Spring源码-12-配置类解析器ConfigurationClassParser
解析配置类
// ConfigurationClassParser.java
public void parse(Set<BeanDefinitionHolder> configCandidates) {
for (BeanDefinitionHolder holder : configCandidates) {
BeanDefinition bd = holder.getBeanDefinition();
try {
if (bd instanceof AnnotatedBeanDefinition) {
this.parse(((AnnotatedBeanDefinition) bd).getMetadata(), holder.getBeanName());
}
else if (bd instanceof AbstractBeanDefinition && ((AbstractBeanDefinition) bd).hasBeanClass()) {
this.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);
}
}
/**
* 处理延迟ImportSelector
*/
this.deferredImportSelectorHandler.process();
}
// ConfigurationClassParser.java
protected void processConfigurationClass(ConfigurationClass configClass, Predicate<String> filter) 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);
this.knownSuperclasses.values().removeIf(configClass::equals);
}
}
// Recursively process the configuration class and its superclass hierarchy.
SourceClass sourceClass = asSourceClass(configClass, filter);
/**
* 显式继承场景
* - 配置类没有父类 返回null
* - 配置类有父类 返回父类 递归解析父类
*/
do {
sourceClass = this.doProcessConfigurationClass(configClass, sourceClass, filter);
}
while (sourceClass != null);
this.configurationClasses.put(configClass, configClass);
}
// ConfigurationClassParser.java
@Nullable
protected final SourceClass doProcessConfigurationClass(
ConfigurationClass configClass, SourceClass sourceClass, Predicate<String> filter)
throws IOException {
/**
* @Configuration是组合注解
* - @Component
*/
if (configClass.getMetadata().isAnnotated(Component.class.getName())) {
// Recursively process any member (nested) classes first
/**
* 配置的内部类
* - 内部类也是配置类 dfs解析下去
*/
this.processMemberClasses(configClass, sourceClass, filter);
}
// Process any @PropertySource annotations
/**
* 配置类上的@PropertySource解析
* - 单个@PropertySource
* - 多个@PropertySource
* - @PropertySources定义的多个@PropertySource
* for轮询中处理每个@PropertySource
* 将@PrepertySource指定的配置文件解析加载到Environment中
*/
for (AnnotationAttributes propertySource : AnnotationConfigUtils.attributesForRepeatable(
sourceClass.getMetadata(), PropertySources.class,
org.springframework.context.annotation.PropertySource.class)) {
if (this.propertySourceRegistry != null) {
this.propertySourceRegistry.processPropertySource(propertySource); // 处理每个@PropertySource
}
else {
logger.info("Ignoring @PropertySource annotation on [" + sourceClass.getMetadata().getClassName() +
"]. Reason: Environment must implement ConfigurableEnvironment");
}
}
// Process any @ComponentScan annotations
/**
* 配置类上的@ComponentScan注解解析
* - 单个@CompoentScan
* - 多个@ComponentScan
* - @ComponentScans定义的多个@ComponentScan
* - 扫包路径下@Component/类@Component的类封装BeanDefinition注册进Bean工厂
* - 扫描到的配置类递归继续解析
*/
Set<AnnotationAttributes> componentScans = AnnotationConfigUtils.attributesForRepeatable(
sourceClass.getMetadata(), ComponentScans.class, ComponentScan.class);
if (!componentScans.isEmpty() &&
!this.conditionEvaluator.shouldSkip(sourceClass.getMetadata(), ConfigurationPhase.REGISTER_BEAN)) {
for (AnnotationAttributes componentScan : componentScans) {
// The config class is annotated with @ComponentScan -> perform the scan immediately
/**
* 扫包路径下符合要求的类被封装成ScannedGenericBeanDefinition
* - @Component/类@Component注解标识的类
*/
Set<BeanDefinitionHolder> scannedBeanDefinitions =
this.componentScanParser.parse(componentScan, sourceClass.getMetadata().getClassName()); // 配置类名称
// Check the set of scanned definitions for any further config classes and parse recursively if needed
for (BeanDefinitionHolder holder : scannedBeanDefinitions) { // 扫包出来的BeanDefinition可能本身也是配置类
BeanDefinition bdCand = holder.getBeanDefinition().getOriginatingBeanDefinition();
if (bdCand == null) {
bdCand = holder.getBeanDefinition();
}
if (ConfigurationClassUtils.checkConfigurationClassCandidate(bdCand, this.metadataReaderFactory)) { // 扫到的类也是配置类就继续递归解析下去
