一、多Profile文件
Profile是Spring对不同环境提供不同配置功能的支持，可以通过激活、 指定参数等方式快速切换环境。
我们在主配置文件编写的时候，文件名可以是 application-{profile}.properties/yml ，
默认使用application.properties的配置；
- yml支持多文档块方式
server:
port: 8081
spring:
profiles:
active: prod
---
server:
port: 8083
spring:
profiles: dev
---
server:
port: 8084
spring:
profiles: prod #指定属于哪个环境
-
激活指定profile
-
在配置文件中指定 spring.profiles.active=dev
- 命令行：
java -jar spring-boot-02-config-0.0.1-SNAPSHOT.jar --spring.profiles.active=dev；
可以直接在测试的时候，配置传入命令行参数- 虚拟机参数；
-Dspring.profiles.active=dev二、配置文件加载位置
三、自动配置原理 Spring Boot 的功能官网文档
（1）配置文件能配置的属性参照spring boot 2.2.5官网
可以在application.properties文件内部application.yml，文件内部或命令行开关中指定各种属性。本附录提供了常见的Spring Boot属性列表以及对使用它们的基础类的引用。
- Spring Boot提供了各种具有高级值格式的转换机制，请务必查看属性转换部分。
（2）自动配置的原理：
- Spring Boot启动的时候加载主配置类，开启了自动配置功能 @SpringBootApplication下的@EnableAutoConfiguration
- @EnableAutoConfiguration的作用：
利用 AutoConfigurationImportSelector 选择器给容器导入一些组件，具体可以查看源码：selectImports()方法的内容：
- 获取候选配置
// 获取候选配置
List<String> configurations = this.getCandidateConfigurations(annotationMetadata, attributes);- 扫描所有jar包类路径下的 META-INF/spring.factories
List<String> configurations = SpringFactoriesLoader.loadFactoryNames(
this.getSpringFactoriesLoaderFactoryClass(),
this.getBeanClassLoader());- 把扫描到的这些文件的内容包装成properties对象中
Properties properties = PropertiesLoaderUtils.loadProperties(resource);- 从Properties中获取到 EnableAutoConfiguration.class 类（类名）的值,然后把他们添加到容器中。
- 将类路径下的 META-INF/spring.factories 里面配置的所有 EnableAutoConfiguration的值加入到容器中。
# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\
org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration,\
org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration,\
org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,\
org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration,\
org.springframework.boot.autoconfigure.cloud.CloudServiceConnectorsAutoConfiguration,\
org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,\
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration,\
org.springframework.boot.autoconfigure.couchbase.CouchbaseAutoConfiguration,\
org.springframework.boot.autoconfigure.dao.PersistenceExceptionTranslationAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveRestClientAutoConfiguration,\
org.springframework.boot.autoconfigure.data.jdbc.JdbcRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.ldap.LdapRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.solr.SolrRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.rest.RepositoryRestMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.data.web.SpringDataWebAutoConfiguration,\
org.springframework.boot.autoconfigure.elasticsearch.jest.JestAutoConfiguration,\
org.springframework.boot.autoconfigure.elasticsearch.rest.RestClientAutoConfiguration,\
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration,\
org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration,\
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration,\
org.springframework.boot.autoconfigure.h2.H2ConsoleAutoConfiguration,\
org.springframework.boot.autoconfigure.hateoas.HypermediaAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastJpaDependencyAutoConfiguration,\
org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration,\
org.springframework.boot.autoconfigure.http.codec.CodecsAutoConfiguration,\
org.springframework.boot.autoconfigure.influx.InfluxDbAutoConfiguration,\
org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration,\
org.springframework.boot.autoconfigure.integration.IntegrationAutoConfiguration,\
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.XADataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JmsAutoConfiguration,\
org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JndiConnectionFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.activemq.ActiveMQAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.artemis.ArtemisAutoConfiguration,\
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration,\
org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration,\
