文章目录
1 EnableAutoConfiguration 注解
在分析整个过程前,首先要确定怎么找到整个加载个程的入口,很明显应从EnableAutoConfiguration这个注解类找突破口,因为整个启动就EnableAutoConfiguration这么一个注解;先观察一下EnableAutoConfiguration类身上有什么
/**
* Enable auto-configuration of the Spring Application Context, attempting to guess and
* configure beans that you are likely to need. Auto-configuration classes are usually
上面是EnableAutoConfiguration上摘了一个段解释,该类用于开启spring容器自动配置
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@AutoConfigurationPackage
@Import(EnableAutoConfigurationImportSelector.class)
public @interface EnableAutoConfiguration {
String ENABLED_OVERRIDE_PROPERTY = "spring.boot.enableautoconfiguration";
/**
* Exclude specific auto-configuration classes such that they will never be applied.
* @return the classes to exclude
*/
Class<?>[] exclude() default {};
/**
* Exclude specific auto-configuration class names such that they will never be
* applied.
* @return the class names to exclude
* @since 1.3.0
*/
String[] excludeName() default {};
}
在该注解上发现有这么一个类EnableAutoConfigurationImportSelector,看源码前根据类型可以猜得出该类是用于自动配置引入选择,那又回暂时回到EnableAutoConfiguration注解上,发现有两方法再据上面的注释,EnableAutoConfigurationImportSelector 引入配置时会将该两方法里值配置排了掉;
/**
* {@link DeferredImportSelector} to handle {@link EnableAutoConfiguration
* auto-configuration}. This class can also be subclassed if a custom variant of
* {@link EnableAutoConfiguration @EnableAutoConfiguration}. is needed.
*
* @author Phillip Webb
* @author Andy Wilkinson
* @author Stephane Nicoll
* @since 1.3.0
* @see EnableAutoConfiguration
*/
public class EnableAutoConfigurationImportSelector
implements DeferredImportSelector, BeanClassLoaderAware, ResourceLoaderAware,
BeanFactoryAware, EnvironmentAware, Ordered {
private static final String[] NO_IMPORTS = {};
private ConfigurableListableBeanFactory beanFactory;
private Environment environment;
private ClassLoader beanClassLoader;
private ResourceLoader resourceLoader;
//配置开始处理的地方
@Override
public String[] selectImports(AnnotationMetadata metadata) {
if (!isEnabled(metadata)) {
return NO_IMPORTS;
}
try {
AnnotationAttributes attributes = getAttributes(metadata);
List<String> configurations = getCandidateConfigurations(metadata,
再来一张整体的调用链路
2 更详细的调用链路分析
//该方在applicationcontext.refresh中调用
public static void invokeBeanFactoryPostProcessors(
ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {
// Invoke BeanDefinitionRegistryPostProcessors first, if any.
Set<String> processedBeans = new HashSet<String>();
if (beanFactory instanceof BeanDefinitionRegistry) {
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
List<BeanFactoryPostProcessor> regularPostProcessors = new LinkedList<BeanFactoryPostProcessor>();
List<BeanDefinitionRegistryPostProcessor> registryPostProcessors =
new LinkedList<BeanDefinitionRegistryPostProcessor>();
for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
BeanDefinitionRegistryPostProcessor registryPostProcessor =
(BeanDefinitionRegistryPostProcessor) postProcessor;
registryPostProcessor.postProcessBeanDefinitionRegistry(registry);
registryPostProcessors.add(registryPostProcessor);
} else {
regularPostProcessors.add(postProcessor);
}
}
// Do not initialize FactoryBeans here: We need to leave all regular beans
// uninitialized to let the bean factory post-processors apply to them!
// Separate between BeanDefinitionRegistryPostProcessors that implement
// PriorityOrdered, Ordered, and the rest.
