spring版本为5.0.11
ConfigurationClassPostProcessor对配置类的解析
public void parse(Set<BeanDefinitionHolder> configCandidates) { //List<ConfigurationClassParser.DeferredImportSelectorHolder> deferredImportSelectors 进行初始化 this.deferredImportSelectors = new LinkedList(); Iterator var2 = configCandidates.iterator(); //循环遍历需要处理的配置类 while(var2.hasNext()) { BeanDefinitionHolder holder = (BeanDefinitionHolder)var2.next(); BeanDefinition bd = holder.getBeanDefinition(); //根据BeanDefinition实例判断调用哪个，其实最后还是调用 //核心方法：processConfigurationClass(ConfigurationClass configClass) 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 { this.parse(bd.getBeanClassName(), holder.getBeanName()); } } catch (BeanDefinitionStoreException var6) { throw var6; } catch (Throwable var7) { throw new BeanDefinitionStoreException("Failed to parse configuration class [" + bd.getBeanClassName() + "]", var7); } } //字面理解：处理延迟导入的javabean //parse方法，把被处理的类实现DeferredImportSelector接口，加入deferredImportSelectors集合中， //处理deferredImportSelectors集合种类 this.processDeferredImportSelectors(); }
parse调用核心方法processConfigurationClass(ConfigurationClass configClass)解析
protected void processConfigurationClass(ConfigurationClass configClass) throws IOException { //检查当前解析的配置bean是否包含Conditional注解，如果不包含则不需要跳过 // 如果包含了则进行match方法得到匹配结果，如果是符合的并且设置的配置解析策略是解析阶段不需要调过 if (!this.conditionEvaluator.shouldSkip(configClass.getMetadata(), ConfigurationPhase.PARSE_CONFIGURATION)) { //在这里处理Configuration重复import //如果同一个配置类被处理两次，两次都属于被import的则合并导入类，返回。如果配置类不是被导入的，则移除旧使用新的配置类 ConfigurationClass existingClass = (ConfigurationClass)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; } // 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. ConfigurationClassParser.SourceClass sourceClass = this.asSourceClass(configClass); //递归解析 do { sourceClass = this.doProcessConfigurationClass(configClass, sourceClass); } while(sourceClass != null); // 添加到ConfigurationClassParser的configurationClasses中 this.configurationClasses.put(configClass, configClass); } }
递归解析，调用doProcessConfigurationClass方法，终于到了解析的地方！！
总结一下：
1.处理内部类
2.处理@PropertySource注解
3.处理@ComponentScan注解
4.处理@Import注解
5.处理@ImportResource注解
6.处理@Bean修饰的方法
7.处理接口定义的方法
8.处理父类
protected final ConfigurationClassParser.SourceClass doProcessConfigurationClass(ConfigurationClass configClass, ConfigurationClassParser.SourceClass sourceClass) throws IOException { // Recursively process any member (nested) classes first 处理内部类 this.processMemberClasses(configClass, sourceClass); // Process any @PropertySource annotations // 处理@PropertySource注解 Iterator var3 = AnnotationConfigUtils.attributesForRepeatable(sourceClass.getMetadata(), PropertySources.class, PropertySource.class).iterator(); AnnotationAttributes importResource; while(var3.hasNext()) { importResource = (AnnotationAttributes)var3.next(); if (this.environment instanceof ConfigurableEnvironment) { this.processPropertySource(importResource); } else { this.logger.warn("Ignoring @PropertySource annotation on [" + sourceClass.getMetadata().getClassName() + "]. Reason: Environment must implement ConfigurableEnvironment"); } } //// Process any @ComponentScan annotations // 处理@ComponentScan注解 Set<AnnotationAttributes> componentScans = AnnotationConfigUtils.attributesForRepeatable(sourceClass.getMetadata(), ComponentScans.class, ComponentScan.class); if (!componentScans.isEmpty() && !this.conditionEvaluator.shouldSkip(sourceClass.getMetadata(), ConfigurationPhase.REGISTER_BEAN)) { Iterator var13 = componentScans.iterator(); // The