this.parse(bdCand.getBeanClassName(), holder.getBeanName());
}
}
}
}
// Process any @Import annotations
/**
* @Import注解的配置类
* getImports(...)找出配置类上通过@Import注解导入的的所有类
* 解析@Import注解导入的类 根据导入的类进行不同的策略处理
* - ImportSelector的实现
* - selectImports(...)定义的类按照Import类递归解析
* - ImportBeanDefinitionRegistrar的实现
* - 将ImportBeanDefinitionRegistrar缓存到配置类的importBeanDefinitionRegistrars
* - 没有实现ImportSelector和ImportBeanDefinitionRegistry接口的类
* - 配置类就递归解析下去
* - 普通类就缓存到imports哈希表中
* - 不发生注册Bean工厂
*/
this.processImports(configClass, sourceClass, this.getImports(sourceClass), filter, true);
// Process any @ImportResource annotations
/**
* @ImportResource引入的配置文件
* 将@ImportResource指定的配置文件资源缓存在配置类的importedResources中
*/
AnnotationAttributes importResource =
AnnotationConfigUtils.attributesFor(sourceClass.getMetadata(), ImportResource.class); // 配置上的@ImportResource注解对象
if (importResource != null) {
String[] resources = importResource.getStringArray("locations"); // 指定的配置文件路径
Class<? extends BeanDefinitionReader> readerClass = importResource.getClass("reader");
for (String resource : resources) {
String resolvedResource = this.environment.resolveRequiredPlaceholders(resource);
configClass.addImportedResource(resolvedResource, readerClass); // 缓存在配置类的importedResources中
}
}
// Process individual @Bean methods
/**
* @Bean注解的方法
* 将@Bean注解的方法缓存在配置类的beanMethods中
*/
Set<MethodMetadata> beanMethods = retrieveBeanMethodMetadata(sourceClass); // 配置类被@Bean标识的方法
for (MethodMetadata methodMetadata : beanMethods) {
configClass.addBeanMethod(new BeanMethod(methodMetadata, configClass)); // 缓存在配置类的beanMethods中
}
// Process default methods on interfaces
processInterfaces(configClass, sourceClass);
// Process superclass, if any
if (sourceClass.getMetadata().hasSuperClass()) {
String superclass = sourceClass.getMetadata().getSuperClassName();
if (superclass != null && !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;
}
一 内部类
配置中的内部类也是配置类就递归下去
// ConfigurationClassParser.java
/**
* 配置的内部类
* - 内部类也是配置类 dfs解析下去
*/
this.processMemberClasses(configClass, sourceClass, filter);
// ConfigurationClassParser.java
private void processMemberClasses(ConfigurationClass configClass, SourceClass sourceClass,
Predicate<String> filter) throws IOException {
Collection<SourceClass> memberClasses = sourceClass.getMemberClasses(); // 配置类的内部类
if (!memberClasses.isEmpty()) {
List<SourceClass> candidates = new ArrayList<>(memberClasses.size());
for (SourceClass memberClass : memberClasses) {
if (ConfigurationClassUtils.isConfigurationCandidate(memberClass.getMetadata()) &&
!memberClass.getMetadata().getClassName().equals(configClass.getMetadata().getClassName())) {
candidates.add(memberClass); // 内部类也是配置类 缓存起来
}
}
OrderComparator.sort(candidates);
for (SourceClass candidate : candidates) {
if (this.importStack.contains(configClass)) {
this.problemReporter.error(new CircularImportProblem(configClass, this.importStack));
}
else {
this.importStack.push(configClass); // 入栈出栈解决多层嵌套内部类场景
try {
this.processConfigurationClass(candidate.asConfigClass(configClass), filter); // 解析配置类
}
finally {
this.importStack.pop();
}
}
}
}
}
二 @PropertySource
将资源文件中的配置加载到Environment中
- @PropertySource
- @PropertySources
// ConfigurationClassParser.java
this.propertySourceRegistry.processPropertySource(propertySource); // 处理每个@PropertySource
// PropertySourceRegistry.java
void processPropertySource(AnnotationAttributes propertySource) throws IOException { // 读取@PropertySource注解元素中的值
String name = propertySource.getString("name"); // @PropertySource的name值
if (!StringUtils.hasLength(name)) {
name = null;
}
String encoding = propertySource.getString("encoding"); // @PropertySource的encoding值
if (!StringUtils.hasLength(encoding)) {
encoding = null;
}