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
//找出实现PriorityOrdered(优先接口)接口的BeanDefinitonRegistry
List<BeanDefinitionRegistryPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanDefinitionRegistryPostProcessor>();
for (String ppName : postProcessorNames) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
}
}
sortPostProcessors(beanFactory, priorityOrderedPostProcessors);
registryPostProcessors.addAll(priorityOrderedPostProcessors);
//ConfigurationClassPostProcessor 实现了PriorityOrdered接口,将会被优先调用
invokeBeanDefinitionRegistryPostProcessors(priorityOrderedPostProcessors, registry);
// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
List<BeanDefinitionRegistryPostProcessor> orderedPostProcessors = new ArrayList<BeanDefinitionRegistryPostProcessor>();
for (String ppName : postProcessorNames) {
if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
}
}
sortPostProcessors(beanFactory, orderedPostProcessors);
registryPostProcessors.addAll(orderedPostProcessors);
invokeBeanDefinitionRegistryPostProcessors(orderedPostProcessors, registry);
}
/**
* Invoke the given BeanDefinitionRegistryPostProcessor beans.
*/
private static void invokeBeanDefinitionRegistryPostProcessors(
Collection<? extends BeanDefinitionRegistryPostProcessor> postProcessors, BeanDefinitionRegistry registry) {
for (BeanDefinitionRegistryPostProcessor postProcessor : postProcessors) {
postProcessor.postProcessBeanDefinitionRegistry(registry);
}
}
3 配置类ConfigurationClassPostProcessor调用处理过程
@Override
public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) {
//把registry(实质是DefaultListBeanFactory),最终目的是把配置里的类封成对应的beandefination并注册到该beanfactory里
//处理配置文件前的一些准备
RootBeanDefinition iabpp = new RootBeanDefinition(ImportAwareBeanPostProcessor.class);
iabpp.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
registry.registerBeanDefinition(IMPORT_AWARE_PROCESSOR_BEAN_NAME, iabpp);
RootBeanDefinition ecbpp = new RootBeanDefinition(EnhancedConfigurationBeanPostProcessor.class);
ecbpp.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
registry.registerBeanDefinition(ENHANCED_CONFIGURATION_PROCESSOR_BEAN_NAME, ecbpp);
int registryId = System.identityHashCode(registry);
if (this.registriesPostProcessed.contains(registryId)) {
throw new IllegalStateException(
"postProcessBeanDefinitionRegistry already called on this post-processor against " + registry);
}
if (this.factoriesPostProcessed.contains(registryId)) {
throw new IllegalStateException(
"postProcessBeanFactory already called on this post-processor against " + registry);
}
this.registriesPostProcessed.add(registryId);
//开始处理配置文件了
processConfigBeanDefinitions(registry);
}
/**
* Build and validate a configuration model based on the registry of
* {@link Configuration} classes.
*/
public void processConfigBeanDefinitions(BeanDefinitionRegistry registry) {
List<BeanDefinitionHolder> configCandidates = new ArrayList<BeanDefinitionHolder>();
//获取所有注册到beanfactory里的beanNames(这里并非所有的beandefinition已加载到容器了)
String[] candidateNames = registry.getBeanDefinitionNames();
//找出被@Configuration,@Import ,@EnableAutoConfiguration(开始的疑问这上在这里利到的) 注解的类
for (String beanName : candidateNames) {
BeanDefinition beanDef = registry.getBeanDefinition(beanName);
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)) {
//如果是配置类,将添加到集合,再进一步处理
configCandidates.add(new BeanDefinitionHolder(beanDef, beanName));
}
}
// Return immediately if no @Configuration classes were found
if (configCandidates.isEmpty()) {
return;
}
// Sort by previously determined @Order value, if applicable
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;
}
});
// Detect any custom bean name generation strategy supplied through the enclosing application context
SingletonBeanRegistry singletonRegistry = null;
if (registry instanceof SingletonBeanRegistry) {
singletonRegistry = (SingletonBeanRegistry) registry;
if (!this.localBeanNameGeneratorSet && singletonRegistry.containsSingleton(CONFIGURATION_BEAN_NAME_GENERATOR)) {
BeanNameGenerator generator = (BeanNameGenerator) singletonRegistry.getSingleton(CONFIGURATION_BEAN_NAME_GENERATOR);
this.componentScanBeanNameGenerator = generator;
this.importBeanNameGenerator = generator;
}
}
// Parse each @Configuration class
//配置类解释器,this.componentScanBeanNameGenerator: @CompenmentScane注解处理器
