springboot源码分析-自动装配

1.概述

springboot是用main方法来启动服务的，mian方法都加有 SpringBootApplication这个注解，这个注解是springboot自动装配的实现

首先看SpringBootApplication这个注解的源码


package org.springframework.boot.autoconfigure;

import java.lang.annotation.documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.springframework.boot.SpringBootConfiguration;
import org.springframework.boot.context.TypeExcludeFilter;
import org.springframework.boot.context.properties.ConfigurationPropertiesScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScan.Filter;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.core.annotation.AliasFor;
import org.springframework.data.repository.Repository;


@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@documented
@Inherited //表示能从子类的注解中获取到父类的注解属性
@SpringBootConfiguration //注解继承了Configuration注解并且增加了开启代理的配置
@EnableAutoConfiguration //自动装配的主要实现
@ComponentScan(excludeFilters = {@Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),
		@Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class)}) //扫包
@ConfigurationPropertiesScan //属性文件内容自动填充bean
public @interface SpringBootApplication {

	
	@AliasFor(annotation = EnableAutoConfiguration.class)
	Class[] exclude() default {};

	
	@AliasFor(annotation = EnableAutoConfiguration.class)
	String[] excludeName() default {};

	
	@AliasFor(annotation = ComponentScan.class, attribute = "basePackages")
	String[] scanbasePackages() default {};

	
	@AliasFor(annotation = ComponentScan.class, attribute = "basePackageClasses")
	Class[] scanbasePackageClasses() default {};

	
	@AliasFor(annotation = Configuration.class)
	boolean proxyBeanMethods() default true;

}

Inherited注解：表示子类能继承当前注解的属性

SpringBootConfiguration注解：父注解是Configuration，没明白和Configuration的区别

EnableAutoConfiguration注解：自动装配的实现

ComponentScan注解：扫包，如果不配置，默认扫描当前包

ConfigurationPropertiesScan：配置文件里的属性自动填充到bean

主要看EnableAutoConfiguration注解


package org.springframework.boot.autoconfigure;

import java.lang.annotation.documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory;
import org.springframework.boot.web.servlet.server.ServletWebServerFactory;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.import;
import org.springframework.core.io.support.SpringFactoriesLoader;


@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@documented
@Inherited
@AutoConfigurationPackage //配置扫描包的bean，可以通过这个bean获取到扫描的包路径
@import(AutoConfigurationimportSelector.class) //引入自动装配的配置
public @interface EnableAutoConfiguration {

	String ENABLED_OVERRIDE_PROPERTY = "spring.boot.enableautoconfiguration";

	
	Class[] exclude() default {};

	
	String[] excludeName() default {};

}

AutoConfigurationPackage注解：引入一个AutoConfigurationPackages的bean,bean里有个basePackages的静态内部类保存要扫描的包名称，可以同步AutoConfigurationPackages的get方法获取所有的扫描包的配置

AutoConfigurationimportSelector注解：引入所有自动配置的bean

AutoConfigurationimportSelector源码

https://blog.csdn.net/qq_39482039/article/details/120585957

AutoConfigurationimportSelector主要实现DeferredimportSelector接口，实现了getimportGroup方法返回了AutoConfigurationimportSelector中的AutoConfigurationGroup内部类，会先调用AutoConfigurationGroup内部类的process方法，来将自动配置项设置到当前类的属性中，以便selectimports方法使用

	@Override
		public void process(Annotationmetadata annotationmetadata, DeferredimportSelector deferredimportSelector) {
			Assert.state(deferredimportSelector instanceof AutoConfigurationimportSelector,
					() -> String.format("only %s implementations are supported, got %s",
							AutoConfigurationimportSelector.class.getSimpleName(),
							deferredimportSelector.getClass().getName()));
			//获取自动装配的配置
			AutoConfigurationEntry autoConfigurationEntry = ((AutoConfigurationimportSelector) deferredimportSelector)
					.getAutoConfigurationEntry(getAutoConfigurationmetadata(), annotationmetadata);
			this.autoConfigurationEntries.add(autoConfigurationEntry);
			for (String importClassName : autoConfigurationEntry.getConfigurations()) {
				this.entries.putIfAbsent(importClassName, annotationmetadata);
			}
		}