String[] locations = propertySource.getStringArray("value"); // @PropertySource的locations值 配置文件路径
Assert.isTrue(locations.length > 0, "At least one @PropertySource(value) location is required");
boolean ignoreResourceNotFound = propertySource.getBoolean("ignoreResourceNotFound");
Class<? extends PropertySourceFactory> factoryClass = propertySource.getClass("factory");
Class<? extends PropertySourceFactory> factorClassToUse =
(factoryClass != PropertySourceFactory.class ? factoryClass : null);
PropertySourceDescriptor descriptor = new PropertySourceDescriptor(Arrays.asList(locations), ignoreResourceNotFound, name,
factorClassToUse, encoding); // 封装@PropertySource注解元素中的值
this.propertySourceProcessor.processPropertySource(descriptor);
this.descriptors.add(descriptor);
}
// PropertySourceRegistry.java
public void processPropertySource(PropertySourceDescriptor descriptor) throws IOException {
String name = descriptor.name();
String encoding = descriptor.encoding();
List<String> locations = descriptor.locations();
Assert.isTrue(locations.size() > 0, "At least one @PropertySource(value) location is required");
boolean ignoreResourceNotFound = descriptor.ignoreResourceNotFound();
PropertySourceFactory factory = (descriptor.propertySourceFactory() != null
? instantiateClass(descriptor.propertySourceFactory())
: DEFAULT_PROPERTY_SOURCE_FACTORY);
for (String location : locations) { // 配置在@PropertySource中的配置文件路径
try {
String resolvedLocation = this.environment.resolveRequiredPlaceholders(location);
Resource resource = this.resourceLoader.getResource(resolvedLocation);
this.addPropertySource(factory.createPropertySource(name, new EncodedResource(resource, encoding))); // 配置文件配置项加载到Environment中
}
catch (IllegalArgumentException | FileNotFoundException | UnknownHostException | SocketException ex) {
// Placeholders not resolvable or resource not found when trying to open it
if (ignoreResourceNotFound) {
if (logger.isInfoEnabled()) {
logger.info("Properties location [" + location + "] not resolvable: " + ex.getMessage());
}
}
else {
throw ex;
}
}
}
}
// PropertySourceProcessor.java
private void addPropertySource(org.springframework.core.env.PropertySource<?> propertySource) {
String name = propertySource.getName();
MutablePropertySources propertySources = this.environment.getPropertySources(); // 将配置文件中的配置加载到environment中
if (this.propertySourceNames.contains(name)) {
// We've already added a version, we need to extend it
org.springframework.core.env.PropertySource<?> existing = propertySources.get(name);
if (existing != null) {
PropertySource<?> newSource = (propertySource instanceof ResourcePropertySource ?
((ResourcePropertySource) propertySource).withResourceName() : propertySource);
if (existing instanceof CompositePropertySource) {
((CompositePropertySource) existing).addFirstPropertySource(newSource);
}
else {
if (existing instanceof ResourcePropertySource) {
existing = ((ResourcePropertySource) existing).withResourceName();
}
CompositePropertySource composite = new CompositePropertySource(name);
composite.addPropertySource(newSource);
composite.addPropertySource(existing);
propertySources.replace(name, composite);
}
return;
}
}
if (this.propertySourceNames.isEmpty()) {
propertySources.addLast(propertySource);
}
else {
String firstProcessed = this.propertySourceNames.get(this.propertySourceNames.size() - 1);
propertySources.addBefore(firstProcessed, propertySource);
}
this.propertySourceNames.add(name);
}
三 @ComponentScan
定义扫包路径
- @ComponentScan
- @ComponentScans
筛选出符合过滤规则(类Component)的类注册Bean工厂，配置类递归解析
1 扫包路径下类Component
// ConfigurationClassParser.java
/**
* 扫包路径下符合要求的类被封装成ScannedGenericBeanDefinition
* - @Component/类@Component注解标识的类
*/
Set<BeanDefinitionHolder> scannedBeanDefinitions =
this.componentScanParser.parse(componentScan, sourceClass.getMetadata().getClassName()); // 配置类名称
