网站建设一条龙全包seo,专业婚纱摄影网站制作,wordpress自动同步,长沙免费建站模板本篇将详细讨论Spring Boot 的启动/加载、处理请求的具体流程。我们先从一个简单的Spring Boot项目日志开始分析#xff08;这里假设读者已经仔细阅读完了前面的文章#xff0c;且对Spring源码有一定深度的了解#xff0c;否则会看得一脸懵逼#xff09;。
本文为2024重置…本篇将详细讨论Spring Boot 的启动/加载、处理请求的具体流程。我们先从一个简单的Spring Boot项目日志开始分析这里假设读者已经仔细阅读完了前面的文章且对Spring源码有一定深度的了解否则会看得一脸懵逼。
本文为2024重置版基于JDK8、Spring Boot 2.2.6.RELEASE最初版本基于Spring MVC XML配置现已废弃去除。
一、相关代码
1、pom.xml
?xml version1.0 encodingUTF-8?
project xmlnshttp://maven.apache.org/POM/4.0.0 xmlns:xsihttp://www.w3.org/2001/XMLSchema-instance xsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsdparentgroupIdsite.xiaokui/groupIdartifactIdk-2019/artifactIdversion1.0.0/version/parentmodelVersion4.0.0/modelVersionartifactIdk-mini/artifactIddependenciesdependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-web/artifactId/dependency/dependencies
/project2、相关类
SpringBootApplication
public class MiniAppRunner {public static void main(String[] args) {SpringApplication.run(MiniAppRunner.class, args);}
}Slf4j
RequiredArgsConstructor
RestController
public class TestController {PostMapping(/test)ResponseBodypublic Object test0(RequestBody MapString, Object map) {log.info(前端传来数据: map);return map;}
}POST http://127.0.0.1:7077/test?aa1bb2
Content-Type: application/json{data: {login_type: 08,login_str: abcd}
}3、相关配置
debug: trueserver:port: 7077logging:level.root: tracelevel.org.apache.tomcat: infolevel.sun.rmi: info以上为相关测试代码读者也可搭建环境自行测试省略具体输出日志。
二、SpringApplication
1、构造方法
// main方法入口来自类 SpringApplication
public static ConfigurableApplicationContext run(Class? primarySource, String... args) {return run(new Class?[] { primarySource }, args);
}public static ConfigurableApplicationContext run(Class?[] primarySources, String[] args) {return new SpringApplication(primarySources).run(args);
}public SpringApplication(Class?... primarySources) {this(null, primarySources);
}public SpringApplication(ResourceLoader resourceLoader, Class?... primarySources) {this.resourceLoader resourceLoader;Assert.notNull(primarySources, PrimarySources must not be null);this.primarySources new LinkedHashSet(Arrays.asList(primarySources));// 判断当前运行环境可选 none、servlet、reactivethis.webApplicationType WebApplicationType.deduceFromClasspath();// 读取 META-INF/spring.factories加载相关启动类// 加载初始化相关类共有7个 5 2数字刚好与下文的两份 spring.factories对上// 注意这里只是设置还尚未开始调用setInitializers((Collection) getSpringFactoriesInstances(ApplicationContextInitializer.class));// 加载监听器监听相关事件共有11个 10 1setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));// 寻找main方法所在的类作为主类this.mainApplicationClass deduceMainApplicationClass();
}2、spring.factories
来自jar包 org.springframework.boot:spring-boot:2.2.6.REALEASE。
# PropertySource Loaders
org.springframework.boot.env.PropertySourceLoader\
org.springframework.boot.env.PropertiesPropertySourceLoader,\
org.springframework.boot.env.YamlPropertySourceLoader# 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 Initializers5个
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 Listeners10个
org.springframework.context.ApplicationListener\
org.springframework.boot.ClearCachesApplicationListener,\
org.springframework.boot.builder.ParentContextCloserApplicationListener,\
org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor,\
org.springframework.boot.context.FileEncodingApplicationListener,\
org.springframework.boot.context.config.AnsiOutputApplicationListener,\
org.springframework.boot.context.config.ConfigFileApplicationListener,\
org.springframework.boot.context.config.DelegatingApplicationListener,\
org.springframework.boot.context.logging.ClasspathLoggingApplicationListener,\
org.springframework.boot.context.logging.LoggingApplicationListener,\
org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener# Environment Post Processors
org.springframework.boot.env.EnvironmentPostProcessor\