getAutoConfigurationEntry方法获取自动装配的配置

	
	protected AutoConfigurationEntry getAutoConfigurationEntry(AutoConfigurationmetadata autoConfigurationmetadata,
															   Annotationmetadata annotationmetadata) {
		if (!isEnabled(annotationmetadata)) {
			return EMPTY_ENTRY;
		}
		AnnotationAttributes attributes = getAttributes(annotationmetadata);
		//meta-INF/spring.factories下获取路径是org.springframework.boot.autoconfigure.EnableAutoConfiguration的配置
		List configurations = getCandidateConfigurations(annotationmetadata, attributes);
		//去重，并可以由子类拓展
		configurations = removeDuplicates(configurations);
		//获取排除的自动配置
		Set exclusions = getExclusions(annotationmetadata, attributes);
		//校验配置信息是否可加载，并且不能排除自动配置信息
		checkExcludedClasses(configurations, exclusions);
		//从自动配置移除忽略的
		configurations.removeAll(exclusions);
		//通过meta-INF/spring.factories下AutoConfigurationimportFilter来过滤不需要的bean.
		//也就是通过OnBeanCondition，OnClassCondition，OnWebApplicationCondition来过滤不需要的bean.
		configurations = filter(configurations, autoConfigurationmetadata);
		//执行自动装配加载的监听器
		fireAutoConfigurationimportEvents(configurations, exclusions);
		//封装到AutoConfigurationEntry并返回
		return new AutoConfigurationEntry(configurations, exclusions);
	}

getCandidateConfigurations方法meta-INF/spring.factories下获取路径是org.springframework.boot.autoconfigure.EnableAutoConfiguration的配置

	protected List getCandidateConfigurations(Annotationmetadata metadata, AnnotationAttributes attributes) {
		List 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;
	}

spring.factories文件

# Initializers
org.springframework.context.ApplicationContextInitializer=
org.springframework.boot.autoconfigure.SharedmetadataReaderFactoryContextInitializer,
org.springframework.boot.autoconfigure.logging.ConditionevaluationReportLoggingListener

# Application Listeners
org.springframework.context.ApplicationListener=
org.springframework.boot.autoconfigure.BackgroundPreinitializer

# Auto Configuration import Listeners
org.springframework.boot.autoconfigure.AutoConfigurationimportListener=
org.springframework.boot.autoconfigure.condition.ConditionevaluationReportAutoConfigurationimportListener

# Auto Configuration import Filters
org.springframework.boot.autoconfigure.AutoConfigurationimportFilter=
org.springframework.boot.autoconfigure.condition.OnBeanCondition,
org.springframework.boot.autoconfigure.condition.OnClassCondition,
org.springframework.boot.autoconfigure.condition.onWebApplicationCondition

