关于后端:Spring-源码解析十四SpringBoot-Autoconfigure-初始化应用时加载的组件

这些组件定义在 spring.factories
中

# 初始化器
org.springframework.context.ApplicationContextInitializer=\
org.springframework.boot.autoconfigure.SharedMetadataReaderFactoryContextInitializer,\
org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener

# 利用事件监听器
org.springframework.context.ApplicationListener=\
org.springframework.boot.autoconfigure.BackgroundPreinitializer

# 主动配置导入监听器
org.springframework.boot.autoconfigure.AutoConfigurationImportListener=\
org.springframework.boot.autoconfigure.condition.ConditionEvaluationReportAutoConfigurationImportListener

# 主动配置导入过滤器
org.springframework.boot.autoconfigure.AutoConfigurationImportFilter=\
org.springframework.boot.autoconfigure.condition.OnBeanCondition,\
org.springframework.boot.autoconfigure.condition.OnClassCondition,\
org.springframework.boot.autoconfigure.condition.OnWebApplicationCondition

# 主动配置
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.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

# 失败分析器
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

# 查看模板可用提供器
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.context.ApplicationContextInitializer=\
org.springframework.boot.autoconfigure.SharedMetadataReaderFactoryContextInitializer,\
org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener

SharedMetadataReaderFactoryContextInitializer
的次要性能是提供一个共享的缓存元信息读取工厂

class SharedMetadataReaderFactoryContextInitializer
        implements ApplicationContextInitializer<ConfigurableApplicationContext>, Ordered {
    // 初始化
    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {BeanFactoryPostProcessor postProcessor = new CachingMetadataReaderFactoryPostProcessor(applicationContext);
        applicationContext.addBeanFactoryPostProcessor(postProcessor);
    }

    static class CachingMetadataReaderFactoryPostProcessor
            implements BeanDefinitionRegistryPostProcessor, PriorityOrdered {
        // 注册 bean 定义
        @Override
        public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
            // 注册 bean 定义注册器
            register(registry);
            // 配置 @Configuration bean
            configureConfigurationClassPostProcessor(registry);
        }

        // 注册 bean 定义注册器
        private void register(BeanDefinitionRegistry registry) {
            BeanDefinition definition = BeanDefinitionBuilder
                    .genericBeanDefinition(SharedMetadataReaderFactoryBean.class, SharedMetadataReaderFactoryBean::new)
                    .getBeanDefinition();
            // 注册为 "org.springframework.boot.autoconfigure.internalCachingMetadataReaderFactory" 名字
            registry.registerBeanDefinition(BEAN_NAME, definition);
        }

        // 配置 @Configuration bean
        private void configureConfigurationClassPostProcessor(BeanDefinitionRegistry registry) {
            try {
                // 配置 bean "org.springframework.context.annotation.internalConfigurationAnnotationProcessor"
                configureConfigurationClassPostProcessor(registry.getBeanDefinition(AnnotationConfigUtils.CONFIGURATION_ANNOTATION_PROCESSOR_BEAN_NAME));
            }
            catch (NoSuchBeanDefinitionException ex) {}}
    }
}

ConditionEvaluationReportLoggingListener
的次要性能是输入日志到文件

org.springframework.context.ApplicationListener=\
org.springframework.boot.autoconfigure.BackgroundPreinitializer

BackgroundPreinitializer
的次要性能是初始化数据转换与编码等服务

public class BackgroundPreinitializer implements ApplicationListener<SpringApplicationEvent> {
    @Override
    public void onApplicationEvent(SpringApplicationEvent event) {
        // ... 代码省略

        if (event instanceof ApplicationEnvironmentPreparedEvent
                && preinitializationStarted.compareAndSet(false, true)) {performPreinitialization();
        }
        if ((event instanceof ApplicationReadyEvent || event instanceof ApplicationFailedEvent)
                && preinitializationStarted.get()) {
            try {preinitializationComplete.await();
            }
            catch (InterruptedException ex) {Thread.currentThread().interrupt();}
        }
    }

    // 初始化其余组件
    private void performPreinitialization() {
        try {Thread thread = new Thread(new Runnable() {

