Spring boot annotations

@EnableAutoConfiguration
With this annotation, spring boot will guess what kind of spring application you will be developing based on the jar dependencies in Classpat. For example: Spring-boot-starter-web this dependency, then Springboot will automatically embed the relevant dependencies of Tomcat and Springmvc, and start as a Web application at startup. The corresponding configuration parameters are found, and if not, the default values are used. such as: server.port=8080;

@Component
It is a class-level annotation. This class is automatically detected when the application is configured through annotations or when the XML configuration is scanned. According to some special types of annotations derived from @component, such as: Repository, Service, Controller, are component.

@Import
The configuration class for importing @configuration is equivalent to the import tag in XML.

@Configuration
Startup configuration parameters, equivalent to the <beans> in XML

@ConfigurationProperties
configurationproperties Specifies the configuration parameters in the APPLICATION.YML. and loaded into the corresponding class.
such as: @ConfigurationProperties (prefix = "Spring.datasource");

@EnableConfigurationPropertiesbr/>enableconfigurationproperties Specifies the class that is annotated by @configurationproperties, Make it effective.
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@ConditionalOnClassbr/> This type takes effect when there is a class specified in the @conditionalonclass annotation in classpath.
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@Configuration@ConditionalOnClass({ DataSource.class, EmbeddedDatabaseType.class })@EnableConfigurationProperties(DataSourceProperties.class)@Import({ DataSourcePoolMetadataProvidersConfiguration.class,        

@ConditionalOnMissingBeanbr/> and @conditionalonclass, in contrast, when there is no annotation specified in the Classpath class. This configuration class is in effect.
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    @Configuration    @Conditional(PooledDataSourceCondition.class)    @ConditionalOnMissingBean({ DataSource.class, XADataSource.class })    @Import({ DataSourceConfiguration.Hikari.class, DataSourceConfiguration.Tomcat.class,            DataSourceConfiguration.Dbcp2.class, DataSourceConfiguration.Generic.class,            DataSourceJmxConfiguration.class })    protected static class PooledDataSourceConfiguration {    }

@Conditional
As with @conditionalonclass, it's just a custom implementation.

@ConditionalOnProperty
This class takes effect when there are corresponding parameters in the Application.yaml;
Such as:@ConditionalOnProperty(prefix = "spring.datasource", name = "type")

Spring boot annotations