org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor,\
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.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# FailureAnalysisReporters
org.springframework.boot.diagnostics.FailureAnalysisReporter\
org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter来自来自jar包 org.springframework.boot:spring-boot-autoconfigure:2.2.6.REALEASE。
# Initializers2个
org.springframework.context.ApplicationContextInitializer\
org.springframework.boot.autoconfigure.SharedMetadataReaderFactoryContextInitializer,\
org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener# Application Listeners1个
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.JspTemplateAvailabilityProvider3、事件周期图
下图展现SpringApplication的事件全生命周期读者可以按照此图对照源码进行阅读。其中相关核心类有断点神类
SpringApplicationSimpleApplicationEventMulticaster 4、主干
// 主干逻辑
public ConfigurableApplicationContext run(String... args) {// 统计耗时StopWatch stopWatch new StopWatch();stopWatch.start();// WebApplicationContextConfigurableApplicationContext context null;CollectionSpringBootExceptionReporter exceptionReporters new ArrayList();// 设置无图形界面服务器工作模式configureHeadlessProperty();SpringApplicationRunListeners listeners getRunListeners(args);// 触发事件 ApplicationStartingEvent// 分别为 LoggingApplicationListener、BackgroundPreinitializer、DelegatingApplicationListener、LiquibaseServiceLocatorApplicationListener// 这里重点关注下 LoggingApplicationListener、BackgroundPreinitializerlisteners.starting();try {ApplicationArguments applicationArguments new DefaultApplicationArguments(args);// 准备环境包含各种系统属性、环境变量、配置值// 触发事件 ApplicationEnvironmentPreparedEventConfigurableEnvironment environment prepareEnvironment(listeners, applicationArguments);configureIgnoreBeanInfo(environment);Banner printedBanner printBanner(environment);// 创建 AnnotationConfigServletWebServerApplicationContextcontext createApplicationContext();exceptionReporters getSpringFactoriesInstances(SpringBootExceptionReporter.class,new Class[] { ConfigurableApplicationContext.class }, context);// 触发 applyInitializers// 触发事件 ApplicationContextInitializedEvent、ApplicationPreparedEventprepareContext(context, environment, listeners, applicationArguments, printedBanner);// 完成刷新触发事件 ContextRefreshedEvent、ServletWebServerInitializedEventrefreshContext(context);// 空实现留作扩展afterRefresh(context, applicationArguments// 完成统计耗时stopWatch.stop();if (this.logStartupInfo) {// 打印启动耗时// Started MiniAppRunner in 106.05 seconds (JVM running for 189.145)new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), stopWatch);}// 触发事件 ApplicationStartedEventlisteners.started(context);// 调用 ApplicationRunner、CommandLineRunnercallRunners(context, applicationArguments);}catch (Throwable ex) {handleRunFailure(context, ex, exceptionReporters, listeners);throw new IllegalStateException(ex);}try {// 发布事件 ApplicationReadyEvent代表Spring已经完全启动了listeners.running(context);}catch (Throwable ex) {handleRunFailure(context, ex, exceptionReporters, null);throw new IllegalStateException(ex);}return context;
}三、系统属性初始化
1、ApplicationStartingEvent
1、LoggingApplicationListener
// 来自类 LoggingApplicationListener
Override
public void onApplicationEvent(ApplicationEvent event) {// 系统开始启动事件if (event instanceof ApplicationStartingEvent) {onApplicationStartingEvent((ApplicationStartingEvent) event);}else if (event instanceof ApplicationEnvironmentPreparedEvent) {onApplicationEnvironmentPreparedEvent((ApplicationEnvironmentPreparedEvent) event);}else if (event instanceof ApplicationPreparedEvent) {onApplicationPreparedEvent((ApplicationPreparedEvent) event);}else if (event instanceof ContextClosedEvent ((ContextClosedEvent) event).getApplicationContext().getParent() null) {onContextClosedEvent();}else if (event instanceof ApplicationFailedEvent) {onApplicationFailedEvent();}
