public static void main(String[] args) throws IOException {
    // @TransactionalService 标注在当前类 TransactionalServiceAnnotationMetadataBootstrap
    String className = TransactionalServiceAnnotationMetadataBootstrap.class.getName();
    // 构建 MetadataReaderFactory 实例
    MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory();
    // 读取 @TransactionService MetadataReader 信息
    MetadataReader metadataReader = metadataReaderFactory.getMetadataReader(className);
    // 读取 @TransactionService AnnotationMetadata 信息
    AnnotationMetadata annotationMetadata = metadataReader.getAnnotationMetadata();

    annotationMetadata.getAnnotationTypes().forEach(annotationType -> {

        Set<String> metaAnnotationTypes = annotationMetadata.getMetaAnnotationTypes(annotationType);

        metaAnnotationTypes.forEach(metaAnnotationType -> {
            System.out.printf("注解 @%s 元标注 @%s\n", annotationType, metaAnnotationType);
        });

    });
}
 

/**
 * Let typeAliasesPackage alias bean support wildcards.
 * 
 * @return
 */
private Class<?>[] getTypeAliases(PathMatchingResourcePatternResolver resolver) throws Exception {
	List<Class<?>> typeAliases = new ArrayList<>();

	// Define metadataReader
	MetadataReaderFactory metadataReaderFty = new CachingMetadataReaderFactory(resolver);

	for (String pkg : typeAliasesPackage.split(",")) {
		// Get location
		String location = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX + ClassUtils.convertClassNameToResourcePath(pkg)
				+ "**/*.class";
		// Get resources.
		Resource[] resources = resolver.getResources(location);
		if (resources != null) {
			for (Resource resource : resources) {
				if (resource.isReadable()) {
					MetadataReader metadataReader = metadataReaderFty.getMetadataReader(resource);
					typeAliases.add(Class.forName(metadataReader.getClassMetadata().getClassName()));
				}
			}
		}
	}

	return typeAliases.toArray(new Class<?>[] {});
}
 

private List<Class<?>> findMangoDaoClasses(String packages) {
    try {
        List<Class<?>> daos = new ArrayList<Class<?>>();
        ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
        MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(resourcePatternResolver);
        for (String locationPattern : getLocationPattern(packages)) {
            Resource[] rs = resourcePatternResolver.getResources(locationPattern);
            for (Resource r : rs) {
                MetadataReader reader = metadataReaderFactory.getMetadataReader(r);
                AnnotationMetadata annotationMD = reader.getAnnotationMetadata();
                if (annotationMD.hasAnnotation(DB.class.getName())) {
                    ClassMetadata clazzMD = reader.getClassMetadata();
                    daos.add(Class.forName(clazzMD.getClassName()));
                }
            }
        }
        return daos;
    } catch (Exception e) {
        throw new IllegalStateException(e.getMessage(), e);
    }
}
 

private void beforeHandlerResource(
		ConcurrentHashMap<String, ConcurrentHashMap<HandlerScope, LinkedList<String>>> handlersMap) {
	try {

		if (!this.packagesList.isEmpty()) {
			for (String pkg : this.packagesList) {
				String pattern = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX
						+ ClassUtils.convertClassNameToResourcePath(pkg)
						+ RESOURCE_PATTERN;
				Resource[] resources = this.resourcePatternResolver
						.getResources(pattern);
				MetadataReaderFactory readerFactory = new CachingMetadataReaderFactory(
						this.resourcePatternResolver);

				onHandlerResource(resources, readerFactory, handlersMap);

			}
		}
	} catch (IOException e) {
		log.fatal("扫描业务处理异常", e);
	}
}
 

public static List<Class> searchAnnotatedClasses(String basePackage, Class<?> annotation)
    throws IOException, ClassNotFoundException {
  ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
  MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(
      resourcePatternResolver);

  List<Class> candidates = new ArrayList<>();
  String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX +
      resolveBasePackage(basePackage) + "/" + "**/*.class";
  Resource[] resources = resourcePatternResolver.getResources(packageSearchPath);
  for (Resource resource : resources) {
    if (resource.isReadable()) {
      MetadataReader metadataReader = metadataReaderFactory.getMetadataReader(resource);
      if (isCandidate(metadataReader, annotation)) {
        candidates.add(Class.forName(metadataReader.getClassMetadata().getClassName()));
      }
    }
  }
  return candidates;
}
 