ConfigurationClassParser parser = new ConfigurationClassParser(
this.metadataReaderFactory, this.problemReporter, this.environment,
this.resourceLoader, this.componentScanBeanNameGenerator, registry);
Set<BeanDefinitionHolder> candidates = new LinkedHashSet<BeanDefinitionHolder>(configCandidates);
Set<ConfigurationClass> alreadyParsed = new HashSet<ConfigurationClass>(configCandidates.size());
do {
//开始解释这个配置类
parser.parse(candidates);
parser.validate();
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());
}
this.reader.loadBeanDefinitions(configClasses);
alreadyParsed.addAll(configClasses);
candidates.clear();
if (registry.getBeanDefinitionCount() > candidateNames.length) {
String[] newCandidateNames = registry.getBeanDefinitionNames();
Set<String> oldCandidateNames = new HashSet<String>(Arrays.asList(candidateNames));
Set<String> alreadyParsedClasses = new HashSet<String>();
for (ConfigurationClass configurationClass : alreadyParsed) {
alreadyParsedClasses.add(configurationClass.getMetadata().getClassName());
}//判断新添加的Beandefinition里有没有ConfigurationClass并且是没有alreadyParseClass里的
for (String candidateName : newCandidateNames) {
if (!oldCandidateNames.contains(candidateName)) {
BeanDefinition beanDef = registry.getBeanDefinition(candidateName);
if (ConfigurationClassUtils.checkConfigurationClassCandidate(beanDef, this.metadataReaderFactory) &&
!alreadyParsedClasses.contains(beanDef.getBeanClassName())) {
candidates.add(new BeanDefinitionHolder(beanDef, candidateName));
}
}
}
candidateNames = newCandidateNames;
}
}
while (!candidates.isEmpty());
// Register the ImportRegistry as a bean in order to support ImportAware @Configuration classes
if (singletonRegistry != null) {
if (!singletonRegistry.containsSingleton(IMPORT_REGISTRY_BEAN_NAME)) {
singletonRegistry.registerSingleton(IMPORT_REGISTRY_BEAN_NAME, parser.getImportRegistry());
}
}
if (this.metadataReaderFactory instanceof CachingMetadataReaderFactory) {
((CachingMetadataReaderFactory) this.metadataReaderFactory).clearCache();
}
}
到此为此,需然一直跟的是主线,仅仅只知道EnableAutoConfiguration被解释到,但还没看到具实现;在看具体实现之前,先看下上面那段代码的处理结果:
据上面结果,可以推断spring-boot自动配置的具体实现就是在ConfigurationClassParser.parse()里面
public void parse(Set<BeanDefinitionHolder> configCandidates) {
this.deferredImportSelectors = new LinkedList<ConfigurationClassParser.DeferredImportSelectorHolder>();
for (BeanDefinitionHolder holder : configCandidates) {
BeanDefinition bd = holder.getBeanDefinition();
try {
//处理配置类上@ComponentScan(当前分析的例子MyBootApplication)
// 指定包下被@Component及其它子类标注的类,并老封装成beanDefinition
if (bd instanceof AnnotatedBeanDefinition) {//getMetadata获取身上的元数据(注解这个信息)
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);
}
}
//这里才开始处理spring-factories里的配置信息
processDeferredImportSelectors();
}
上图看看下执行结果
private void processDeferredImportSelectors() {
List<ConfigurationClassParser.DeferredImportSelectorHolder> deferredImports = this.deferredImportSelectors;
this.deferredImportSelectors = null;
Collections.sort(deferredImports, DEFERRED_IMPORT_COMPARATOR);
for (ConfigurationClassParser.DeferredImportSelectorHolder deferredImport : deferredImports) {
ConfigurationClass configClass = deferredImport.getConfigurationClass();
try {
//读取spring-factories里EnableAutoConfiguration 的配置
String[] imports = deferredImport.getImportSelector().selectImports(configClass.getMetadata());
processImports(configClass, asSourceClass(configClass), asSourceClasses(imports), false);
}
catch (BeanDefinitionStoreException ex) {
throw ex;
}
catch (Throwable ex) {
throw new BeanDefinitionStoreException("Failed to process import candidates for configuration class [" +
configClass.getMetadata().getClassName() + "]", ex);
}
}
}
4 spring-factories 自动配置的类
# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\
org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration,\
org.springframework.boot.autoconfigure.MessageSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration,\
org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration,\
org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,\
org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration,\
org.springframework.boot.autoconfigure.cloud.CloudAutoConfiguration,\
org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,\
