In which class in the source code of spring-boot or spring is the application.yml file or application.properties processed?
CodePudding user response：
For spring boot (version 2.x) the application properties are loaded from the environment into the context via a PropertySourceLoader.
In for example the spring-boot-2.6.3.jar we can find the following file:
META-INF/spring.factories
# PropertySource Loaders
org.springframework.boot.env.PropertySourceLoader=\
org.springframework.boot.env.PropertiesPropertySourceLoader,\
org.springframework.boot.env.YamlPropertySourceLoader
Where PropertiesPropertySourceLoader loads .properties and .xml files, and YamlPropertySourceLoader loads .yml and .yaml.
These are loaded with the SpringFactoriesLoader, which we can see in action in org.springframework.boot.context.config.ConfigFileApplicationListener (deprecated) or org.springframework.boot.context.config.StandardConfigDataLocationResolver (via ConfigDataEnvironmentPostProcessor -> ConfigDataEnvironment -> ConfigDataLocationResolvers) :
this.propertySourceLoaders = SpringFactoriesLoader.loadFactories(PropertySourceLoader.class,
getClass().getClassLoader());
You can read in the ConfigFileApplicationListener JavaDoc that the properties are indeed loaded with this class:
EnvironmentPostProcessor that configures the context environment by loading properties from well known file locations. By default properties will be loaded from 'application.properties' and/or 'application.yml' files in the following locations: file:./config/ file:./config/*/ file:./ classpath:config/ classpath: ...
If you're interested in context loading from the environment in spring(boot), I suggest you setup your project with maven, download the sources jars, and have a look around in the mentioned factories file. You will find more relevant code in the org.springframework.boot.env and org.springframework.boot.context (config and properties) packages.
CodePudding user response：
You can find your application.yml or application.properties at the src/main/resources. You can have as many as possible configurations for your spring boot application for every case. Lets assume that you have 3 local-profiles like demo, production and server, so you made 3 configuration and assumingyou set for active profile the demo at the application.yml . I hope you get the idea. Its the first thing that actually is running before the springboot is up.