/**
 * Finds all the classes which have a BeanTag or BeanTags annotation
 *
 * @param basePackage the package to start in
 * @return classes which have BeanTag or BeanTags annotation
 * @throws IOException
 * @throws ClassNotFoundException
 */
protected static List<Class<?>> findTagClasses(String basePackage) throws IOException, ClassNotFoundException {
    ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
    MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(resourcePatternResolver);

    List<Class<?>> classes = new ArrayList<Class<?>>();

    String resolvedBasePackage = ClassUtils.convertClassNameToResourcePath(SystemPropertyUtils.resolvePlaceholders(
            basePackage));
    String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX +
            resolvedBasePackage + "/" + "**/*.class";

    Resource[] resources = resourcePatternResolver.getResources(packageSearchPath);
    for (Resource resource : resources) {
        if (resource.isReadable()) {
            MetadataReader metadataReader = metadataReaderFactory.getMetadataReader(resource);
            if (metadataReader != null && isBeanTag(metadataReader)) {
                classes.add(Class.forName(metadataReader.getClassMetadata().getClassName()));
            }
        }
    }

    return classes;
}
 

private List<Class<?>> findMyTypes(String basePackage) throws IOException, ClassNotFoundException {
	ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
	MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(resourcePatternResolver);

	List<Class<?>> candidates = new ArrayList<>();
	String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX + resolveBasePackage(basePackage)
			+ "/**/*.class";
	Resource[] resources = resourcePatternResolver.getResources(packageSearchPath);
	for (Resource resource : resources) {
		if (resource.isReadable()) {
			MetadataReader metadataReader = metadataReaderFactory.getMetadataReader(resource);
			if (isCandidate(metadataReader)) {
				candidates.add(Class.forName(metadataReader.getClassMetadata().getClassName()));
			}
		}
	}
	return candidates;
}
 

private void resetCachingMetadataReaderFactoryCache() {
    if (getMetadataReaderFactory() instanceof CachingMetadataReaderFactory) {
        Map metadataReaderCache = (Map) ReflectionHelper.getNoException(getMetadataReaderFactory(),
                CachingMetadataReaderFactory.class, "metadataReaderCache");

        if (metadataReaderCache == null)
            metadataReaderCache = (Map) ReflectionHelper.getNoException(getMetadataReaderFactory(),
                    CachingMetadataReaderFactory.class, "classReaderCache");

        if (metadataReaderCache != null) {
            metadataReaderCache.clear();
            LOGGER.debug("Cache cleared: CachingMetadataReaderFactory.clearCache()");
        } else {
            LOGGER.warning("Cache NOT cleared: neither CachingMetadataReaderFactory.metadataReaderCache nor clearCache does not exist.");
        }


    }
}
 

private List<Class<?>> findMangoDaoClasses() {
  try {
    List<Class<?>> daos = new ArrayList<Class<?>>();
    ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
    MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(resourcePatternResolver);
    for (String locationPattern : locationPatterns) {
      Resource[] rs = resourcePatternResolver.getResources(locationPattern);
      for (Resource r : rs) {
        MetadataReader reader = metadataReaderFactory.getMetadataReader(r);
        AnnotationMetadata annotationMD = reader.getAnnotationMetadata();
        if (annotationMD.hasAnnotation(DB.class.getName())) {
          ClassMetadata clazzMD = reader.getClassMetadata();
          daos.add(Class.forName(clazzMD.getClassName()));
        }
      }
    }
    return daos;
  } catch (Exception e) {
    throw new IllegalStateException(e.getMessage(), e);
  }
}
 

/**
 * Finds the beans classes that are annotated with {@code CsvReport} and extends the
 * {@code Report} base class.
 *
 * @param basePackage the package to be scanned.
 * @return the list of classes that match the requirements to be a report bean.
 */
private List<Class<? extends Report>> findReportBeans(String basePackage) throws IOException,
    ClassNotFoundException {
  ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
  MetadataReaderFactory metadataReaderFactory =
      new CachingMetadataReaderFactory(resourcePatternResolver);
  String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX
      + resolveBasePackage(basePackage) + "/" + "**/*.class";
  Resource[] resources = resourcePatternResolver.getResources(packageSearchPath);