org.springframework.boot.autoconfigure.couchbase.CouchbaseAutoConfiguration,\
org.springframework.boot.autoconfigure.dao.PersistenceExceptionTranslationAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.solr.SolrRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.rest.RepositoryRestMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.data.web.SpringDataWebAutoConfiguration,\
org.springframework.boot.autoconfigure.elasticsearch.jest.JestAutoConfiguration,\
org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration,\
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration,\
org.springframework.boot.autoconfigure.h2.H2ConsoleAutoConfiguration,\
org.springframework.boot.autoconfigure.hateoas.HypermediaAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastJpaDependencyAutoConfiguration,\
org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration,\
org.springframework.boot.autoconfigure.integration.IntegrationAutoConfiguration,\
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.XADataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JmsAutoConfiguration,\
org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JndiConnectionFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.activemq.ActiveMQAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.artemis.ArtemisAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.hornetq.HornetQAutoConfiguration,\
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration,\
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration,\
org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration,\
org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderValidatorAutoConfiguration,\
org.springframework.boot.autoconfigure.mobile.DeviceResolverAutoConfiguration,\
org.springframework.boot.autoconfigure.mobile.DeviceDelegatingViewResolverAutoConfiguration,\
org.springframework.boot.autoconfigure.mobile.SitePreferenceAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration,\
org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration,\
org.springframework.boot.autoconfigure.reactor.ReactorAutoConfiguration,\
org.springframework.boot.autoconfigure.security.SecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.SecurityFilterAutoConfiguration,\
org.springframework.boot.autoconfigure.security.FallbackWebSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.OAuth2AutoConfiguration,\
org.springframework.boot.autoconfigure.sendgrid.SendGridAutoConfiguration,\
org.springframework.boot.autoconfigure.session.SessionAutoConfiguration,\
org.springframework.boot.autoconfigure.social.SocialWebAutoConfiguration,\
org.springframework.boot.autoconfigure.social.FacebookAutoConfiguration,\
org.springframework.boot.autoconfigure.social.LinkedInAutoConfiguration,\
org.springframework.boot.autoconfigure.social.TwitterAutoConfiguration,\
org.springframework.boot.autoconfigure.solr.SolrAutoConfiguration,\
org.springframework.boot.autoconfigure.velocity.VelocityAutoConfiguration,\
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.jta.JtaAutoConfiguration,\
org.springframework.boot.autoconfigure.web.DispatcherServletAutoConfiguration,\
org.springframework.boot.autoconfigure.web.EmbeddedServletContainerAutoConfiguration,\
org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.web.HttpEncodingAutoConfiguration,\
org.springframework.boot.autoconfigure.web.HttpMessageConvertersAutoConfiguration,\
org.springframework.boot.autoconfigure.web.MultipartAutoConfiguration,\
org.springframework.boot.autoconfigure.web.ServerPropertiesAutoConfiguration,\
org.springframework.boot.autoconfigure.web.WebClientAutoConfiguration,\
org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.WebSocketAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.WebSocketMessagingAutoConfiguration,\
org.springframework.boot.autoconfigure.webservices.WebServicesAutoConfiguration
5 配置类具体导入
EnableAutoConfigurationImportSelector.selectImports()
@Override
public String[] selectImports(AnnotationMetadata metadata) {
if (!isEnabled(metadata)) {
return NO_IMPORTS;
}
try {
//获取注解信息
AnnotationAttributes attributes = getAttributes(metadata);
List<String> configurations = getCandidateConfigurations(metadata,
attributes);//
configurations = removeDuplicates(configurations);