                @Override
                public void run() {
                    // 初始化数据转换服务，DefaultFormattingConversionService
                    runSafely(new ConversionServiceInitializer());
                    // 初始化数据验证服务，Validation.byDefaultProvider()
                    runSafely(new ValidationInitializer());
                    // 初始化音讯转换服务，AllEncompassingFormHttpMessageConverter
                    runSafely(new MessageConverterInitializer());
                    // 初始化 JSON 服务，Jackson2ObjectMapperBuilder
                    runSafely(new JacksonInitializer());
                    // 初始化字符编码服务，StandardCharsets
                    runSafely(new CharsetInitializer());
                    preinitializationComplete.countDown();}

                public void runSafely(Runnable runnable) {
                    try {runnable.run();
                    }
                    catch (Throwable ex) {}}

            }, "background-preinit");
            thread.start();}
        catch (Exception ex) {// ... 代码省略}
    }

    private static class MessageConverterInitializer implements Runnable {
        @Override
        public void run() {new AllEncompassingFormHttpMessageConverter();
        }
    }

    private static class ValidationInitializer implements Runnable {
        @Override
        public void run() {Configuration<?> configuration = Validation.byDefaultProvider().configure();
            configuration.buildValidatorFactory().getValidator();
        }
    }

    private static class JacksonInitializer implements Runnable {
        @Override
        public void run() {Jackson2ObjectMapperBuilder.json().build();}
    }

    private static class ConversionServiceInitializer implements Runnable {
        @Override
        public void run() {new DefaultFormattingConversionService();
        }
    }

    private static class CharsetInitializer implements Runnable {
        @Override
        public void run() {StandardCharsets.UTF_8.name();
        }
    }
}

org.springframework.boot.autoconfigure.AutoConfigurationImportListener=\
org.springframework.boot.autoconfigure.condition.ConditionEvaluationReportAutoConfigurationImportListener

ConditionEvaluationReportAutoConfigurationImportListener
的次要性能是从 Report 中读取后果

org.springframework.boot.autoconfigure.AutoConfigurationImportFilter=\
org.springframework.boot.autoconfigure.condition.OnBeanCondition,\
org.springframework.boot.autoconfigure.condition.OnClassCondition,\
org.springframework.boot.autoconfigure.condition.OnWebApplicationCondition

OnBeanCondition
的次要性能是解决注解 @ConditionalOnBean、@ConditionalOnMissingBean、@ConditionalOnSingleCandidate，按条件动静载入 bean

@ConditionOnBean 判断条件 bean 存在，注入当下注解的 bean
@ConditionOnMissingBean 判断条件 bean 不存在，才注入当下注解的 bean
@ConditionalOnSingleCandidate 判断条件 bean 只能有一个实例或多个但只有一个 primary 实例，才注入当下注解的 bean

先来看看继承关系

- SpringBootCondition
  - FilteringSpringBootCondition
    - OnBeanCondition

SpringBootCondition
是用条件来查看组件的根底类

public abstract class SpringBootCondition implements Condition {
    // 元信息代表的组件是否匹配
    @Override
    public final boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        // 获取类名或办法名
        String classOrMethodName = getClassOrMethodName(metadata);
        try {
            // 获取匹配后果
            ConditionOutcome outcome = getMatchOutcome(context, metadata);

            // ... 代码省略

            // 返回是否匹配
            return outcome.isMatch();}
        catch (NoClassDefFoundError ex) {// ... 代码省略}

        // ... 代码省略
    }

    // 获取匹配后果，由子类实现
    public abstract ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata);
}

FilteringSpringBootCondition
的次要性能是增加过滤性能

abstract class FilteringSpringBootCondition extends SpringBootCondition
        implements AutoConfigurationImportFilter, BeanFactoryAware, BeanClassLoaderAware {
    // 元信息代表的组件是否匹配
    @Override
    public boolean[] match(String[] autoConfigurationClasses, AutoConfigurationMetadata autoConfigurationMetadata) {
        // 获取后果
        ConditionOutcome[] outcomes = getOutcomes(autoConfigurationClasses, autoConfigurationMetadata);
        boolean[] match = new boolean[outcomes.length];
        for (int i = 0; i < outcomes.length; i++) {
            // 如果返回为 null 或 true，则示意匹配
            match[i] = (outcomes[i] == null || outcomes[i].isMatch());
            // ... 代码省略
        }
        return match;
    }

