Springboot源码分析

2年前 (2022) 程序员胖胖胖虎阿

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文章目录

Springboot源码分析
- 01、SpringBoot三大特性
- 02、传统的spring项目
- 03、springboot的项目：
- 04、如何去学习分析源码
- 05、springboot的零配置是怎么解决的
- 06、Springboot的零配置他们在解决一个什么问题
- 07、怎么认识项目中的bean
- 08、@Import机制，拯救第三方bean加载的IOC容器
- 09、四种机制的分析，如何把bean加载到IOC容器中
- - 9.1、初始化阶段
  - 9.2、运行阶段
  - 9.3、如何和spring IOC 发生关系
  - 9.4、spring生命周期的阶段

Springboot源码分析

01、SpringBoot三大特性

帮助开发者快速整合第三方框架（原理Maven依赖封装）
嵌入服务器（原理java语言创建服务器）
完全注解形式替代XML（原理包装Spring体系注解）

02、传统的spring项目

基于XMl形式
依赖的第三方的模块，都在pom.xml逐个依赖，还需要在xml文件中去配置

配置的目的就是让spring去加载和管理这些bean
需要依赖外部的tomcat容器去部署项目才可以进行项目发布与部署
日志管理，也需要额外的配置
配置组件或者应用非常的玛法和繁复

03、springboot的项目：

零配置，用注解的方式取代传统意义上的xml文件
starter机制
内置了tomcat容器和日志管理。开发起来只需要启动main函数即可。就可以让项目运行起来了
springboot管理的bean是如何注册spring IOC容器

04、如何去学习分析源码

心中一定有方向和目标

springboot项目的整体架构

Springboot源码分析

核心启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringbootstudysourceApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootstudysourceApplication.class, args);
    }
}

05、springboot的零配置是怎么解决的

答案是用：注解

传统的ssm的方式的：

xml – applicationContext.xml

<bean id="xxx" class="xxx">
<bean id="xxx" class="xxx">
<bean id="xxx" class="xxx">

扫包 + 注解

<conpoment-scan basePackeges="com.kuangstudy.service">
<conpoment-scan basePackeges="com.kuangstudy.mapper">
<conpoment-scan basePackeges="com.kuangstudy.controller">

注解：@Service @Controller @RestController @Respostity @Component等

springboot改进

扫包 + 注解
```
@ComponentScan 
```
@Configuration + @Bean配置类 + @Bean初始化

@Import 机制

@Import(配置列 & selector 即可实现类，你也可以写普通bean)
@Import(RedisConfiguration.class)
@Import(UserService.class)
@Import(AxxxSelector.class)

@ImportResource

@ImportResource("classpath:applicationContext.xml")

06、Springboot的零配置他们在解决一个什么问题

抛弃传统的xml方式
也可以集成和整合传统的xml方式，通过@ImportResource。但是不建议混合使用

不管是传统的xml方式还是springboot提供的这四种机制，他们在解决什么问题？

他们都在解决同一个问题

Springboot源码分析

通过不同的方式，把项目中的和第三方依赖全部通过这些机制，放入到spring的IOC容器中。springboot它的核心还是spring。它只不过是对spring这个框架进行了升级和改进。

07、怎么认识项目中的bean

项目中的bean

Springboot源码分析

第三方的依赖 bean

Springboot源码分析

解决方案：

扫包 + 注解（必须这些第三方的报名必须要和当前项目A包名要一致，否则加载不进去）
```
@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan(basePackages = {
      "org.mybatis", "com.alibaba.druid"
})
```
上面的做法，肯定是不可取的。因为这种方式去加载第三方的bean，到项目中ioc去的，肯定非常麻烦，维护起来就是灾难。

08、@Import机制，拯救第三方bean加载的IOC容器

这个就是所谓的：start机制

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.4</version>
</dependency>

官方提供的：spring-boot-starter-xxxx

第三方提供的：xxx-spring-boot-starter

两者的区别：官方不需要加版本号，因为通过parent指定的版本统一升级和管理

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.4.10</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