config class is annotated with @ComponentScan -> perform the scan immediately //扫描 while(var13.hasNext()) { AnnotationAttributes componentScan = (AnnotationAttributes)var13.next(); Set<BeanDefinitionHolder> scannedBeanDefinitions = this.componentScanParser.parse(componentScan, sourceClass.getMetadata().getClassName()); Iterator var7 = scannedBeanDefinitions.iterator(); // Check the set of scanned definitions for any further config classes and parse recursively if necessary //遍历扫描到的配置类进行递归解析 while(var7.hasNext()) { BeanDefinitionHolder holder = (BeanDefinitionHolder)var7.next(); BeanDefinition bdCand = holder.getBeanDefinition().getOriginatingBeanDefinition(); if (bdCand == null) { bdCand = holder.getBeanDefinition(); } if (ConfigurationClassUtils.checkConfigurationClassCandidate(bdCand, this.metadataReaderFactory)) { this.parse(bdCand.getBeanClassName(), holder.getBeanName()); } } } } // Process any @Import annotations // 处理@Import注解 this.processImports(configClass, sourceClass, this.getImports(sourceClass), true); // Process any @ImportResource annotations. // 处理@ImportResource 注解 importResource = AnnotationConfigUtils.attributesFor(sourceClass.getMetadata(), ImportResource.class); if (importResource != null) { String[] resources = importResource.getStringArray("locations"); Class<? extends BeanDefinitionReader> readerClass = importResource.getClass("reader"); String[] var19 = resources; int var21 = resources.length; // 遍历配置的locations,加入到configClass 中的ImportedResource for(int var22 = 0; var22 < var21; ++var22) { String resource = var19[var22]; String resolvedResource = this.environment.resolveRequiredPlaceholders(resource); configClass.addImportedResource(resolvedResource, readerClass); } } // Process individual @Bean methods // 处理@Bean修饰的方法 Set<MethodMetadata> beanMethods = this.retrieveBeanMethodMetadata(sourceClass); Iterator var17 = beanMethods.iterator(); while(var17.hasNext()) { MethodMetadata methodMetadata = (MethodMetadata)var17.next(); configClass.addBeanMethod(new BeanMethod(methodMetadata, configClass)); } // Process default methods on interfaces // 处理接口定义的方法 this.processInterfaces(configClass, sourceClass); 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; }
1.处理内部类（递归解析）
private void processMemberClasses(ConfigurationClass configClass, ConfigurationClassParser.SourceClass sourceClass) throws IOException { //读取配置类中所有成员类 Collection<ConfigurationClassParser.SourceClass> memberClasses = sourceClass.getMemberClasses(); if (!memberClasses.isEmpty()) { List<ConfigurationClassParser.SourceClass> candidates = new ArrayList(memberClasses.size()); Iterator var5 = memberClasses.iterator(); //过滤出配置类 ConfigurationClassParser.SourceClass candidate; while(var5.hasNext()) { candidate = (ConfigurationClassParser.SourceClass)var5.next(); if (ConfigurationClassUtils.isConfigurationCandidate(candidate.getMetadata()) && !candidate.getMetadata().getClassName().equals(configClass.getMetadata().getClassName())) { candidates.add(candidate); } } //根据Order进行排序 OrderComparator.sort(candidates); var5 = candidates.iterator(); //遍历 while(var5.hasNext()) { candidate = (ConfigurationClassParser.SourceClass)var5.next(); //1）出现配置类循环导入,直接报错 if (this.importStack.contains(configClass)) { this.problemReporter.error(new ConfigurationClassParser.CircularImportProblem(configClass, this.importStack)); } else { //将配置类入栈 this.importStack.push(configClass); try { //处理配置类 this.processConfigurationClass(candidate.asConfigClass(configClass)); } finally { //解析完出栈 this.importStack.pop(); } } } } }