    // 获取后果，由子类实现
    protected abstract ConditionOutcome[] getOutcomes(String[] autoConfigurationClasses,
            AutoConfigurationMetadata autoConfigurationMetadata);
}

SpringBootCondition
的次要性能是解决注解 @ConditionalOnBean、@ConditionalOnMissingBean、@ConditionalOnSingleCandidate，按条件动静载入 bean

class OnBeanCondition extends FilteringSpringBootCondition implements ConfigurationCondition {
    // 获取后果
    @Override
    protected final ConditionOutcome[] getOutcomes(String[] autoConfigurationClasses,
            AutoConfigurationMetadata autoConfigurationMetadata) {
        // 后果集
        ConditionOutcome[] outcomes = new ConditionOutcome[autoConfigurationClasses.length];
        for (int i = 0; i < outcomes.length; i++) {
            // 主动配置类
            String autoConfigurationClass = autoConfigurationClasses[i];
            if (autoConfigurationClass != null) {
                // 获取 ConditionalOnBean 的 bean 类型
                Set<String> onBeanTypes = autoConfigurationMetadata.getSet(autoConfigurationClass, "ConditionalOnBean");
                // 确定有没有 ConditionalOnBean 的 bean 类型
                outcomes[i] = getOutcome(onBeanTypes, ConditionalOnBean.class);
                if (outcomes[i] == null) {
                    // 获取 ConditionalOnSingleCandidate 的 bean 类型
                    Set<String> onSingleCandidateTypes = autoConfigurationMetadata.getSet(autoConfigurationClass,
                            "ConditionalOnSingleCandidate");
                    // 确定有没有 ConditionalOnSingleCandidate 的 bean 类型
                    outcomes[i] = getOutcome(onSingleCandidateTypes, ConditionalOnSingleCandidate.class);
                }
            }
        }
        return outcomes;
    }
}

class OnBeanCondition extends FilteringSpringBootCondition implements ConfigurationCondition {
    // 获取匹配后果
    @Override
    public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
        // 匹配信息
        ConditionMessage matchMessage = ConditionMessage.empty();
        // 元信息中的注解
        MergedAnnotations annotations = metadata.getAnnotations();
        // 有 @ConditionalOnBean 注解
        if (annotations.isPresent(ConditionalOnBean.class)) {
            // 创立 ConditionalOnBean 的匹配规范对象
            Spec<ConditionalOnBean> spec = new Spec<>(context, metadata, annotations, ConditionalOnBean.class);
            // 获取匹配的 bean
            MatchResult matchResult = getMatchingBeans(context, spec);
            // 如果一个都没有匹配到
            if (!matchResult.isAllMatched()) {
                // 返回匹配不到的信息
                String reason = createOnBeanNoMatchReason(matchResult);
                return ConditionOutcome.noMatch(spec.message().because(reason));
            }
            // 匹配到了，持续
            matchMessage = spec.message(matchMessage).found("bean", "beans").items(Style.QUOTE,
                    matchResult.getNamesOfAllMatches());
        }
        // 有 @ConditionalOnSingleCandidate 注解
        if (metadata.isAnnotated(ConditionalOnSingleCandidate.class.getName())) {
            // 创立 ConditionalOnSingleCandidate 的匹配规范对象
            Spec<ConditionalOnSingleCandidate> spec = new SingleCandidateSpec(context, metadata, annotations);
            // 获取匹配的 bean
            MatchResult matchResult = getMatchingBeans(context, spec);
            // 如果一个都没有匹配到
            if (!matchResult.isAllMatched()) {
                // 返回匹配不到的信息
                return ConditionOutcome.noMatch(spec.message().didNotFind("any beans").atAll());
            }
            // 匹配到多个 bean，但没有 primary bean
            else if (!hasSingleAutowireCandidate(context.getBeanFactory(), matchResult.getNamesOfAllMatches(),
                    spec.getStrategy() == SearchStrategy.ALL)) {
                // 返回匹配到多个的信息
                return ConditionOutcome.noMatch(spec.message().didNotFind("a primary bean from beans")
                        .items(Style.QUOTE, matchResult.getNamesOfAllMatches()));
            }
            // 匹配到了，持续
            matchMessage = spec.message(matchMessage).found("a primary bean from beans").items(Style.QUOTE,
                    matchResult.getNamesOfAllMatches());
        }
        // 有 @ConditionalOnMissingBean 注解
        if (metadata.isAnnotated(ConditionalOnMissingBean.class.getName())) {
            // 创立 ConditionalOnMissingBean 的匹配规范对象
            Spec<ConditionalOnMissingBean> spec = new Spec<>(context, metadata, annotations,
                    ConditionalOnMissingBean.class);
            // 获取匹配的 bean
            MatchResult matchResult = getMatchingBeans(context, spec);
            // 如果匹配到了
            if (matchResult.isAnyMatched()) {
                // 返回匹配到了的信息
                String reason = createOnMissingBeanNoMatchReason(matchResult);
                return ConditionOutcome.noMatch(spec.message().because(reason));
            }
            // 匹配不到，持续
            matchMessage = spec.message(matchMessage).didNotFind("any beans").atAll();}
        return ConditionOutcome.match(matchMessage);
    }
}