第三方的遵循springboot的starter机制开发出来的一种形式。它的导入就必须加version

09、四种机制的分析，如何把bean加载到IOC容器中

在启动springboot项目的时候

@SpringBootApplication
public class SpringbootstudysourceApplication {

   public static void main(String[] args) {
      SpringApplication.run(SpringbootstudysourceApplication.class, args);
   }

}

核心方法：

SpringApplication.run(SpringbootstudysourceApplication.class, args);

1. 调用方法如下

public static ConfigurableApplicationContext run(Class<?> primarySource, String... args) {
    return run(new Class[]{primarySource}, args);
}

2. 调用方法如下

public static ConfigurableApplicationContext run(Class<?>[] primarySources, String[] args) {
    return (new SpringApplication(primarySources)).run(args);
}

3. 重点

佐证一个观点：springboot是如何把bean放如到ioc容器中的

return (new SpringApplication(primarySources)).run(args);

#  拆解
// 初始化
SpringApplication application = new SpringApplication(primarySources);
// 运行阶段
application.run(args);

9.1、初始化阶段

new SpringApplication(primarySources)

初始化阶段：把项目中所有符合springboot机制的bean全部收集起来。map

1、调用构造函数方法

public SpringApplication(Class<?>... primarySources) {
    this((ResourceLoader)null, primarySources);
}

2、调用具体的初始化方法过程（核心）

public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) {
    // 1. 初始化数组，集合，开关标记
    this.sources = new LinkedHashSet();
    this.bannerMode = Mode.CONSOLE;
    this.logStartupInfo = true;
    this.addCommandLineProperties = true;
    this.addConversionService = true;
    this.headless = true;
    this.registerShutdownHook = true;
    this.additionalProfiles = Collections.emptySet();
    this.isCustomEnvironment = false;
    this.lazyInitialization = false;
    this.applicationContextFactory = ApplicationContextFactory.DEFAULT;
    this.applicationStartup = ApplicationStartup.DEFAULT;
    this.resourceLoader = resourceLoader;
    Assert.notNull(primarySources, "PrimarySources must not be null");
    this.primarySources = new LinkedHashSet(Arrays.asList(primarySources));
    this.webApplicationType = WebApplicationType.deduceFromClasspath();
    
    // 核心代码1
    this.bootstrapRegistryInitializers = this.getBootstrapRegistryInitializersFromSpringFactories();
    // 核心代码2
    this.setInitializers(this.getSpringFactoriesInstances(ApplicationContextInitializer.class));
    // 核心代码3
    this.setListeners(this.getSpringFactoriesInstances(ApplicationListener.class));
    
    this.mainApplicationClass = this.deduceMainApplicationClass();
}

核心代码1 和核心代码2 和核心代码3 都在调用一个相同的方法：

核心代码1

Springboot源码分析

可以看出，this.getBootstrapRegistryInitializersFromSpringFactories() 最终调用了

this.getSpringFactoriesInstances(BootstrapRegistryInitializer.class)

核心代码2

this.getSpringFactoriesInstances(ApplicationContextInitializer.class)

核心代码3

this.getSpringFactoriesInstances(ApplicationListener.class)

三个都传递了一个类：

1：为什么要传递类？

触发类加载器

2：传递类的作用是干啥？

触发类加载器，通过双亲委派模型，把项目中所有的类，包括jdk、jdkext、target/classes、spring.jar、mybatis.jar 全部把他们中编译好的字节文件class找到，放入map中。

3：怎么找到项目所有需要的bean？

BootstrapRegistryInitializer

其实它这个类不是具体干活的类，它提前把项目中的类全部找到放入缓存map中，然后给ApplicationContextInitializer、ApplicationListener提供一个缓存机制，后面两者的获取对应bean就不会重复去触发类加载器，频繁的扫描过滤。