// ComponentScanAnnotationParser.java
public Set<BeanDefinitionHolder> parse(AnnotationAttributes componentScan, String declaringClass) {
ClassPathBeanDefinitionScanner scanner = new ClassPathBeanDefinitionScanner(this.registry,
componentScan.getBoolean("useDefaultFilters"), this.environment, this.resourceLoader);
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 includeFilterAttributes : componentScan.getAnnotationArray("includeFilters")) {
List<TypeFilter> typeFilters = TypeFilterUtils.createTypeFiltersFor(includeFilterAttributes, this.environment,
this.resourceLoader, this.registry);
for (TypeFilter typeFilter : typeFilters) {
scanner.addIncludeFilter(typeFilter);
}
}
for (AnnotationAttributes excludeFilterAttributes : componentScan.getAnnotationArray("excludeFilters")) {
List<TypeFilter> typeFilters = TypeFilterUtils.createTypeFiltersFor(excludeFilterAttributes, this.environment,
this.resourceLoader, this.registry);
for (TypeFilter typeFilter : typeFilters) {
scanner.addExcludeFilter(typeFilter);
}
}
boolean lazyInit = componentScan.getBoolean("lazyInit");
if (lazyInit) {
scanner.getBeanDefinitionDefaults().setLazyInit(true);
}
Set<String> basePackages = new LinkedHashSet<>();
String[] basePackagesArray = componentScan.getStringArray("basePackages"); // @ComponentScan中定义的扫包路径
for (String pkg : basePackagesArray) {
String[] tokenized = StringUtils.tokenizeToStringArray(this.environment.resolvePlaceholders(pkg),
ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
Collections.addAll(basePackages, 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);
}
});
return scanner.doScan(StringUtils.toStringArray(basePackages)); // 扫描指定扫包路径 @Component/类@Component标识的类封装成BeanDefnition注册到Bean工厂
}
// ClassPathBeanDefinitionScanner.java
protected Set<BeanDefinitionHolder> doScan(String... basePackages) {
Assert.notEmpty(basePackages, "At least one base package must be specified");
Set<BeanDefinitionHolder> beanDefinitions = new LinkedHashSet<>();
for (String basePackage : basePackages) {
Set<BeanDefinition> candidates = findCandidateComponents(basePackage); // 定义的扫包路径下被@Component标识的类被封装成ScannedGenericBeanDefinition
for (BeanDefinition candidate : candidates) {
ScopeMetadata scopeMetadata = this.scopeMetadataResolver.resolveScopeMetadata(candidate);
candidate.setScope(scopeMetadata.getScopeName());
String beanName = this.beanNameGenerator.generateBeanName(candidate, this.registry);
if (candidate instanceof AbstractBeanDefinition) {
postProcessBeanDefinition((AbstractBeanDefinition) candidate, beanName);
}
if (candidate instanceof AnnotatedBeanDefinition) {
AnnotationConfigUtils.processCommonDefinitionAnnotations((AnnotatedBeanDefinition) candidate);
}
if (checkCandidate(beanName, candidate)) {
BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(candidate, beanName);
definitionHolder =
AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry);
beanDefinitions.add(definitionHolder);
registerBeanDefinition(definitionHolder, this.registry); // BeanDefinition注册到Bean工厂
}
}
}
return beanDefinitions;
}
1.1 @Component/类@Component注解的类
// ClassPathBeanDefinitionScanner.java
Set<BeanDefinition> candidates = super.findCandidateComponents(basePackage); // 定义的扫包路径下被@Component标识的类被封装成ScannedGenericBeanDefinition
// ClassPathScanningCandidateComponentProvider.java
public Set<BeanDefinition> findCandidateComponents(String basePackage) {
if (this.componentsIndex != null && indexSupportsIncludeFilters()) {
return addCandidateComponentsFromIndex(this.componentsIndex, basePackage);
}
else {
return this.scanCandidateComponents(basePackage);
}
}
// ClassPathScanningCandidateComponentProvider.java
private Set<BeanDefinition> scanCandidateComponents(String basePackage) {
Set<BeanDefinition> candidates = new LinkedHashSet<>();
try {
String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX +
resolveBasePackage(basePackage) + '/' + this.resourcePattern;
Resource[] resources = getResourcePatternResolver().getResources(packageSearchPath);
boolean traceEnabled = logger.isTraceEnabled();
boolean debugEnabled = logger.isDebugEnabled();
for (Resource resource : resources) {
String filename = resource.getFilename();
if (filename != null && filename.contains(ClassUtils.CGLIB_CLASS_SEPARATOR)) {
// Ignore CGLIB-generated classes in the classpath
continue;
}
if (traceEnabled) {
logger.trace("Scanning " + resource);
}
try {
MetadataReader metadataReader = getMetadataReaderFactory().getMetadataReader(resource);
if (this.isCandidateComponent(metadataReader)) { // 扫包路径下的@Component或者类@Component标识的类才会被封装成Definition
ScannedGenericBeanDefinition sbd = new ScannedGenericBeanDefinition(metadataReader); // BeanDefinition的实现标识是扫描出来的类封装的
sbd.setSource(resource);
if (isCandidateComponent(sbd)) {
if (debugEnabled) {
logger.debug("Identified candidate component class: " + resource);
}
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 (FileNotFoundException ex) {
if (traceEnabled) {
logger.trace("Ignored non-readable " + resource + ": " + ex.getMessage());
}
}
catch (Throwable ex) {
throw new BeanDefinitionStoreException(
"Failed to read candidate component class: " + resource, ex);
}
}
}
catch (IOException ex) {
throw new BeanDefinitionStoreException("I/O failure during classpath scanning", ex);
}
return candidates;
}
1.2 BeanDefinition注册Bean工厂
// ClassPathBeanDefinitionScanner.java
registerBeanDefinition(definitionHolder, this.registry); // BeanDefinition注册到Bean工厂
2 递归解析配置类
// ConfigurationClassParser.java
if (ConfigurationClassUtils.checkConfigurationClassCandidate(bdCand, this.metadataReaderFactory)) { // 扫到的类也是配置类就继续递归解析下去
this.parse(bdCand.getBeanClassName(), holder.getBeanName());
}
四 @Import
// ConfigurationClassParser.java
/**
* @Import注解的配置类
* getImports(...)找出配置类上通过@Import注解导入的的所有类
* 解析@Import注解导入的类 根据导入的类进行不同的策略处理
* - ImportSelector的实现
* - selectImports(...)定义的类按照Import类递归解析
* - ImportBeanDefinitionRegistrar的实现
* - 将ImportBeanDefinitionRegistrar缓存到配置类的importBeanDefinitionRegistrars
* - 没有实现ImportSelector和ImportBeanDefinitionRegistry接口的类
* - 配置类就递归解析下去
* - 普通类就缓存到imports哈希表中
* - 不发生注册Bean工厂
*/
this.processImports(configClass, sourceClass, this.getImports(sourceClass), filter, true);
// ConfigurationClassParser.java
/**
* @Import进来的类
* - 实现了ImportSelector
* - 递归解析通过selectImports(...)进来的所有类
* - 实现了ImportBeanDefinitionRegistrar
* - 将ImportBeanDefinitionRegistrar缓存到importBeanDefinitionRegistrars
* - 没有实现ImportSelector ImportBeanDefinitionRegistry
* - 当成配置类贪心解析一次
* - 如果仅仅是一个普通类 不会发生注册Bean工厂
*/
private void processImports(ConfigurationClass configClass, SourceClass currentSourceClass,
Collection<SourceClass> importCandidates, Predicate<String> exclusionFilter,
boolean checkForCircularImports) {
if (importCandidates.isEmpty()) {
return;
}
if (checkForCircularImports && isChainedImportOnStack(configClass)) {
this.problemReporter.error(new CircularImportProblem(configClass, this.importStack));
}
else {
this.importStack.push(configClass); // 递归栈 import进来的类本身又有@Import
try {
for (SourceClass candidate : importCandidates) { // import的类
if (candidate.isAssignable(ImportSelector.class)) { // ImportSelector接口的实现
// Candidate class is an ImportSelector -> delegate to it to determine imports
Class<?> candidateClass = candidate.loadClass();
ImportSelector selector = ParserStrategyUtils.instantiateClass(candidateClass, ImportSelector.class,
this.environment, this.resourceLoader, this.registry); // 实现类对ImportSelector声明的方法具体实现
Predicate<String> selectorFilter = selector.getExclusionFilter();
if (selectorFilter != null) {
exclusionFilter = exclusionFilter.or(selectorFilter);
}
if (selector instanceof DeferredImportSelector) {