2.处理@PropertySource注解
如果配置类上有@PropertySource注解，则解析加载properties文件，并将属性添加到Spring上下文中。
this.addPropertySource(factory.createPropertySource(name, new EncodedResource(resource, encoding)));
3.处理@ComponentScan注解
获取配置类上的@ComponentScan注解，判断是否需要跳过。循环所有的ComponentScan，立即执行扫描。
// Process any @ComponentScan annotations Set<AnnotationAttributes> componentScans = AnnotationConfigUtils.attributesForRepeatable(sourceClass.getMetadata(), ComponentScans.class, ComponentScan.class); if (!componentScans.isEmpty() && !this.conditionEvaluator.shouldSkip(sourceClass.getMetadata(), ConfigurationPhase.REGISTER_BEAN)) { Iterator var13 = componentScans.iterator(); while(var13.hasNext()) { AnnotationAttributes componentScan = (AnnotationAttributes)var13.next(); // The config class is annotated with @ComponentScan -> perform the scan immediately Set<BeanDefinitionHolder> scannedBeanDefinitions = this.componentScanParser.parse(componentScan, sourceClass.getMetadata().getClassName()); Iterator var7 = scannedBeanDefinitions.iterator(); // Check the set of scanned definitions for any further config classes and parse recursively if needed while(var7.hasNext()) { BeanDefinitionHolder holder = (BeanDefinitionHolder)var7.next(); BeanDefinition bdCand = holder.getBeanDefinition().getOriginatingBeanDefinition(); if (bdCand == null) { bdCand = holder.getBeanDefinition(); } //检验扫描获得的BeanDefinition中是否有配置类，如果有配置类,这里的配置类包括FullConfigurationClass和LiteConfigurationClass。 //（也就是说只要有@Configuration、@Component、@ComponentScan、@Import、@ImportResource和@Bean中的其中一个注解），则递归调用parse方法，进行解析。 if (ConfigurationClassUtils.checkConfigurationClassCandidate(bdCand, this.metadataReaderFactory)) { this.parse(bdCand.getBeanClassName(), holder.getBeanName()); } } } }
4.处理@Import注解
this.processImports(configClass, sourceClass, this.getImports(sourceClass), true);
processImports方法负责对@Import注解进行解析。configClass是配置类，sourceClass又是通过configClass创建的，getImports(sourceClass)从sourceClass获取所有的@Import注解信息
private void processImports(ConfigurationClass configClass, ConfigurationClassParser.SourceClass currentSourceClass, Collection<ConfigurationClassParser.SourceClass> importCandidates, boolean checkForCircularImports) { if (!importCandidates.isEmpty()) { //循环导入直接报错 if (checkForCircularImports && this.isChainedImportOnStack(configClass)) { this.problemReporter.error(new ConfigurationClassParser.CircularImportProblem(configClass, this.importStack)); } else { //推入栈 this.importStack.push(configClass); try { Iterator var5 = importCandidates.iterator(); //循环遍历 while(true) { while(true) { while(var5.hasNext()) { ConfigurationClassParser.SourceClass candidate = (ConfigurationClassParser.SourceClass)var5.next(); Class candidateClass; //对import的内容进行分类 // import导入实现ImportSelector接口的类 if (candidate.isAssignable(ImportSelector.class)) { // Candidate class is an ImportSelector -> delegate to it to determine imports candidateClass = candidate.loadClass(); // 反射创建这个类的实例对象 ImportSelector selector = (ImportSelector)BeanUtils.instantiateClass(candidateClass, ImportSelector.class); //是否有实现相关Aware接口,如果有,这调用相关方法 ParserStrategyUtils.invokeAwareMethods(selector, this.environment, this.resourceLoader, this.registry); // 延迟加载的ImportSelector if (this.deferredImportSelectors != null && selector instanceof DeferredImportSelector) { // 延迟加载的ImportSelector先放到List中,延迟加载 this.deferredImportSelectors.add(new ConfigurationClassParser.DeferredImportSelectorHolder(configClass, (DeferredImportSelector)selector)); } else { // 普通的ImportSelector ,执行其selectImports方法,获取需要导入的类的全限定类名数组 String[] importClassNames = selector.selectImports(currentSourceClass.getMetadata()); Collection<ConfigurationClassParser.SourceClass> importSourceClasses = this.asSourceClasses(importClassNames); // 递归调用 this.processImports(configClass, currentSourceClass, importSourceClasses, false); } // 是否为ImportBeanDefinitionRegistrar } else if (candidate.isAssignable(ImportBeanDefinitionRegistrar.class)) { // Candidate class is an ImportBeanDefinitionRegistrar -> // delegate to it to register additional bean definitions candidateClass = candidate.loadClass(); ImportBeanDefinitionRegistrar registrar = (ImportBeanDefinitionRegistrar)BeanUtils.instantiateClass(candidateClass, ImportBeanDefinitionRegistrar.class); ParserStrategyUtils.invokeAwareMethods(registrar, this.environment, this.resourceLoader, this.registry); // 添加到成员变量 configClass.addImportBeanDefinitionRegistrar(registrar, currentSourceClass.getMetadata()); } else { // Candidate class not an ImportSelector or ImportBeanDefinitionRegistrar -> // process it as an @Configuration class // 普通 @Configuration class this.importStack.registerImport(currentSourceClass.getMetadata(), candidate.getMetadata().getClassName()); // 解析导入的@Configuration class this.processConfigurationClass(candidate.asConfigClass(configClass)); } } return; } } } catch (BeanDefinitionStoreException var15) { throw var15; } catch (Throwable var16) { throw new BeanDefinitionStoreException("Failed to process import candidates for configuration class [" + configClass.getMetadata().getClassName() + "]", var16); } finally { this.importStack.pop(); } } } }
5.处理@ImportResource注解
@ImportResource注解可以导入xml配置文件。
// Process any @ImportResource annotations importResource = AnnotationConfigUtils.attributesFor(sourceClass.getMetadata(), ImportResource.class); if (importResource != null) { String[] resources = importResource.getStringArray("locations"); Class<? extends BeanDefinitionReader> readerClass = importResource.getClass("reader"); String[] var19 = resources; int var21 = resources.length; for(int var22 = 0; var22 < var21; ++var22) { String resource = var19[var22]; String resolvedResource = this.environment.resolveRequiredPlaceholders(resource); //把配置项提取出来，跟reader一起放入configClass的map中， //接下来会在ConfigurationClassPostProcessor类中processConfigBeanDefinitions方法中，解析完， //this.reader.loadBeanDefinitions(configClasses)这方法会对@import处理（对ImportBeanDefinitionRegistrars的处理） configClass.addImportedResource(resolvedResource, readerClass); } }
6.处理@Bean修饰的方法
将@Bean方法转化为BeanMethod对象
Set<MethodMetadata> beanMethods = this.retrieveBeanMethodMetadata(sourceClass); Iterator var17 = beanMethods.iterator(); while(var17.hasNext()) { MethodMetadata methodMetadata = (MethodMetadata)var17.next(); //添加到configClass的beanMethods集合中，接下来，会在this.reader.loadBeanDefinitions(configClasses)这方法 //得到处理 configClass.addBeanMethod(new BeanMethod(methodMetadata, configClass)); }
7.处理接口定义的方法
this.processInterfaces(configClass, sourceClass);
8.处理父类
if (sourceClass.getMetadata().hasSuperClass()) { String superclass = sourceClass.getMetadata().getSuperClassName(); if (superclass != null && !superclass.startsWith("java") && !this.knownSuperclasses.containsKey(superclass)) { this.knownSuperclasses.put(superclass, configClass); return sourceClass.getSuperClass(); } }
如果有父类则返回父类Class对象，继续调用该方法。直到返回null，外层循环结束。
do { sourceClass = doProcessConfigurationClass(configClass, sourceClass); } while (sourceClass != null);