org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration,\
org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration,\
org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapAutoConfiguration,\
org.springframework.boot.autoconfigure.ldap.LdapAutoConfiguration,\
org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderValidatorAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.MongoReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration,\
org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration,\
org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketMessagingAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketRequesterAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketServerAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketStrategiesAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.UserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityFilterAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveUserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.security.rsocket.RSocketSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyAutoConfiguration,\
org.springframework.boot.autoconfigure.sendgrid.SendGridAutoConfiguration,\
org.springframework.boot.autoconfigure.session.SessionAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.client.servlet.OAuth2ClientAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.client.reactive.ReactiveOAuth2ClientAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.resource.servlet.OAuth2ResourceServerAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.resource.reactive.ReactiveOAuth2ResourceServerAutoConfiguration,\
org.springframework.boot.autoconfigure.solr.SolrAutoConfiguration,\
org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration,\
org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration,\
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.jta.JtaAutoConfiguration,\
org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration,\
org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.HttpHandlerAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.ReactiveWebServerFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.error.ErrorWebFluxAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.function.client.ClientHttpConnectorAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.reactive.WebSocketReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketServletAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketMessagingAutoConfiguration,\
org.springframework.boot.autoconfigure.webservices.WebServicesAutoConfiguration,\
org.springframework.boot.autoconfigure.webservices.client.WebServiceTemplateAutoConfiguration
# Failure analyzers
org.springframework.boot.diagnostics.FailureAnalyzer=\
org.springframework.boot.autoconfigure.diagnostics.analyzer.NoSuchBeanDefinitionFailureAnalyzer,\
org.springframework.boot.autoconfigure.flyway.FlywayMigrationScriptMissingFailureAnalyzer,\
org.springframework.boot.autoconfigure.jdbc.DataSourceBeanCreationFailureAnalyzer,\
org.springframework.boot.autoconfigure.jdbc.HikariDriverConfigurationFailureAnalyzer,\
org.springframework.boot.autoconfigure.session.NonUniqueSessionRepositoryFailureAnalyzer
# Template availability providers
org.springframework.boot.autoconfigure.template.TemplateAvailabilityProvider=\
org.springframework.boot.autoconfigure.freemarker.FreeMarkerTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.mustache.MustacheTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.web.servlet.JspTemplateAvailabilityProvider每一个这样 XXXAutoConfiguration 类都是容器中的一个组件，都加入到容器中，用他们实现自动配置。
每一个自动配置类 进行自动配置功能
以 HttpEncodingAutoConfiguration 为例解析自动配置原理
//表示这是一个配置类
@Configuration(
proxyBeanMethods = false
)
//启动指定类的ConfigurationProperties功能；
//将配置文件中对应的值和HttpEncodingProperties绑定起来；并把HttpEncodingProperties加入到ioc容器中
@EnableConfigurationProperties({HttpProperties.class})
//Spring底层@Conditional注解（Spring注解版），根据不同的条件，
//如果满足指定的条件，整个配置类里面的配置就会生效； 判断当前应用是否是web应用，如果是，当前配置类生效
@ConditionalOnWebApplication(
type = Type.SERVLET
)
