MetadataReader metadataReader) throws IOException {
//是不是被排除的
for (TypeFilter tf : this.excludeFilters) {
if (tf.match(metadataReader, this.metadataReaderFactory)) {
return false;
}
}
//在被包含的组件
for (TypeFilter tf : this.includeFilters) {
if (tf.match(metadataReader, this.metadataReaderFactory)) {
return isConditionMatch(metadataReader);
}
}
return false;
}
是否能够进行@Conditional判断
org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider#isConditionMatch
private boolean isConditionMatch(MetadataReader metadataReader) {
if (this.conditionEvaluator == null) {
this.conditionEvaluator = new ConditionEvaluator(getRegistry(), getEnvironment(), getResourceLoader());
}
return !this.conditionEvaluator.shouldSkip(metadataReader.getAnnotationMetadata());
}
BeanFactoryPostProcessor