this.deferredImportSelectorHandler.handle(configClass, (DeferredImportSelector) selector);
}
else {
String[] importClassNames = selector.selectImports(currentSourceClass.getMetadata()); // selectImports(...)方法的返回值
Collection<SourceClass> importSourceClasses = asSourceClasses(importClassNames, exclusionFilter);
this.processImports(configClass, currentSourceClass, importSourceClasses, exclusionFilter, false); // 递归解析ImportSelector定义的所有的类
}
}
else if (candidate.isAssignable(ImportBeanDefinitionRegistrar.class)) { // ImportBeanDefinitionRegistrar接口的实现
// Candidate class is an ImportBeanDefinitionRegistrar ->
// delegate to it to register additional bean definitions
Class<?> candidateClass = candidate.loadClass();
ImportBeanDefinitionRegistrar registrar =
ParserStrategyUtils.instantiateClass(candidateClass, ImportBeanDefinitionRegistrar.class,
this.environment, this.resourceLoader, this.registry);
configClass.addImportBeanDefinitionRegistrar(registrar, currentSourceClass.getMetadata()); // 将ImportBeanDefinitionRegistrar缓存到importBeanDefinitionRegistrars
}
else { // 把它当成配置类再解析一次 如果仅仅是import了普通类 并不会发生注册Bean工厂
// Candidate class not an ImportSelector or ImportBeanDefinitionRegistrar ->
// process it as an @Configuration class
this.importStack.registerImport(
currentSourceClass.getMetadata(), candidate.getMetadata().getClassName());
this.processConfigurationClass(candidate.asConfigClass(configClass), exclusionFilter); // 当成配置类进行解析 在配置类的imported中缓存主动import的类 记录当前类是被谁import进来的
}
}
}
catch (BeanDefinitionStoreException ex) {
throw ex;
}
catch (Throwable ex) {
throw new BeanDefinitionStoreException(
"Failed to process import candidates for configuration class [" +
configClass.getMetadata().getClassName() + "]: " + ex.getMessage(), ex);
}
finally {
this.importStack.pop();
}
}
}
对import的类进行解析
- ImportSelector实现
- ImportBeanDefinitionRegistry实现
- 普通类
1 ImportSelector的实现
// ConfigurationClassParser.java
this.processImports(configClass, currentSourceClass, importSourceClasses, exclusionFilter, false); // 递归解析ImportSelector定义的所有的类
2 ImportBeanDefinitionRegistrar的实现
// ConfigurationClassParser.java
configClass.addImportBeanDefinitionRegistrar(registrar, currentSourceClass.getMetadata()); // 将ImportBeanDefinitionRegistrar缓存到importBeanDefinitionRegistrars
3 没有实现ImportSelector和ImportBeanDefinitionRegistrar
// ConfigurationClassParser.java
this.processConfigurationClass(candidate.asConfigClass(configClass), exclusionFilter); // 当成配置类进行解析 在配置类的imported中缓存主动import的类 记录当前类是被谁import进来的
五 @ImportResource
// ConfigurationClassParser.java
/**
* @ImportResource引入的配置文件
* 将@ImportResource指定的配置文件资源缓存在配置类的importedResources中
*/
AnnotationAttributes importResource =
AnnotationConfigUtils.attributesFor(sourceClass.getMetadata(), ImportResource.class); // 配置上的@ImportResource注解对象
if (importResource != null) {
String[] resources = importResource.getStringArray("locations"); // 指定的配置文件路径
Class<? extends BeanDefinitionReader> readerClass = importResource.getClass("reader");
for (String resource : resources) {
String resolvedResource = this.environment.resolveRequiredPlaceholders(resource);
configClass.addImportedResource(resolvedResource, readerClass); // 缓存在配置类的importedResources中
}
}
// ConfigurationClass.java
void addImportedResource(String importedResource, Class<? extends BeanDefinitionReader> readerClass) {
this.importedResources.put(importedResource, readerClass);
}
六 @Bean
// ConfigurationClassParser.java
/**
* @Bean注解的方法
* 将@Bean注解的方法缓存在配置类的beanMethods中
*/
Set<MethodMetadata> beanMethods = retrieveBeanMethodMetadata(sourceClass); // 配置类被@Bean标识的方法
for (MethodMetadata methodMetadata : beanMethods) {
configClass.addBeanMethod(new BeanMethod(methodMetadata, configClass)); // 缓存在配置类的beanMethods中
}
// ConfigurationClass.java
void addBeanMethod(BeanMethod method) {
this.beanMethods.add(method);
}