3、调用具体的 getSpringFactoriesInstances（核心）

Springboot源码分析

下面就是类加载器：AppClassLoader – ExtClassLoader – BootstrapClassLoader(双亲委派模型)

ClassLoader classLoader = this.getClassLoader();

双亲委派模型：一句话，找到项目中所有的class文件，不论jdk、ext、项目写的class、spring.jar统统全部找到。

问：你项目中引入jdk是怎么加载进去的，你项目引入的spring.jar里面的类你为什么就可以使用。你项目String、List为什么就可以使用了呢？

答案：就是因为在启动的时候， 项目会调用类加载器通过双亲委派模型把项目中所有的class全部找到。然后放入到jvm中去，只不过springboot把这些加载到class进行过滤匹配把符合条件的bean放入到IOC容器中的过程。哪些是符合条件的bean呢？

- 扫包 + 注解（@Service, @Controller）
- 是不是符合import机制
- 是不是符合@Configuration + @Bean

Springboot源码分析

4、开始对类加载器加载的类进行过滤

Set<String> names = new LinkedHashSet(SpringFactoriesLoader.loadFactoryNames(type, classLoader));

type：interface org.springframework.boot.Bootstrapper 开始进行匹配过滤。作用其实就是一个加载缓存的目的，作用就是：它会把类加载器中所有的jar文件包含 META-INF/spring.factories 文件中的内容全部找到。然后这个 META-INF/spring.factories 中的bean全部放入到Map中如下：

5、把jar包中包含META-INF/spring.factories 的找到

private static Map<String, List<String>> loadSpringFactories(ClassLoader classLoader) {
    Map<String, List<String>> result = (Map)cache.get(classLoader);
    if (result != null) {
        return result;
    } else {
        HashMap result = new HashMap();

        try {
            // 通过类加载器，把jar中包含META-INF/spring.factories的，找到
            // 这里面的原理是双亲委派
            Enumeration urls = classLoader.getResources("META-INF/spring.factories");

            while(urls.hasMoreElements()) {
                URL url = (URL)urls.nextElement();
                UrlResource resource = new UrlResource(url);
                Properties properties = PropertiesLoaderUtils.loadProperties(resource);
                Iterator var6 = properties.entrySet().iterator();

                while(var6.hasNext()) {
                    Entry<?, ?> entry = (Entry)var6.next();
                    String factoryTypeName = ((String)entry.getKey()).trim();
                    String[] factoryImplementationNames = StringUtils.commaDelimitedListToStringArray((String)entry.getValue());
                    String[] var10 = factoryImplementationNames;
                    int var11 = factoryImplementationNames.length;

                    for(int var12 = 0; var12 < var11; ++var12) {
                        String factoryImplementationName = var10[var12];
                        ((List)result.computeIfAbsent(factoryTypeName, (key) -> {
                            return new ArrayList();
                        })).add(factoryImplementationName.trim());
                    }
                }
            }

            result.replaceAll((factoryType, implementations) -> {
                return (List)implementations.stream().distinct().collect(Collectors.collectingAndThen(Collectors.toList(), Collections::unmodifiableList));
            });
            cache.put(classLoader, result);
            return result;
        } catch (IOException var14) {
            throw new IllegalArgumentException("Unable to load factories from location [META-INF/spring.factories]", var14);
        }
    }
}

springboot是如何把需要的bean加载出来的呢？

我们知道类加载，把项目中所有的class统统都加载到jvm中。这么多的class，springboot是如何把需要管理和初始化放如IOC容器的class找出来的呢？springboot借鉴了java9的新特性：spi机制。这种机制其实就是把需要被加载类放入一个配置中，而springboot命名规则就是：META-INF/spring.factories。

而这个文件中就定义springboot需要加载的所有的bean，都放在这个文件中
现在要做的事情，找到这个文件
解析这个文件
解析以后的bean，放入到map中（仅此而已，千万记住这个时候还没有和spring IOC产生关系）