OnClassCondition
的次要性能是解决注解 @ConditionalOnClass、@ConditionalOnMissingClass，按条件动静载入 bean

@ConditionalOnClass 判断条件类存在，注入当下注解的 bean
@ConditionalOnMissingClass 判断条件类不存在，才注入当下注解的 bean

class OnClassCondition extends FilteringSpringBootCondition {
    // 获取后果
    @Override
    protected final ConditionOutcome[] getOutcomes(String[] autoConfigurationClasses,
            AutoConfigurationMetadata autoConfigurationMetadata) {
        // ... 代码省略

        OutcomesResolver outcomesResolver = new StandardOutcomesResolver(autoConfigurationClasses, 0,
                autoConfigurationClasses.length, autoConfigurationMetadata, getBeanClassLoader());
        // 获取 ConditionalOnClass 的输入
        return outcomesResolver.resolveOutcomes();}

    // 获取匹配后果
    @Override
    public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {ClassLoader classLoader = context.getClassLoader();
        // 匹配信息
        ConditionMessage matchMessage = ConditionMessage.empty();
        // 获取标记有 @ConditionalOnClass 注解的类
        List<String> onClasses = getCandidates(metadata, ConditionalOnClass.class);
        if (onClasses != null) {List<String> missing = filter(onClasses, ClassNameFilter.MISSING, classLoader);
            // 类不存在，返回
            if (!missing.isEmpty()) {return ConditionOutcome.noMatch(ConditionMessage.forCondition(ConditionalOnClass.class)
                        .didNotFind("required class", "required classes").items(Style.QUOTE, missing));
            }
            // 类存在，持续
            matchMessage = matchMessage.andCondition(ConditionalOnClass.class)
                    .found("required class", "required classes")
                    .items(Style.QUOTE, filter(onClasses, ClassNameFilter.PRESENT, classLoader));
        }
        // 获取标记有 @ConditionalOnMissingClass 注解的类
        List<String> onMissingClasses = getCandidates(metadata, ConditionalOnMissingClass.class);
        if (onMissingClasses != null) {List<String> present = filter(onMissingClasses, ClassNameFilter.PRESENT, classLoader);
            // 类存在，返回
            if (!present.isEmpty()) {return ConditionOutcome.noMatch(ConditionMessage.forCondition(ConditionalOnMissingClass.class)
                        .found("unwanted class", "unwanted classes").items(Style.QUOTE, present));
            }
            // 类不存在，持续
            matchMessage = matchMessage.andCondition(ConditionalOnMissingClass.class)
                    .didNotFind("unwanted class", "unwanted classes")
                    .items(Style.QUOTE, filter(onMissingClasses, ClassNameFilter.MISSING, classLoader));
        }
        return ConditionOutcome.match(matchMessage);
    }