# 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.batch.BatchAutoConfiguration,
org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,
org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration,
org.springframework.boot.autoconfigure.cloud.CloudServiceConnectorsAutoConfiguration,
org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration,
org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration,
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.CassandraReactiveDataAutoConfiguration,
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveRepositoriesAutoConfiguration,
org.springframework.boot.autoconfigure.data.cassandra.CassandraRepositoriesAutoConfiguration,
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseDataAutoConfiguration,
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveDataAutoConfiguration,
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveRepositoriesAutoConfiguration,
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.elasticsearch.ReactiveElasticsearchRepositoriesAutoConfiguration,
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveRestClientAutoConfiguration,
org.springframework.boot.autoconfigure.data.jdbc.JdbcRepositoriesAutoConfiguration,
org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration,
org.springframework.boot.autoconfigure.data.ldap.LdapRepositoriesAutoConfiguration,
org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration,
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveDataAutoConfiguration,
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveRepositoriesAutoConfiguration,
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.RedisReactiveAutoConfiguration,
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.elasticsearch.rest.RestClientAutoConfiguration,
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration,
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.http.HttpMessageConvertersAutoConfiguration,
org.springframework.boot.autoconfigure.http.codec.CodecsAutoConfiguration,
org.springframework.boot.autoconfigure.influx.InfluxDbAutoConfiguration,
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.groovy.template.GroovyTemplateAutoConfiguration,
org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration,
org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration,
org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration,
org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration,
org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapAutoConfiguration,
org.springframework.boot.autoconfigure.ldap.LdapAutoConfiguration,
org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration,
org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration,
org.springframework.boot.autoconfigure.mail.MailSenderValidatorAutoConfiguration,
org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration,
org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration,
org.springframework.boot.autoconfigure.mongo.MongoReactiveAutoConfiguration,
org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration,
org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration,
org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration,
org.springframework.boot.autoconfigure.rsocket.RSocketMessagingAutoConfiguration,
org.springframework.boot.autoconfigure.rsocket.RSocketRequesterAutoConfiguration,
org.springframework.boot.autoconfigure.rsocket.RSocketServerAutoConfiguration,
org.springframework.boot.autoconfigure.rsocket.RSocketStrategiesAutoConfiguration,
org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration,
org.springframework.boot.autoconfigure.security.servlet.UserDetailsServiceAutoConfiguration,
org.springframework.boot.autoconfigure.security.servlet.SecurityFilterAutoConfiguration,
org.springframework.boot.autoconfigure.security.reactive.ReactiveSecurityAutoConfiguration,
org.springframework.boot.autoconfigure.security.reactive.ReactiveUserDetailsServiceAutoConfiguration,
org.springframework.boot.autoconfigure.security.rsocket.RSocketSecurityAutoConfiguration,
org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyAutoConfiguration,
org.springframework.boot.autoconfigure.sendgrid.SendGridAutoConfiguration,
org.springframework.boot.autoconfigure.session.SessionAutoConfiguration,
org.springframework.boot.autoconfigure.security.oauth2.client.servlet.OAuth2ClientAutoConfiguration,
org.springframework.boot.autoconfigure.security.oauth2.client.reactive.ReactiveOAuth2ClientAutoConfiguration,
org.springframework.boot.autoconfigure.security.oauth2.resource.servlet.OAuth2ResourceServerAutoConfiguration,
org.springframework.boot.autoconfigure.security.oauth2.resource.reactive.ReactiveOAuth2ResourceServerAutoConfiguration,
org.springframework.boot.autoconfigure.solr.SolrAutoConfiguration,
org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration,
org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration,
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration,
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration,
org.springframework.boot.autoconfigure.transaction.jta.JtaAutoConfiguration,
org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration,
org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration,
org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration,
org.springframework.boot.autoconfigure.web.reactive.HttpHandlerAutoConfiguration,
org.springframework.boot.autoconfigure.web.reactive.ReactiveWebServerFactoryAutoConfiguration,
org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration,
org.springframework.boot.autoconfigure.web.reactive.error.ErrorWebFluxAutoConfiguration,
org.springframework.boot.autoconfigure.web.reactive.function.client.ClientHttpConnectorAutoConfiguration,
org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration,
org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration,
org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration,
org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration,
org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration,
org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration,
org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration,
org.springframework.boot.autoconfigure.websocket.reactive.WebSocketReactiveAutoConfiguration,
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketServletAutoConfiguration,
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketMessagingAutoConfiguration,
org.springframework.boot.autoconfigure.webservices.WebServicesAutoConfiguration,
org.springframework.boot.autoconfigure.webservices.client.WebServiceTemplateAutoConfiguration

# Failure analyzers
org.springframework.boot.diagnostics.FailureAnalyzer=
org.springframework.boot.autoconfigure.diagnostics.analyzer.NoSuchBeanDefinitionFailureAnalyzer,
org.springframework.boot.autoconfigure.flyway.FlywayMigrationscriptMissingFailureAnalyzer,
org.springframework.boot.autoconfigure.jdbc.DataSourceBeanCreationFailureAnalyzer,
org.springframework.boot.autoconfigure.jdbc.HikariDriverConfigurationFailureAnalyzer,
org.springframework.boot.autoconfigure.session.NonUniqueSessionRepositoryFailureAnalyzer

# Template availability providers
org.springframework.boot.autoconfigure.template.TemplateAvailabilityProvider=
org.springframework.boot.autoconfigure.freemarker.FreeMarkerTemplateAvailabilityProvider,
org.springframework.boot.autoconfigure.mustache.MustacheTemplateAvailabilityProvider,
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAvailabilityProvider,
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafTemplateAvailabilityProvider,
org.springframework.boot.autoconfigure.web.servlet.JspTemplateAvailabilityProvider

removeDuplicates转为hashset去重

protected final  List removeDuplicates(List list) {
		return new ArrayList<>(new linkedHashSet<>(list));
	}