找到第一个需要解析的jar包：

jar:file:/D:/ProgramFiles/apache-maven-3.6.3/.m2/org/springframework/boot/spring-boot/2.4.10/spring-boot-2.4.10.jar!/META-INF/spring.factories

Springboot源码分析

# Logging Systems
org.springframework.boot.logging.LoggingSystemFactory=\
org.springframework.boot.logging.logback.LogbackLoggingSystem.Factory,\
org.springframework.boot.logging.log4j2.Log4J2LoggingSystem.Factory,\
org.springframework.boot.logging.java.JavaLoggingSystem.Factory

# PropertySource Loaders
org.springframework.boot.env.PropertySourceLoader=\
org.springframework.boot.env.PropertiesPropertySourceLoader,\
org.springframework.boot.env.YamlPropertySourceLoader

# ConfigData Location Resolvers
org.springframework.boot.context.config.ConfigDataLocationResolver=\
org.springframework.boot.context.config.ConfigTreeConfigDataLocationResolver,\
org.springframework.boot.context.config.StandardConfigDataLocationResolver

# ConfigData Loaders
org.springframework.boot.context.config.ConfigDataLoader=\
org.springframework.boot.context.config.ConfigTreeConfigDataLoader,\
org.springframework.boot.context.config.StandardConfigDataLoader

# Run Listeners
org.springframework.boot.SpringApplicationRunListener=\
org.springframework.boot.context.event.EventPublishingRunListener

# Error Reporters
org.springframework.boot.SpringBootExceptionReporter=\
org.springframework.boot.diagnostics.FailureAnalyzers

# Application Context Initializers
org.springframework.context.ApplicationContextInitializer=\
org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer,\
org.springframework.boot.context.ContextIdApplicationContextInitializer,\
org.springframework.boot.context.config.DelegatingApplicationContextInitializer,\
org.springframework.boot.rsocket.context.RSocketPortInfoApplicationContextInitializer,\
org.springframework.boot.web.context.ServerPortInfoApplicationContextInitializer

# Application Listeners
org.springframework.context.ApplicationListener=\
org.springframework.boot.ClearCachesApplicationListener,\
org.springframework.boot.builder.ParentContextCloserApplicationListener,\
org.springframework.boot.context.FileEncodingApplicationListener,\
org.springframework.boot.context.config.AnsiOutputApplicationListener,\
org.springframework.boot.context.config.DelegatingApplicationListener,\
org.springframework.boot.context.logging.LoggingApplicationListener,\
org.springframework.boot.env.EnvironmentPostProcessorApplicationListener,\
org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener

# Environment Post Processors
org.springframework.boot.env.EnvironmentPostProcessor=\
org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor,\
org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor,\
org.springframework.boot.env.RandomValuePropertySourceEnvironmentPostProcessor,\
org.springframework.boot.env.SpringApplicationJsonEnvironmentPostProcessor,\
org.springframework.boot.env.SystemEnvironmentPropertySourceEnvironmentPostProcessor,\
org.springframework.boot.reactor.DebugAgentEnvironmentPostProcessor

# Failure Analyzers
org.springframework.boot.diagnostics.FailureAnalyzer=\
org.springframework.boot.context.config.ConfigDataNotFoundFailureAnalyzer,\
org.springframework.boot.context.properties.IncompatibleConfigurationFailureAnalyzer,\
org.springframework.boot.context.properties.NotConstructorBoundInjectionFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.BeanCurrentlyInCreationFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.BeanDefinitionOverrideFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.BeanNotOfRequiredTypeFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.BindFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.BindValidationFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.UnboundConfigurationPropertyFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.ConnectorStartFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.NoSuchMethodFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.NoUniqueBeanDefinitionFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.PortInUseFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.ValidationExceptionFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.InvalidConfigurationPropertyNameFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.InvalidConfigurationPropertyValueFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.PatternParseFailureAnalyzer,\
org.springframework.boot.liquibase.LiquibaseChangelogMissingFailureAnalyzer