}private void onApplicationStartingEvent(ApplicationStartingEvent event) {// 准备 LoggingSystemthis.loggingSystem LoggingSystem.get(event.getSpringApplication().getClassLoader());// 日志系统初始化之前的准备工作this.loggingSystem.beforeInitialize();
}// 来自类 LoggingSystem
Override
public void beforeInitialize() {LoggerContext loggerContext getLoggerContext();if (isAlreadyInitialized(loggerContext)) {return;}// 会触发父类 Slf4JLoggingSystem 的初始化// 此步骤会尽量保证系统只有一个日志框架生效例如jdklog、logback、log4j只会生效一个super.beforeInitialize();loggerContext.getTurboFilterList().add(FILTER);
}2、BackgroundPreinitializer
// 来自类 BackgroundPreinitializer
Override
public void onApplicationEvent(SpringApplicationEvent event) {if (!Boolean.getBoolean(IGNORE_BACKGROUNDPREINITIALIZER_PROPERTY_NAME) event instanceof ApplicationStartingEvent multipleProcessors() preinitializationStarted.compareAndSet(false, true)) {performPreinitialization();}if ((event instanceof ApplicationReadyEvent || event instanceof ApplicationFailedEvent) preinitializationStarted.get()) {try {preinitializationComplete.await();}catch (InterruptedException ex) {Thread.currentThread().interrupt();}}
}// 主要作用是执行类的预热因为组件较多提前异步实例化可提升系统启动速度
// 实例化好的对象最终会保存到一个静态对象中下次直接使用即可
private void performPreinitialization() {try {Thread thread new Thread(new Runnable() {Overridepublic void run() {runSafely(new ConversionServiceInitializer());runSafely(new ValidationInitializer());runSafely(new MessageConverterInitializer());runSafely(new JacksonInitializer());runSafely(new CharsetInitializer());preinitializationComplete.countDown();}public void runSafely(Runnable runnable) {try {runnable.run();}catch (Throwable ex) {// Ignore}}}, background-preinit);thread.start();}catch (Exception ex) {// This will fail on GAE where creating threads is prohibited. We can safely// continue but startup will be slightly slower as the initialization will now// happen on the main thread.preinitializationComplete.countDown();}
}2、prepareEnvironment
private ConfigurableEnvironment prepareEnvironment(SpringApplicationRunListeners listeners,ApplicationArguments applicationArguments) {// Create and configure the environment// 此时具有环境变量和系统属性但还未有配置文件属性ConfigurableEnvironment environment getOrCreateEnvironment();configureEnvironment(environment, applicationArguments.getSourceArgs());ConfigurationPropertySources.attach(environment);// 发布环境就绪事件// 会触发监听类 ConfigFileApplicationListener、AnsiOutputApplicationListener、LoggingApplicationListener// ClasspathLoggingApplicationListener、BackgroundPreinitializer、DelegatingApplicationListener、FileEncodingApplicationListenerlisteners.environmentPrepared(environment);bindToSpringApplication(environment);if (!this.isCustomEnvironment) {environment new EnvironmentConverter(getClassLoader()).convertEnvironmentIfNecessary(environment,deduceEnvironmentClass());}ConfigurationPropertySources.attach(environment);return environment;
}
1、getOrCreateEnvironment
private ConfigurableEnvironment getOrCreateEnvironment() {if (this.environment ! null) {return this.environment;}switch (this.webApplicationType) {// 走此逻辑case SERVLET:return new StandardServletEnvironment();case REACTIVE:return new StandardReactiveWebEnvironment();default:return new StandardEnvironment();}
}public class StandardServletEnvironment extends StandardEnvironment implements ConfigurableWebEnvironment {}// 会首先触发父类的初始化
public AbstractEnvironment() {// 开始读取配置customizePropertySources(this.propertySources);
}// 来自类 StandardServletEnvironment
Override
protected void customizePropertySources(MutablePropertySources propertySources) {propertySources.addLast(new StubPropertySource(SERVLET_CONFIG_PROPERTY_SOURCE_NAME));propertySources.addLast(new StubPropertySource(SERVLET_CONTEXT_PROPERTY_SOURCE_NAME));if (JndiLocatorDelegate.isDefaultJndiEnvironmentAvailable()) {propertySources.addLast(new JndiPropertySource(JNDI_PROPERTY_SOURCE_NAME));}// 回调父类 customizePropertySourcessuper.customizePropertySources(propertySources);