  List<Class<? extends Report>> candidates = new ArrayList<Class<? extends Report>>();
  for (Resource resource : resources) {
    addCandidateIfApplicable(resource, metadataReaderFactory, candidates);
  }

  return candidates;
}
 

@Override
public void setResourceLoader(ResourceLoader resourceLoader) {
	Assert.notNull(resourceLoader, "ResourceLoader must not be null");
	this.resourceLoader = resourceLoader;
	if (!this.setMetadataReaderFactoryCalled) {
		this.metadataReaderFactory = new CachingMetadataReaderFactory(resourceLoader);
	}
}
 

@Override
public void setBeanClassLoader(ClassLoader beanClassLoader) {
	this.beanClassLoader = beanClassLoader;
	if (!this.setMetadataReaderFactoryCalled) {
		this.metadataReaderFactory = new CachingMetadataReaderFactory(beanClassLoader);
	}
}
 

/**
 * Return the MetadataReaderFactory used by this component provider.
 */
public final MetadataReaderFactory getMetadataReaderFactory() {
	if (this.metadataReaderFactory == null) {
		this.metadataReaderFactory = new CachingMetadataReaderFactory();
	}
	return this.metadataReaderFactory;
}
 

/**
 * Clear the local metadata cache, if any, removing all cached class metadata.
 */
public void clearCache() {
	if (this.metadataReaderFactory instanceof CachingMetadataReaderFactory) {
		// Clear cache in externally provided MetadataReaderFactory; this is a no-op
		// for a shared cache since it'll be cleared by the ApplicationContext.
		((CachingMetadataReaderFactory) this.metadataReaderFactory).clearCache();
	}
}
 

@Override
protected ConfigurationClassParser newParser() {
	return new ConfigurationClassParser(
			new CachingMetadataReaderFactory(),
			new FailFastProblemReporter(),
			new StandardEnvironment(),
			new DefaultResourceLoader(),
			new AnnotationBeanNameGenerator(),
			new DefaultListableBeanFactory());
}
 

@Override
public void setResourceLoader(ResourceLoader resourceLoader) {
	Assert.notNull(resourceLoader, "ResourceLoader must not be null");
	this.resourceLoader = resourceLoader;
	if (!this.setMetadataReaderFactoryCalled) {
		this.metadataReaderFactory = new CachingMetadataReaderFactory(resourceLoader);
	}
}
 

@Override
public void setBeanClassLoader(ClassLoader beanClassLoader) {
	this.beanClassLoader = beanClassLoader;
	if (!this.setMetadataReaderFactoryCalled) {
		this.metadataReaderFactory = new CachingMetadataReaderFactory(beanClassLoader);
	}
}
 

/**
 * Return the MetadataReaderFactory used by this component provider.
 */
public final MetadataReaderFactory getMetadataReaderFactory() {
	if (this.metadataReaderFactory == null) {
		this.metadataReaderFactory = new CachingMetadataReaderFactory();
	}
	return this.metadataReaderFactory;
}
 

/**
 * Clear the local metadata cache, if any, removing all cached class metadata.
 */
public void clearCache() {
	if (this.metadataReaderFactory instanceof CachingMetadataReaderFactory) {
		// Clear cache in externally provided MetadataReaderFactory; this is a no-op
		// for a shared cache since it'll be cleared by the ApplicationContext.
		((CachingMetadataReaderFactory) this.metadataReaderFactory).clearCache();
	}
}
 

@Override
protected ConfigurationClassParser newParser() {
	return new ConfigurationClassParser(
			new CachingMetadataReaderFactory(),
			new FailFastProblemReporter(),
			new StandardEnvironment(),
			new DefaultResourceLoader(),
			new AnnotationBeanNameGenerator(),
			new DefaultListableBeanFactory());
}
 