# Failure Analysis Reporters
org.springframework.boot.diagnostics.FailureAnalysisReporter=\
org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter

Springboot源码分析

找到第二个jar进行解析

URL [jar:file:/D:/ProgramFiles/apache-maven-3.6.3/.m2/org/springframework/spring-beans/5.3.9/spring-beans-5.3.9.jar!/META-INF/spring.factories]

org.springframework.beans.BeanInfoFactory=org.springframework.beans.ExtendedBeanInfoFactory

找到第三方jar

Springboot源码分析

# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.mybatis.spring.boot.autoconfigure.MybatisLanguageDriverAutoConfiguration,\
org.mybatis.spring.boot.autoconfigure.MybatisAutoConfiguration

第四个需要解析的jar

URL [jar:file:/D:/ProgramFiles/apache-maven-3.6.3/.m2/org/springframework/boot/spring-boot/2.4.10/spring-boot-2.4.10.jar!/META-INF/spring.factories]

# 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.context.ConfigurationPropertiesAutoConfiguration,\
org.springframework.boot.autoconfigure.context.LifecycleAutoConfiguration,\
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.ElasticsearchDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveElasticsearchRestClientAutoConfiguration,\
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.Neo4jReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.solr.SolrRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.r2dbc.R2dbcDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.r2dbc.R2dbcRepositoriesAutoConfiguration,\
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.ElasticsearchRestClientAutoConfiguration,\
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration,\
org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration,\
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration,\
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.jersey.JerseyAutoConfiguration,\
org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration,\
org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration,\
org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration,\
org.springframework.boot.autoconfigure.availability.ApplicationAvailabilityAutoConfiguration,\
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.neo4j.Neo4jAutoConfiguration,\
org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration,\
org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration,\
org.springframework.boot.autoconfigure.r2dbc.R2dbcAutoConfiguration,\
org.springframework.boot.autoconfigure.r2dbc.R2dbcTransactionManagerAutoConfiguration,\
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.data.redis.RedisUrlSyntaxFailureAnalyzer,\
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.r2dbc.ConnectionFactoryBeanCreationFailureAnalyzer,\
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

org.springframework.boot.autoconfigure.EnableAutoConfiguration

就是这个注解对应的所有的配置类。这些配置类，是如何加载到IOC容器中的呢？（运行阶段）

Springboot源码分析

但是这些bean真的全部放进去吗？答案：否

为什么初始化阶段还没有放入IOC容器中？

答：因为初始化阶段仅仅是一个解析和准备的工作，就把需要的bean全部找到，仅此而已。

Application Context Initializers

org.springframework.context.ApplicationContextInitializer=
org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer,
org.springframework.boot.context.ContextIdApplicationContextInitializer,
org.springframework.boot.context.config.DelegatingApplicationContextInitializer,
org.springframework.boot.rsocket.context.RSocketPortInfoApplicationContextInitializer,
org.springframework.boot.web.context.ServerPortInfoApplicationContextInitializer

Springboot源码分析

Run ---- 1 2 3 4 5 6 7 -----selectImports

1: 执行run方法

Springboot源码分析

2：

this.refreshContext(context);

3：

protected void refresh(ConfigurableApplicationContext applicationContext) {
    applicationContext.refresh();
}

4：

protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
    PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, this.getBeanFactoryPostProcessors());
    if (!NativeDetector.inNativeImage() && beanFactory.getTempClassLoader() == null && beanFactory.containsBean("loadTimeWeaver")) {
        beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
        beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
    }

}

5：

invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry, beanFactory.getApplicationStartup());

6：

postProcessor.postProcessBeanDefinitionRegistry(registry);