Set<String> exclusions = getExclusions(metadata, attributes);
configurations.removeAll(exclusions);//排除不自动配置的类
configurations = sort(configurations);
recordWithConditionEvaluationReport(configurations, exclusions);
return configurations.toArray(new String[configurations.size()]);
}
catch (IOException ex) {
throw new IllegalStateException(ex);
}
}
protected List<String> getCandidateConfigurations(AnnotationMetadata metadata,
AnnotationAttributes attributes) {
//熟悉的代码,以org.springframework.boot.autoconfigure.EnableAutoConfiguration 为key,加载所有配置值
List<String> configurations = SpringFactoriesLoader.loadFactoryNames(
getSpringFactoriesLoaderFactoryClass(), getBeanClassLoader());
Assert.notEmpty(configurations,
"No auto configuration classes found in META-INF/spring.factories. If you "
+ "are using a custom packaging, make sure that file is correct.");
return configurations;
}
到此为止,基本可以看到spring-boot自动整个过程,至于EnableAutoConfiguration配置文件值是怎么使用的?,
下面@位置可以看到程序获取EnableAutoConfiguration身上的EnableAutoConfigurationImportSelector,并利其去解释配置信息
//将获取到的配置名简单的封装成SourceClass(importCandidates),然后进一步处理
private void processImports(ConfigurationClass configClass, ConfigurationClassParser.SourceClass currentSourceClass,
Collection<ConfigurationClassParser.SourceClass> importCandidates, boolean checkForCircularImports) throws IOException {
if (importCandidates.isEmpty()) {
return;
}
if (checkForCircularImports && isChainedImportOnStack(configClass)) {
this.problemReporter.error(new ConfigurationClassParser.CircularImportProblem(configClass, this.importStack));
}
else {
this.importStack.push(configClass);
try {
for (ConfigurationClassParser.SourceClass candidate : importCandidates) {
if (candidate.isAssignable(ImportSelector.class)) {//判断是否为导入选择器
// Candidate class is an ImportSelector -> delegate to it to determine imports
Class<?> candidateClass = candidate.loadClass();
ImportSelector selector = BeanUtils.instantiateClass(candidateClass, ImportSelector.class);
invokeAwareMethods(selector);
if (this.deferredImportSelectors != null && selector instanceof DeferredImportSelector) {
this.deferredImportSelectors.add(//@获取注解上的selector,如EnableAutoConfiguration,上的
EnableAutoConfigurationImportSelector
new ConfigurationClassParser.DeferredImportSelectorHolder(configClass, (DeferredImportSelector) selector));
}
else {
//继续获取导入配置
String[] importClassNames = selector.selectImports(currentSourceClass.getMetadata());
Collection<ConfigurationClassParser.SourceClass> importSourceClasses = asSourceClasses(importClassNames);
processImports(configClass, currentSourceClass, importSourceClasses, false);
}
}
else if (candidate.isAssignable(ImportBeanDefinitionRegistrar.class)) {
// Candidate class is an ImportBeanDefinitionRegistrar ->
// delegate to it to register additional bean definitions
Class<?> candidateClass = candidate.loadClass();
ImportBeanDefinitionRegistrar registrar =
BeanUtils.instantiateClass(candidateClass, ImportBeanDefinitionRegistrar.class);
invokeAwareMethods(registrar);
configClass.addImportBeanDefinitionRegistrar(registrar, currentSourceClass.getMetadata());
}
else {
// Candidate class not an ImportSelector or ImportBeanDefinitionRegistrar ->
// process it as an @Configuration class
this.importStack.registerImport(
currentSourceClass.getMetadata(), candidate.getMetadata().getClassName());
//以上都不是的情况下,开始处理该配置类
processConfigurationClass(candidate.asConfigClass(configClass));
}
}
}
catch (BeanDefinitionStoreException ex) {
throw ex;
}
catch (Throwable ex) {
throw new BeanDefinitionStoreException("Failed to process import candidates for configuration class [" +
configClass.getMetadata().getClassName() + "]", ex);
}
finally {
this.importStack.pop();
}
}
protected void processConfigurationClass(ConfigurationClass configClass) throws IOException {
if (this.conditionEvaluator.shouldSkip(configClass.getMetadata(), ConfigurationCondition.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();
}
}
}
}
// Recursively process the configuration class and its superclass hierarchy.
ConfigurationClassParser.SourceClass sourceClass = asSourceClass(configClass);
do {
sourceClass = doProcessConfigurationClass(configClass, sourceClass);
}
while (sourceClass != null);
//最终返回被spring容器管理的配置类
this.configurationClasses.put(configClass, configClass);
}