}// 来自类 StandardEnvironment
Override
protected void customizePropertySources(MutablePropertySources propertySources) {// 底层为 (Map) System.getProperties()propertySources.addLast(new PropertiesPropertySource(SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME, getSystemProperties()));// 底层为 (Map) System.getenv()propertySources.addLast(new SystemEnvironmentPropertySource(SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME, getSystemEnvironment()));
}2、ApplicationEnvironmentPreparedEvent
限于篇幅这里不详细展开大概列下
ConfigFileApplicationListener用于加载外部配置文件。AnsiOutputApplicationListener让你的终端可以是控制台、可以是日志文件支持Ansi彩色输出。LoggingApplicationListener初始化日志系统。ClasspathLoggingApplicationListener用于把classpath路径以log.debug()输出。BackgroundPreinitializer无动作。DelegatingApplicationListener执行通过外部化配置context.listener.classes xxx,xxx的监听器们然后把该事件广播给他们。FileEncodingApplicationListener检查文件编码file.encoding。
ConfigFileApplicationListener 部分关键代码如下
// 来自类 ConfigFileApplicationListener
Override
public void onApplicationEvent(ApplicationEvent event) {if (event instanceof ApplicationEnvironmentPreparedEvent) {onApplicationEnvironmentPreparedEvent((ApplicationEnvironmentPreparedEvent) event);}if (event instanceof ApplicationPreparedEvent) {onApplicationPreparedEvent(event);}
}private void onApplicationEnvironmentPreparedEvent(ApplicationEnvironmentPreparedEvent event) {// 分别为 SystemEnvironmentPropertySourceEnvironmentPostProcessor、SpringApplicationJsonEnvironmentPostProcessor// CloudFoundryVcapEnvironmentPostProcessor、DebugAgentEnvironmentPostProcessorListEnvironmentPostProcessor postProcessors loadPostProcessors();// 注意 add this了// 读取外部配置这个最重要的活是自己来干postProcessors.add(this);AnnotationAwareOrderComparator.sort(postProcessors);for (EnvironmentPostProcessor postProcessor : postProcessors) {postProcessor.postProcessEnvironment(event.getEnvironment(), event.getSpringApplication());}
}// 来自类 ConfigFileApplicationListener
Override
public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {addPropertySources(environment, application.getResourceLoader());
}// 鉴于代码较多这里只列举部分关键代码
// 默认配置文件路径 DEFAULT_SEARCH_LOCATIONS classpath:/,classpath:/config/,file:./,file:./config/;
private void load(Profile profile, DocumentFilterFactory filterFactory, DocumentConsumer consumer) {getSearchLocations().forEach((location) - {boolean isFolder location.endsWith(/);SetString names isFolder ? getSearchNames() : NO_SEARCH_NAMES;names.forEach((name) - load(location, name, profile, filterFactory, consumer));});
}LoggingApplicationListener 部分关键代码如下
// 来自类 LoggingApplicationListener
private void onApplicationEnvironmentPreparedEvent(ApplicationEnvironmentPreparedEvent event) {// 上一事件已经完成准备工作if (this.loggingSystem null) {this.loggingSystem LoggingSystem.get(event.getSpringApplication().getClassLoader());}// 直接跳到这里开始初始化initialize(event.getEnvironment(), event.getSpringApplication().getClassLoader());
}protected void initialize(ConfigurableEnvironment environment, ClassLoader classLoader) {// 设置日志属性默认值new LoggingSystemProperties(environment).apply();// 日志文件名 logging.file.name、logging.file// 日志文件路径 logging.file.path、logging.paththis.logFile LogFile.get(environment);if (this.logFile ! null) {this.logFile.applyToSystemProperties();}// 默认logger web sqlthis.loggerGroups new LoggerGroups(DEFAULT_GROUP_LOGGERS);// 设置early日志级别主要是 debug/trace true/falseinitializeEarlyLoggingLevel(environment);// 根据日志配置初始化日志系统包括 日志输出格式、日志存放路径、日志存放策略等initializeSystem(environment, this.loggingSystem, this.logFile);// 设置日志级别含root和各个子包路径initializeFinalLoggingLevels(environment, this.loggingSystem);// 注册销毁钩子registerShutdownHookIfNecessary(environment, this.loggingSystem);
}3、printBanner
打印banner关键类为 SpringApplicationBannerPrinter这里不做详细展开。
// 只列举部分字段