7：

public void processConfigBeanDefinitions(BeanDefinitionRegistry registry) {
    
     parser.parse(candidates);

public void processGroupImports() {
    Iterator var1 = this.groupings.values().iterator();

    while(var1.hasNext()) {
        ConfigurationClassParser.DeferredImportSelectorGrouping grouping = (ConfigurationClassParser.DeferredImportSelectorGrouping)var1.next();
        Predicate<String> exclusionFilter = grouping.getCandidateFilter();
        grouping.getImports().forEach((entry) -> {
            ConfigurationClass configurationClass = (ConfigurationClass)this.configurationClasses.get(entry.getMetadata());

            try {
                ConfigurationClassParser.this.processImports(configurationClass, ConfigurationClassParser.this.asSourceClass(configurationClass, exclusionFilter), Collections.singleton(ConfigurationClassParser.this.asSourceClass(entry.getImportClassName(), exclusionFilter)), exclusionFilter, false);
            } catch (BeanDefinitionStoreException var5) {
                throw var5;
            } catch (Throwable var6) {
                throw new BeanDefinitionStoreException("Failed to process import candidates for configuration class [" + configurationClass.getMetadata().getClassName() + "]", var6);
            }
        });
    }

}

Springboot源码分析

Application Listeners

org.springframework.context.ApplicationListener=
org.springframework.boot.ClearCachesApplicationListener,
org.springframework.boot.builder.ParentContextCloserApplicationListener,
org.springframework.boot.context.FileEncodingApplicationListener,
org.springframework.boot.context.config.AnsiOutputApplicationListener,
org.springframework.boot.context.config.DelegatingApplicationListener,
org.springframework.boot.context.logging.LoggingApplicationListener,
org.springframework.boot.env.EnvironmentPostProcessorApplicationListener,
org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener

9.2、运行阶段

.run(args)

把初始化阶段所有收集的bean，全部初始化放入到IOC容器中，再去经历spring生命周期，运行结束。

证明：启动类在启动默认情况下，会把当前主类的包名作为包入口

也就是@ComponentScan 的原理。其实它背后有一个类在做事情。如下：

org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer

但是注意：是run()运行阶段做的事情

如何证明：注解的解析和放入IOC是在运行阶段去执行和解析的呢？

初始化的构造函数结束行打个断点 —> run方法开头打个断点 —> 在解析类中打个断点

如果是按照这个执行的话，说明初始化阶段仅仅就解析spring.factories 这个文件和收集对应需要初始化的bean。并且证明注解的解析和bean初始化都是在run方法中执行
初始化的构造函数结束行打个断点 —> 在解析类中打个断点（错误）

9.3、如何和spring IOC 发生关系

run方法执行：this.refreshContext(context);

9.4、spring生命周期的阶段

public void refresh() throws BeansException, IllegalStateException {
    synchronized(this.startupShutdownMonitor) {
        StartupStep contextRefresh = this.applicationStartup.start("spring.context.refresh");
        this.prepareRefresh();
        ConfigurableListableBeanFactory beanFactory = this.obtainFreshBeanFactory();
        this.prepareBeanFactory(beanFactory);

        try {
            this.postProcessBeanFactory(beanFactory);
            StartupStep beanPostProcess = this.applicationStartup.start("spring.context.beans.post-process");
            this.invokeBeanFactoryPostProcessors(beanFactory);
            this.registerBeanPostProcessors(beanFactory);
            beanPostProcess.end();
            this.initMessageSource();
            this.initApplicationEventMulticaster();
            this.onRefresh();
            this.registerListeners();
            this.finishBeanFactoryInitialization(beanFactory);
            this.finishRefresh();
        } catch (BeansException var10) {
            if (this.logger.isWarnEnabled()) {
                this.logger.warn("Exception encountered during context initialization - cancelling refresh attempt: " + var10);
            }

            this.destroyBeans();
            this.cancelRefresh(var10);
            throw var10;
        } finally {
            this.resetCommonCaches();
            contextRefresh.end();
        }

    }
}