【移動應(yīng)用開發(fā)技術(shù)】SpringBoot自動裝配原理的知識點有哪些

【移動應(yīng)用開發(fā)技術(shù)】SpringBoot自動裝配原理的知識點有哪些

這篇文章主要介紹“SpringBoot自動裝配原理的知識點有哪些”，在日常操作中，相信很多人在SpringBoot自動裝配原理的知識點有哪些問題上存在疑惑，在下查閱了各式資料，整理出簡單好用的操作方法，希望對大家解答”SpringBoot自動裝配原理的知識點有哪些”的疑惑有所幫助！接下來，請跟著在下一起來學習吧！SpringBoot自動裝配原理自動裝配原理pom.xmlspring-boot-dependencies：核心依賴在父工程中！我們在寫或者寫入一些springboot依賴的時候，不需要指定版本，就因為有這些版本倉庫啟動器

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter</artifactId>

</dependency>啟動器：說白了就是SpringBoot的啟動場景比如：spring-boot-starter-web，他就會幫我們自動導(dǎo)入web環(huán)境所有的依賴！SpringBoot會將所有的功能場景，都變成一個個的啟動器我們要使用什么功能，就只需要找到對用的啟動器就可以了starter主程序@SpringBootApplication

//

標注這個類是一個Springboot的應(yīng)用

public

class

SpringbootHelloworldApplication

{

public

static

void

main(String[]

args)

{

//

將SpringBoot應(yīng)用啟動

SpringApplication.run(SpringbootHelloworldApplication.class,

args);

}

}注解原理：SpringBoot啟動的時候加載主配置類，開啟了自動配置功能@EnableAutoConfiguration@SpringBootApplication

//

加載主配置類

@EnableAutoConfiguration//

開啟了自動配置功能

@Import({AutoConfigurationImportSelector.class})

AutoConfigurationImportSelector

//

這個新版本的，舊版本是

EnableAutoConfigurationImportSelector

-

利用AutoConfigurationImportSelector給容器中導(dǎo)入一些組件

-

可以查看selectImports()方法的內(nèi)容；

-

List<String>

configurations

=

this.getCandidateConfigurations(annotationMetadata,

attributes);//

獲取候選的配置

protected

List<String>

getCandidateConfigurations(AnnotationMetadata

metadata,

AnnotationAttributes

attributes)

{

List<String>

configurations

=

SpringFactoriesLoader.loadFactoryNames(this.getSpringFactoriesLoaderFactoryClass(),

this.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;

}

SpringFactoriesLoader.loadFactoryNames()

掃描所有jar包類路徑下

META-INF/spring.factories

把掃描到的這些文件的內(nèi)容包裝成List對象

從List中獲取到EnableAutoConfiguration.class類（類名）對應(yīng)的值，然后把他們添加在容器中將類路徑下META-INF/spring.factories里面配置的所有EnableAutoConfiguration的值加入到了容器中#

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.h3.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,\

.ProjectInfoAutoConfiguration,\

egration.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.oauth3.client.servlet.OAuth3ClientAutoConfiguration,\

org.springframework.boot.autoconfigure.security.oauth3.client.reactive.ReactiveOAuth3ClientAutoConfiguration,\

org.springframework.boot.autoconfigure.security.oauth3.resource.servlet.OAuth3ResourceServerAutoConfiguration,\

org.springframework.boot.autoconfigure.security.oauth3.resource.reactive.ReactiveOAuth3ResourceServerAutoConfiguration,\

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每一個這樣的xxxAutoConfiguration類都是容器中的一個組件，都加入到容器中；用他們來做自動配置；每一個自動配置類進行自動配置功能；以HttpEncodingAutoConfiguration（Http編碼自動配置）為例解釋自動配置原理；@Configuration

//表示這是一個配置類，以前編寫的配置文件一樣，也可以給容器中添加組件

@EnableConfigurationProperties(ServerProperties.class)

//啟動指定類的ConfigurationProperties功能；將配置文件中對應(yīng)的值和

ServerProperties

綁定起來；并把

ServerProperties

加入到ioc容器中

@ConditionalOnWebApplication

//Spring底層@Conditional注解（Spring注解版），根據(jù)不同的條件，如果滿足指定的條件，整個配置類里面的配置就會生效；

判斷當前應(yīng)用是否是web應(yīng)用，如果是，當前配置類生效

@ConditionalOnClass(CharacterEncodingFilter.class)

//判斷當前項目有沒有這個類CharacterEncodingFilter；SpringMVC中進行亂碼解決的過濾器；

@ConditionalOnProperty(prefix

=

"spring.http.encoding",

value

=

"enabled",

matchIfMissing

=

true)

//判斷配置文件中是否存在某個配置

spring.http.encoding.enabled；如果不存在，判斷也是成立的

//即使我們配置文件中不配置pring.http.encoding.enabled=true，也是默認生效的；

public

class

HttpEncodingAutoConfiguration

{

//他已經(jīng)和SpringBoot的配置文件映射了

private

final

HttpEncodingProperties

properties;

//只有一個有參構(gòu)造器的情況下，參數(shù)的值就會從容器中拿

public

HttpEncodingAutoConfiguration(HttpEncodingProperties

properties)

{

perties

=

properties;

}

@Bean

//給容器中添加一個組件，這個組件的某些值需要從properties中獲取

@ConditionalOnMissingBean(CharacterEncodingFilter.class)

//判斷容器沒有這個組件？

public

CharacterEncodingFilter

characterEncodingFilter()

{

CharacterEncodingFilter

filter

=

new

OrderedCharacterEncodingFilter();

filter.setEncoding(perties.getCharset().name());

filter.setForceRequestEncoding(perties.shouldForce(Type.REQUEST));

filter.setForceResponseEncoding(perties.shouldForce(Type.RESPONSE));

return

filter;

}根據(jù)當前不同的條件判斷，決定這個配置類是否生效？一但這個配置類生效；這個配置類就會給容器中添加各種組件；這些組件的屬性是從對應(yīng)的properties類中獲取的，這些類里面的每一個屬性又是和配置文件綁定的；5）、所有在配置文件中能配置的屬性都是在xxxxProperties類中封裝者‘；配置文件能配置什么就可以參照某個功能對應(yīng)的這個屬性類@ConfigurationProperties(prefix

=

"spring.http.encoding")

//從配置文件中獲取指定的值和bean的屬性進行綁定

public

class

HttpEncodingProperties

{

public

static

final

Charset

DEFAULT_CHARSET

=

Charset.forName("UTF-8");精髓：1）、SpringBoot啟動會加載大量的自動配置類

2）、我們看我們需要的功能有沒有SpringBoot默認寫好的自動配置類；

3）、我們再來看這個自動配置類中到底配置了哪些組件；（只要我們要用的組件有，我們就不需要再來配置了）

4）、給容器中自動配置類添加組件的時候，會從properties類中獲取某些屬性。我們就可以在配置文件中指定這些屬性的值；xxxxAutoConfigurartion：自動配置類；給容器中添加組件xxxxProperties:封裝配置文件中相關(guān)屬性；細節(jié)@Conditional派生注解（Spring注解版原生的@Conditional作用）作用：必須是@Conditional指定的條件成立，才給容器中添加組件，配置配里面的所有內(nèi)容才生效；@Conditional擴展注解作