spring-boot Package scanning Creating your own auto-configuration
Example
Spring boot is based on a lot of pre-made auto-configuration parent projects. You should already be familiar with spring boot starter projects.
You can easily create your own starter project by doing the following easy steps:
- Create some
@Configurationclasses to define default beans. You should use external properties as much as possible to allow customization and try to use auto-configuration helper annotations like@AutoConfigureBefore,@AutoConfigureAfter,@ConditionalOnBean,@ConditionalOnMissingBeanetc. You can find more detailed information on each annotation in the official documentation Condition annotations - Place an auto-configuration file/files that aggregates all of the
@Configurationclasses. - Create a file named
spring.factoriesand place it insrc/main/resources/META-INF. - In
spring.factories, setorg.springframework.boot.autoconfigure.EnableAutoConfigurationproperty with comma separated values of your@Configurationclasses:
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.mycorp.libx.autoconfigure.LibXAutoConfiguration,\
com.mycorp.libx.autoconfigure.LibXWebAutoConfiguration
Using this method you can create your own auto-configuration classes that will be picked by spring-boot. Spring-boot automatically scan all maven/gradle dependencies for a spring.factories file, if it finds one, it adds all @Configuration classes specified in it to its auto-configuration process.
Make sure your auto-configuration starter project does not contain spring boot maven plugin because it will package the project as an executable JAR and won't be loaded by the classpath as intended - spring boot will not be able to find your spring.factories and won't load your configuration