}

OnWebApplicationCondition
的次要性能是解决注解 @ConditionalOnWebApplication、@ConditionalOnNotWebApplication，按条件动静载入 bean

@ConditionalOnWebApplication 判断利用时 Web 利用时，注入当下注解的 bean
@ConditionalOnNotWebApplication 判断利用时不是 Web 利用时，才注入当下注解的 bean

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.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

SpringApplicationAdminJmxAutoConfiguration
AopAutoConfiguration
RabbitAutoConfiguration
BatchAutoConfiguration
CacheAutoConfiguration
CassandraAutoConfiguration
ConfigurationPropertiesAutoConfiguration
LifecycleAutoConfiguration
MessageSourceAutoConfiguration
PropertyPlaceholderAutoConfiguration
CouchbaseAutoConfiguration
PersistenceExceptionTranslationAutoConfiguration
CassandraDataAutoConfiguration
CassandraReactiveDataAutoConfiguration
CassandraReactiveRepositoriesAutoConfiguration
CassandraRepositoriesAutoConfiguration
CouchbaseDataAutoConfiguration
CouchbaseReactiveDataAutoConfiguration
CouchbaseReactiveRepositoriesAutoConfiguration
CouchbaseRepositoriesAutoConfiguration
ElasticsearchDataAutoConfiguration
ElasticsearchRepositoriesAutoConfiguration
ReactiveElasticsearchRepositoriesAutoConfiguration
ReactiveElasticsearchRestClientAutoConfiguration
JdbcRepositoriesAutoConfiguration
JpaRepositoriesAutoConfiguration
LdapRepositoriesAutoConfiguration
MongoDataAutoConfiguration
MongoReactiveDataAutoConfiguration
MongoReactiveRepositoriesAutoConfiguration
MongoRepositoriesAutoConfiguration
Neo4jDataAutoConfiguration
Neo4jReactiveDataAutoConfiguration
Neo4jReactiveRepositoriesAutoConfiguration
Neo4jRepositoriesAutoConfiguration
R2dbcDataAutoConfiguration
R2dbcRepositoriesAutoConfiguration
RedisAutoConfiguration
RedisReactiveAutoConfiguration
RedisRepositoriesAutoConfiguration
RepositoryRestMvcAutoConfiguration
SpringDataWebAutoConfiguration
ElasticsearchRestClientAutoConfiguration
FlywayAutoConfiguration
FreeMarkerAutoConfiguration
GroovyTemplateAutoConfiguration
GsonAutoConfiguration
H2ConsoleAutoConfiguration
HypermediaAutoConfiguration
HazelcastAutoConfiguration
HazelcastJpaDependencyAutoConfiguration
HttpMessageConvertersAutoConfiguration
CodecsAutoConfiguration
InfluxDbAutoConfiguration
ProjectInfoAutoConfiguration
IntegrationAutoConfiguration
JacksonAutoConfiguration
DataSourceAutoConfiguration
JdbcTemplateAutoConfiguration
JndiDataSourceAutoConfiguration
XADataSourceAutoConfiguration
DataSourceTransactionManagerAutoConfiguration
JmsAutoConfiguration
JmxAutoConfiguration
JndiConnectionFactoryAutoConfiguration
ActiveMQAutoConfiguration
ArtemisAutoConfiguration
JerseyAutoConfiguration
JooqAutoConfiguration
JsonbAutoConfiguration
KafkaAutoConfiguration
ApplicationAvailabilityAutoConfiguration
EmbeddedLdapAutoConfiguration
LdapAutoConfiguration
LiquibaseAutoConfiguration
MailSenderAutoConfiguration
MailSenderValidatorAutoConfiguration
EmbeddedMongoAutoConfiguration
MongoAutoConfiguration
MongoReactiveAutoConfiguration
MustacheAutoConfiguration
Neo4jAutoConfiguration
HibernateJpaAutoConfiguration
QuartzAutoConfiguration
R2dbcAutoConfiguration
R2dbcTransactionManagerAutoConfiguration
RSocketMessagingAutoConfiguration
RSocketRequesterAutoConfiguration
RSocketServerAutoConfiguration
RSocketStrategiesAutoConfiguration
SecurityAutoConfiguration
UserDetailsServiceAutoConfiguration
SecurityFilterAutoConfiguration
ReactiveSecurityAutoConfiguration
ReactiveUserDetailsServiceAutoConfiguration
RSocketSecurityAutoConfiguration
Saml2RelyingPartyAutoConfiguration
SendGridAutoConfiguration
SessionAutoConfiguration
OAuth2ClientAutoConfiguration
ReactiveOAuth2ClientAutoConfiguration
OAuth2ResourceServerAutoConfiguration
ReactiveOAuth2ResourceServerAutoConfiguration
SolrAutoConfiguration
TaskExecutionAutoConfiguration
TaskSchedulingAutoConfiguration
ThymeleafAutoConfiguration
TransactionAutoConfiguration
JtaAutoConfiguration
ValidationAutoConfiguration
RestTemplateAutoConfiguration
EmbeddedWebServerFactoryCustomizerAutoConfiguration
HttpHandlerAutoConfiguration
ReactiveWebServerFactoryAutoConfiguration
WebFluxAutoConfiguration
ErrorWebFluxAutoConfiguration
ClientHttpConnectorAutoConfiguration
WebClientAutoConfiguration
DispatcherServletAutoConfiguration
ServletWebServerFactoryAutoConfiguration
ErrorMvcAutoConfiguration
HttpEncodingAutoConfiguration
MultipartAutoConfiguration
WebMvcAutoConfiguration
WebSocketReactiveAutoConfiguration
WebSocketServletAutoConfiguration
WebSocketMessagingAutoConfiguration
WebServicesAutoConfiguration
WebServiceTemplateAutoConfiguration