@Override
public void setTypeAliasesPackage(String typeAliasesPackage) {
    ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
    MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(resolver);
    typeAliasesPackage = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX +
            ClassUtils.convertClassNameToResourcePath(typeAliasesPackage) + "/" + DEFAULT_RESOURCE_PATTERN;

    //将加载多个绝对匹配的所有Resource
    //将首先通过ClassLoader.getResource("META-INF")加载非模式路径部分
    //然后进行遍历模式匹配
    try {
        List<String> result = new ArrayList<>();
        Resource[] resources = resolver.getResources(typeAliasesPackage);
        if (resources.length > 0) {
            MetadataReader metadataReader = null;
            for (Resource resource : resources) {
                if (resource.isReadable()) {
                    metadataReader = metadataReaderFactory.getMetadataReader(resource);
                    result.add(Class.forName(metadataReader.getClassMetadata().getClassName()).getPackage().getName());
                }
            }
        }
        if (!result.isEmpty()) {
            super.setTypeAliasesPackage(StringUtils.join(result.toArray(), ","));
        } else {
            String msg = String.format("参数typeAliasesPackage:%s，未找到任何包", typeAliasesPackage);
            logger.warn(msg);
        }
    } catch (IOException | ClassNotFoundException e) {
        logger.info(e.getMessage());
    }
}
 

public SimpleConditionService(BeanDefinitionRegistry registry, ConfigurableListableBeanFactory beanFactory,
		Environment environment, ResourceLoader resourceLoader) {
	this.beanFactory = beanFactory;
	this.evaluator = new ConditionEvaluator(registry, environment, resourceLoader);
	this.classLoader = resourceLoader.getClassLoader();
	String metadataFactory = MetadataReaderFactory.class.getName();
	this.metadataReaderFactory = beanFactory.containsSingleton(metadataFactory)
			? (MetadataReaderFactory) beanFactory.getSingleton(metadataFactory)
			: new CachingMetadataReaderFactory(this.classLoader);
}
 

private ConditionService initialize(GenericApplicationContext context) {
	if (!context.getBeanFactory().containsSingleton(ConditionService.class.getName())) {
		if (!context.getBeanFactory().containsSingleton(MetadataReaderFactory.class.getName())) {
			context.getBeanFactory().registerSingleton(MetadataReaderFactory.class.getName(),
					new CachingMetadataReaderFactory(context.getClassLoader()));
		}
		context.getBeanFactory().registerSingleton(ConditionService.class.getName(),
				new SimpleConditionService(context, context.getBeanFactory(), context.getEnvironment(), context));
		context.registerBean(ImportRegistrars.class, () -> new FunctionalInstallerImportRegistrars(context));
	}
	return (ConditionService) context.getBeanFactory().getSingleton(ConditionService.class.getName());
}
 

public FunctionalInstallerImportRegistrars(GenericApplicationContext context) {
	this.context = context;
	String metadataFactory = MetadataReaderFactory.class.getName();
	this.metadataReaderFactory = context.getBeanFactory().containsSingleton(metadataFactory)
			? (MetadataReaderFactory) context.getBeanFactory().getSingleton(metadataFactory)
			: new CachingMetadataReaderFactory(context.getClassLoader());
}
 

@Override
public void initialize(GenericApplicationContext context) {
	if (!ClassUtils.isPresent("org.springframework.boot.test.context.ImportsContextCustomizer",
			context.getClassLoader())
			|| !context.getEnvironment().getProperty("spring.functional.enabled", Boolean.class, true)) {
		// Only used in tests - could move to separate jar
		return;
	}
	ImportRegistrars registrars;
	// TODO: extract this logic and share with FunctionalInstallerListener?
	if (!context.getBeanFactory().containsSingleton(ConditionService.class.getName())) {
		if (!context.getBeanFactory().containsSingleton(MetadataReaderFactory.class.getName())) {
			context.getBeanFactory().registerSingleton(MetadataReaderFactory.class.getName(),
					new CachingMetadataReaderFactory(context.getClassLoader()));
		}
		context.getBeanFactory().registerSingleton(ConditionService.class.getName(),
				new SimpleConditionService(context, context.getBeanFactory(), context.getEnvironment(), context));
		registrars = new FunctionalInstallerImportRegistrars(context);
		context.registerBean(ImportRegistrars.class, () -> registrars);
	}
	else {
		registrars = context.getBean(ImportRegistrars.class.getName(), ImportRegistrars.class);
	}
	for (String name : context.getBeanFactory().getBeanDefinitionNames()) {
		BeanDefinition definition = context.getBeanFactory().getBeanDefinition(name);
		if (definition.getBeanClassName().contains("ImportsContextCustomizer$ImportsConfiguration")) {
			SimpleConditionService.EXCLUDES_ENABLED = true;
			Class<?> testClass = (definition != null) ? (Class<?>) definition.getAttribute("testClass") : null;
			if (testClass != null) {
				Set<Import> merged = AnnotatedElementUtils.findAllMergedAnnotations(testClass, Import.class);
				for (Import ann : merged) {
					for (Class<?> imported : ann.value()) {
						registrars.add(testClass, imported);
					}
				}
			}
		}
	}
}
 

