1. Parent project inherited by springboot
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId> // Click to track dependencies
<version>2.2.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
Yml is loaded with properties first, which means that properties will override the configuration of yml.
application.yml->application.yaml->application.properties
The parent project has tracking for configuration files
And then inherit the parent project
The parent project has a lot of version control
2. @SpringBootApplication bottom layer
Enter @springbootapplication
1.@springbootconfiguration contains @configuration: spring configuration reference
This annotation is mainly used to automatically scan each controller service dao layer. There is no need to manually write and scan like spring.
3.@EnableAutoConfiguration: automatic configuration
Enter this annotation
Enter the AtuoconfigurationImportSelector class, find getCandidateConfigurations, and observe that the return value is configurations. It can be seen that the returned configuration collection is
Enter the method getCandidateConfigurations, which loads certain configurations
Observe the message: No auto configuration classes found in META-INF/spring.factories. If you are using a custom packaging, make sure that file is correct.Translation: Autoconfiguration class not found in META-INF/spring.factories. If using custom packaging, make sure the file is correct.
This means that generally our automatic configuration files are placed under META-INF/spring.factories
The spring.factorie is the referenced configuration file under the package
Contents of the package
Automatically configured function classes
We select an automatic configuration class to search for, for example:
ServerProperties.class: Now we can see some configuration properties, prefixed by perfix, for example: server.port
Now we have only found the source of configuration properties, not some automatic configuration data. Its configuration content is:
By referencing the json configuration data, we can see that the default automatic configuration port is server.port=8080