class SpringApplicationBannerPrinter {static final String BANNER_LOCATION_PROPERTY spring.banner.location;static final String BANNER_IMAGE_LOCATION_PROPERTY spring.banner.image.location;static final String DEFAULT_BANNER_LOCATION banner.txt;static final String[] IMAGE_EXTENSION { gif, jpg, png };// 默认打印 spring boot 版本信息private static final Banner DEFAULT_BANNER new SpringBootBanner();private final ResourceLoader resourceLoader;private final Banner fallbackBanner;// 其他略
}四、WebApplication初始化
1、createApplicationContext
// 来自类 SpringApplication
protected ConfigurableApplicationContext createApplicationContext() {Class? contextClass this.applicationContextClass;if (contextClass null) {try {switch (this.webApplicationType) {case SERVLET:// 走此逻辑类为 AnnotationConfigServletWebServerApplicationContextcontextClass Class.forName(DEFAULT_SERVLET_WEB_CONTEXT_CLASS);break;case REACTIVE:// AnnotationConfigReactiveWebServerApplicationContextcontextClass Class.forName(DEFAULT_REACTIVE_WEB_CONTEXT_CLASS);break;default:// AnnotationConfigApplicationContext contextClass Class.forName(DEFAULT_CONTEXT_CLASS);}}catch (ClassNotFoundException ex) {throw new IllegalStateException(Unable create a default ApplicationContext, please specify an ApplicationContextClass, ex);}}return (ConfigurableApplicationContext) BeanUtils.instantiateClass(contextClass);
}2、prepareContext
private void prepareContext(ConfigurableApplicationContext context, ConfigurableEnvironment environment,SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments, Banner printedBanner) {context.setEnvironment(environment);postProcessApplicationContext(context);// 触发初始化逻辑共7个具体参见前文applyInitializers(context);// 发布事件 ApplicationContextInitializedEventlisteners.contextPrepared(context);if (this.logStartupInfo) {logStartupInfo(context.getParent() null);logStartupProfileInfo(context);}// Add boot specific singleton beansConfigurableListableBeanFactory beanFactory context.getBeanFactory();beanFactory.registerSingleton(springApplicationArguments, applicationArguments);if (printedBanner ! null) {beanFactory.registerSingleton(springBootBanner, printedBanner);}if (beanFactory instanceof DefaultListableBeanFactory) {((DefaultListableBeanFactory) beanFactory).setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);}if (this.lazyInitialization) {context.addBeanFactoryPostProcessor(new LazyInitializationBeanFactoryPostProcessor());}// Load the sourcesSetObject sources getAllSources();Assert.notEmpty(sources, Sources must not be empty);load(context, sources.toArray(new Object[0]));// 发布 ApplicationPreparedEventlisteners.contextLoaded(context);
}
1、applyInitializers
// 触发相关类为 DelegatingApplicationContextInitializer、SharedMetadataReaderFactoryContextInitializer、ContextIdApplicationContextInitializer
// ConfigurationWarningsApplicationContextInitializer、RSocketPortInfoApplicationContextInitializer
// ServerPortInfoApplicationContextInitializer、ConditionEvaluationReportLoggingListener
protected void applyInitializers(ConfigurableApplicationContext context) {for (ApplicationContextInitializer initializer : getInitializers()) {Class? requiredType GenericTypeResolver.resolveTypeArgument(initializer.getClass(),ApplicationContextInitializer.class);Assert.isInstanceOf(requiredType, context, Unable to call initializer.);initializer.initialize(context);}
}2、contextPrepared
// 来自类 SpringApplicationRunListeners
// 发布WebApplication就绪事件
void contextPrepared(ConfigurableApplicationContext context) {for (SpringApplicationRunListener listener : this.listeners) {listener.contextPrepared(context);}
}// 来自类 EventPublishingRunListener
Override
public void contextPrepared(ConfigurableApplicationContext context) {this.initialMulticaster.multicastEvent(new ApplicationContextInitializedEvent(this.application, this.args, context));
} 3、contextLoaded
// 来自类 SpringApplicationRunListeners
// 发布WebApplication加载完毕事件