//判断当前项目有没有这个类CharacterEncodingFilter；SpringMVC中进行乱码解决的过滤器；
@ConditionalOnClass({CharacterEncodingFilter.class})
//判断配置文件中是否存在某个配置 spring.http.encoding.enabled；如果不存在，判断也是成立的
@ConditionalOnProperty(
prefix = "spring.http.encoding",
value = {"enabled"},
matchIfMissing = true
)
//即使我们配置文件中不配置pring.http.encoding.enabled=true，也是默认生效的；
public class HttpEncodingAutoConfiguration {
//他已经和SpringBoot的配置文件映射了
private final Encoding properties;
//只有一个有参构造器的情况下，参数的值就会从容器中拿
public HttpEncodingAutoConfiguration(HttpProperties properties) {
this.properties = properties.getEncoding();
}
@Bean //给容器中添加一个组件，这个组件的某些值需要从properties中获取
@ConditionalOnMissingBean //判断容器没有这个组件？
public CharacterEncodingFilter characterEncodingFilter() {
CharacterEncodingFilter filter = new OrderedCharacterEncodingFilter();
filter.setEncoding(this.properties.getCharset().name());
filter.setForceRequestEncoding(this.properties.shouldForce(
org.springframework.boot.autoconfigure.http.HttpProperties.Encoding.Type.REQUEST));
filter.setForceResponseEncoding(this.properties.shouldForce(
org.springframework.boot.autoconfigure.http.HttpProperties.Encoding.Type.RESPONSE));
return filter;
}
}根据当前不同的条件判断，决定这个配置类是否生效？
一但这个配置类生效；这个配置类就会给容器中添加各种组件；这些组件的属性是从对应的properties类中获取的，这些类里面的每一个属性又是和配置文件绑定的；
5）所有在配置文件中能配置的属性都是在xxxxProperties类中封装‘；配置文件能配置什么就可以参照某个功能对应的这个属性类
@ConfigurationProperties( //从配置文件中获取指定的值和bean的属性进行绑定
prefix = "spring.http"
)
public class HttpProperties {
private boolean logRequestDetails;
private final HttpProperties.Encoding encoding = new HttpProperties.Encoding();精髓：
- SpringBoot启动会加载大量的自动配置类
- 我们看我们需要的功能有没有SpringBoot默认写好的自动配置类；
- 我们再来看这个自动配置类中到底配置了哪些组件；（只要我们要用的组件有，我们就不需要再来配置了）
- 给容器中自动配置类添加组件的时候，会从properties类中获取某些属性。我们就可以在配置文件中指定这些属性的值；
- xxxxAutoConfigurartion：自动配置类；
- 给容器中添加组件
- xxxxProperties:封装配置文件中相关属性；
@Conditional派生注解（Spring注解版原生的@Conditional作用）
作用：必须是@Conditional指定的条件成立，才给容器中添加组件，配置配里面的所有内容才生效；
| @Conditional扩展注解 | 作用（判断是否满足当前指定条件） |
|---|---|
| @ConditionalOnJava | 系统的java版本是否符合要求 |
| @ConditionalOnBean | 容器中存在指定Bean； |
| @ConditionalOnMissingBean | 容器中不存在指定Bean； |
| @ConditionalOnExpression | 满足SpEL表达式指定 |
| @ConditionalOnClass | 系统中有指定的类 |
| @ConditionalOnMissingClass | 系统中没有指定的类 |
| @ConditionalOnSingleCandidate | 容器中只有一个指定的Bean，或者这个Bean是首选Bean |
| @ConditionalOnProperty | 系统中指定的属性是否有指定的值 |
| @ConditionalOnResource | 类路径下是否存在指定资源文件 |
| @ConditionalOnWebApplication | 当前是web环境 |
| @ConditionalOnNotWebApplication | 当前不是web环境 |
| @ConditionalOnJndi | JNDI存在指定项 |
自动配置类必须在一定的条件下才能生效；
Q: 我们怎么知道哪些自动配置类生效 ?
我们可以通过启用 debug=true属性；来让控制台打印自动配置报告==，这样我们就可以很方便的知道哪些自动配置类生效；
下面是生成的支持和不支持的自动配置类报告
============================
CONDITIONS EVALUATION REPORT
============================
Positive matches:
-----------------
AopAutoConfiguration matched:
- @ConditionalOnProperty (spring.aop.auto=true) matched (OnPropertyCondition)
AopAutoConfiguration.ClassProxyingConfiguration matched:
- @ConditionalOnMissingClass did not find unwanted class 'org.aspectj.weaver.Advice' (OnClassCondition)
- @ConditionalOnProperty (spring.aop.proxy-target-class=true) matched (OnPropertyCondition)
DispatcherServletAutoConfiguration matched:
- @ConditionalOnClass found required class 'org.springframework.web.servlet.DispatcherServlet' (OnClassCondition)
- found 'session' scope (OnWebApplicationCondition)
DispatcherServletAutoConfiguration.DispatcherServletConfiguration matched:
- @ConditionalOnClass found required class 'javax.servlet.ServletRegistration' (OnClassCondition)
- Default DispatcherServlet did not find dispatcher servlet beans (DispatcherServletAutoConfiguration.DefaultDispatcherServletCondition)
Negative matches:
-----------------
ActiveMQAutoConfiguration:
Did not match:
- @ConditionalOnClass did not find required class 'javax.jms.ConnectionFactory' (OnClassCondition)
AopAutoConfiguration.AspectJAutoProxyingConfiguration:
Did not match:
- @ConditionalOnClass did not find required class 'org.aspectj.weaver.Advice' (OnClassCondition)
ArtemisAutoConfiguration:
Did not match:
- @ConditionalOnClass did not find required class 'javax.jms.ConnectionFactory' (OnClassCondition)