@Override
public void setResourceLoader(ResourceLoader resourceLoader) {
	Assert.notNull(resourceLoader, "ResourceLoader must not be null");
	this.resourceLoader = resourceLoader;
	if (!this.setMetadataReaderFactoryCalled) {
		this.metadataReaderFactory = new CachingMetadataReaderFactory(resourceLoader);
	}
}
 

@Override
public void setBeanClassLoader(ClassLoader beanClassLoader) {
	this.beanClassLoader = beanClassLoader;
	if (!this.setMetadataReaderFactoryCalled) {
		this.metadataReaderFactory = new CachingMetadataReaderFactory(beanClassLoader);
	}
}
 

@Override
public void setBeanClassLoader(ClassLoader beanClassLoader) {
	this.beanClassLoader = beanClassLoader;
	if (!this.setMetadataReaderFactoryCalled) {
		this.metadataReaderFactory = new CachingMetadataReaderFactory(beanClassLoader);
	}
}
 

@Override
protected ConfigurationClassParser newParser() {
	return new ConfigurationClassParser(
			new CachingMetadataReaderFactory(),
			new FailFastProblemReporter(),
			new StandardEnvironment(),
			new DefaultResourceLoader(),
			new AnnotationBeanNameGenerator(),
			new DefaultListableBeanFactory());
}
 

private void scanAndRegisterAnnotationTopics(String[] scanBasePackages){
   	String RESOURCE_PATTERN = "/**/*.class";
   	
   	ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
   	for (String scanBasePackage : scanBasePackages) {
   		logger.info(">>begin scan package [{}] with Annotation[ConsumerHandler] MessageHanlder ",scanBasePackage);
   		try {
               String pattern = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX + ClassUtils.convertClassNameToResourcePath(scanBasePackage)
                       + RESOURCE_PATTERN;
               org.springframework.core.io.Resource[] resources = resourcePatternResolver.getResources(pattern);
               MetadataReaderFactory readerFactory = new CachingMetadataReaderFactory(resourcePatternResolver);
               for (org.springframework.core.io.Resource resource : resources) {
                   if (resource.isReadable()) {
                       MetadataReader reader = readerFactory.getMetadataReader(resource);
                       String className = reader.getClassMetadata().getClassName();
                       Class<?> clazz = Class.forName(className);
                       if(clazz.isAnnotationPresent(ConsumerHandler.class)){
                       	ConsumerHandler annotation = clazz.getAnnotation(ConsumerHandler.class);
                       	MessageHandler hander = (MessageHandler) context.getBean(clazz);
                       	if(!topicHandlers.containsKey(annotation.topic())){                        		
                       		topicHandlers.put(annotation.topic(), hander);
                       		logger.info("register new MessageHandler:{}-{}",annotation.topic(),clazz.getName());
                       	}
                       }
                   }
               }
               logger.info("<<scan package["+scanBasePackage+"] finished!");
           } catch (Exception e) {
           	if(e instanceof org.springframework.beans.factory.NoSuchBeanDefinitionException){
           		throw (org.springframework.beans.factory.NoSuchBeanDefinitionException)e;
           	}
           	logger.error("<<scan package["+scanBasePackage+"] error", e);
           }
	}
   	
}