void contextLoaded(ConfigurableApplicationContext context) {for (SpringApplicationRunListener listener : this.listeners) {listener.contextLoaded(context);}
}// 来自类 EventPublishingRunListener
Override
public void contextLoaded(ConfigurableApplicationContext context) {for (ApplicationListener? listener : this.application.getListeners()) {if (listener instanceof ApplicationContextAware) {((ApplicationContextAware) listener).setApplicationContext(context);}context.addApplicationListener(listener);}this.initialMulticaster.multicastEvent(new ApplicationPreparedEvent(this.application, this.args, context));
} 3、refreshContext
// 来自类 SpringApplication
private void refreshContext(ConfigurableApplicationContext context) {refresh(context);if (this.registerShutdownHook) {try {context.registerShutdownHook();}catch (AccessControlException ex) {// Not allowed in some environments.}}
}protected void refresh(ApplicationContext applicationContext) {Assert.isInstanceOf(AbstractApplicationContext.class, applicationContext);// 触发上下文的刷新动作// 这里不做过多展开具体请参见前文((AbstractApplicationContext) applicationContext).refresh();
}public CollectionApplicationListener? getApplicationListeners() {return this.applicationListeners;
}// 来自类 AbstractApplicationContext
Override
public void refresh() throws BeansException, IllegalStateException {synchronized (this.startupShutdownMonitor) {// Prepare this context for refreshing.prepareRefresh();// Tell the subclass to refresh the internal bean factory.ConfigurableListableBeanFactory beanFactory obtainFreshBeanFactory();// Prepare the bean factory for use in this context.prepareBeanFactory(beanFactory);try {// Allows post-processing of the bean factory in context subclasses.postProcessBeanFactory(beanFactory);// Invoke factory processors registered as beans in the context.invokeBeanFactoryPostProcessors(beanFactory);// Register bean processors that intercept bean creation.registerBeanPostProcessors(beanFactory);// Initialize message source for this context.initMessageSource();// Initialize event multicaster for this context.initApplicationEventMulticaster();// Initialize other special beans in specific context subclasses.onRefresh();// Check for listener beans and register them.registerListeners();// Instantiate all remaining (non-lazy-init) singletons.finishBeanFactoryInitialization(beanFactory);// Last step: publish corresponding event.// 发布 ContextRefreshedEvent、ServletWebServerInitializedEvent 事件// 会有一次 super.finishRefreshfinishRefresh();}catch (BeansException ex) {if (logger.isWarnEnabled()) {logger.warn(Exception encountered during context initialization - cancelling refresh attempt: ex);}// Destroy already created singletons to avoid dangling resources.destroyBeans();// Reset active flag.cancelRefresh(ex);// Propagate exception to caller.throw ex;}finally {// Reset common introspection caches in Springs core, since we// might not ever need metadata for singleton beans anymore...resetCommonCaches();}}
}刷新完后的 AnnotationConfigServletWebServerApplicationContext 将完全具有 BeanFactory 和 ApplicationContext 的功能剩下的就是一些收尾工作。
在完成刷新之后会发布 ContextRefreshedEvent、ServletWebServerInitializedEvent 事件。
4、callRunners
我们可以在Spring完全启动后通过实现 ApplicationRunner、CommandLineRunner 接口做一些事情。
private void callRunners(ApplicationContext context, ApplicationArguments args) {ListObject runners new ArrayList();runners.addAll(context.getBeansOfType(ApplicationRunner.class).values());runners.addAll(context.getBeansOfType(CommandLineRunner.class).values());AnnotationAwareOrderComparator.sort(runners);for (Object runner : new LinkedHashSet(runners)) {if (runner instanceof ApplicationRunner) {callRunner((ApplicationRunner) runner, args);}if (runner instanceof CommandLineRunner) {callRunner((CommandLineRunner) runner, args);}}
}再最后就是发布 ApplicationReadyEvent代表Spring已经完全启动了。
至此Spring Boot相关源码已梳理完毕下篇将着重分析Spring是如何处理一个请求的。