getExclusions获取注解要排除的自动配置

	protected Set getExclusions(Annotationmetadata metadata, AnnotationAttributes attributes) {
		Set excluded = new linkedHashSet<>();
		excluded.addAll(asList(attributes, "exclude"));
		excluded.addAll(Arrays.asList(attributes.getStringArray("excludeName")));
		excluded.addAll(getExcludeAutoConfigurationsProperty());
		return excluded;
	}

checkExcludedClasses方法自动配置项必须可加载，并且排除的自动配置必须包含在当前的配置项中

private void checkExcludedClasses(List configurations, Set exclusions) {
		List invalidExcludes = new ArrayList<>(exclusions.size());
		for (String exclusion : exclusions) {
			//校验是否可以加载，并且要加载的属性中不包含排除的
			if (ClassUtils.isPresent(exclusion, getClass().getClassLoader()) && !configurations.contains(exclusion)) {
				invalidExcludes.add(exclusion);
			}
		}
		//如果不能加载或者自动配置里不包含排除的配置项，抛异常提示报错
		if (!invalidExcludes.isEmpty()) {
			handleInvalidExcludes(invalidExcludes);
		}
	}

filter方法通过法meta-INF/spring.factories下配置的AutoConfigurationimportFilter来过滤不需要的bean

private List filter(List configurations, AutoConfigurationmetadata autoConfigurationmetadata) {
		long startTime = System.nanoTime();
		String[] candidates = StringUtils.toStringArray(configurations);
		boolean[] skip = new boolean[candidates.length];
		boolean skipped = false;
		for (AutoConfigurationimportFilter filter : getAutoConfigurationimportFilters()) {
			invokeAwareMethods(filter);
			boolean[] match = filter.match(candidates, autoConfigurationmetadata);
			for (int i = 0; i < match.length; i++) {
				if (!match[i]) {
					skip[i] = true;
					candidates[i] = null;
					skipped = true;
				}
			}
		}
		if (!skipped) {
			return configurations;
		}
		List result = new ArrayList<>(candidates.length);
		for (int i = 0; i < candidates.length; i++) {
			if (!skip[i]) {
				result.add(candidates[i]);
			}
		}
		if (logger.isTraceEnabled()) {
			int numberFiltered = configurations.size() - result.size();
			logger.trace("Filtered " + numberFiltered + " auto configuration class in "
					+ TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startTime) + " ms");
		}
		return new ArrayList<>(result);
	}

protected List getAutoConfigurationimportFilters() {
		return SpringFactoriesLoader.loadFactories(AutoConfigurationimportFilter.class, this.beanClassLoader);
	}

fireAutoConfigurationimportEvents方法执行meta-INF/spring.factories下配置的 AutoConfigurationimportListener类型的监听器

private void fireAutoConfigurationimportEvents(List configurations, Set exclusions) {
		//获取到自动配置的监听器
		List listeners = getAutoConfigurationimportListeners();
		if (!listeners.isEmpty()) {
			AutoConfigurationimportEvent event = new AutoConfigurationimportEvent(this, configurations, exclusions);
			for (AutoConfigurationimportListener listener : listeners) {
				//设置Aware
				invokeAwareMethods(listener);
				//执行监听器
				listener.onAutoConfigurationimportEvent(event);
			}
		}
	}

protected List getAutoConfigurationimportListeners() {
		return SpringFactoriesLoader.loadFactories(AutoConfigurationimportListener.class, this.beanClassLoader);
	}

AutoConfigurationGroup中的selectimports方法会将返回的类名数组注解为bean

	@Override
		public Iterable selectimports() {
			if (this.autoConfigurationEntries.isEmpty()) {
				return Collections.emptyList();
			}
			//获取要排除的
			Set allExclusions = this.autoConfigurationEntries.stream()
					.map(AutoConfigurationEntry::getExclusions).flatMap(Collection::stream).collect(Collectors.toSet());
			//获取到自动当前自动装配的属性
			Set processedConfigurations = this.autoConfigurationEntries.stream()
					.map(AutoConfigurationEntry::getConfigurations).flatMap(Collection::stream)
					.collect(Collectors.toCollection(linkedHashSet::new));
			processedConfigurations.removeAll(allExclusions);
			//排序
			return sortAutoConfigurations(processedConfigurations, getAutoConfigurationmetadata()).stream()
					.map((importClassName) -> new Entry(this.entries.get(importClassName), importClassName))
					.collect(Collectors.toList());
		}

springboot源码分析-自动装配

Java相关栏目本月热门文章