以上的类都是通过 application*.yaml 中的属性配置主动装载成 bean。这些类比拟多，能够自行摸索

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

RedisUrlSyntaxFailureAnalyzer
Redis url 语法错误
NoSuchBeanDefinitionFailureAnalyzer
没有 bean 定义
FlywayMigrationScriptMissingFailureAnalyzer
Flyway 没有可用的 sql 脚本
DataSourceBeanCreationFailureAnalyzer
数据库源 bean 创立失败
HikariDriverConfigurationFailureAnalyzer
HikariCP 配置失败
ConnectionFactoryBeanCreationFailureAnalyzer
ConnectionFactory bean 创立失败
NonUniqueSessionRepositoryFailureAnalyzer
多个 Spring Session 谬误

这些类都比较简单，能够自行摸索

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

FreeMarkerTemplateAvailabilityProvider
FreeMarker 模板查看
MustacheTemplateAvailabilityProvider
Mustache 模板查看
GroovyTemplateAvailabilityProvider
Groovy 模板查看
ThymeleafTemplateAvailabilityProvider
Thymeleaf 模板查看
JspTemplateAvailabilityProvider
Jsp 模板查看

这些类都比较简单，能够自行摸索

更多博客，查看 https://github.com/senntyou/blogs

作者：深予之 (@senntyou)

版权申明：自在转载 - 非商用 - 非衍生 - 放弃署名（创意共享 3.0 许可证）

关于后端:Spring-源码解析十四SpringBoot-Autoconfigure-初始化应用时加载的组件

Spring 源码解析十四：SpringBoot Autoconfigure 初始化利用时加载的组件

1. 初始化器

1.1. SharedMetadataReaderFactoryContextInitializer

1.2. ConditionEvaluationReportLoggingListener

2. 利用事件监听器

3. 主动配置导入监听器

4. 主动配置导入过滤器

4.1. OnBeanCondition

4.1.1. SpringBootCondition

4.1.2. FilteringSpringBootCondition

4.1.3. SpringBootCondition

4.2. OnClassCondition

4.3. OnWebApplicationCondition

5. 主动配置

6. 失败分析器

7. 查看模板可用提供器

后续