Spring Boot auto-configuration attempts to automatically configure your Spring
application based on the jar dependencies that you have added. For example, If
HSQLDB is on your classpath, and you have not manually configured any database
connection beans, then we will auto-configure an in-memory database.
You need to opt-in to auto-configuration by adding the @EnableAutoConfiguration or
@SpringBootApplication annotations to one of your @Configuration classes.
![[Tip]](images/tip.png) | Tip |
|---|---|
You should only ever add one |
Auto-configuration is noninvasive, at any point you can start to define your own
configuration to replace specific parts of the auto-configuration. For example, if
you add your own DataSource bean, the default embedded database support will back away.
If you need to find out what auto-configuration is currently being applied, and why,
start your application with the --debug switch. This will enable debug logs for a
selection of core loggers and log an auto-configuration report to the console.
If you find that specific auto-configure classes are being applied that you don’t want,
you can use the exclude attribute of @EnableAutoConfiguration to disable them.
import org.springframework.boot.autoconfigure.*; import org.springframework.boot.autoconfigure.jdbc.*; import org.springframework.context.annotation.*; @Configuration @EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class}) public class MyConfiguration { }
If the class is not on the classpath, you can use the excludeName attribute of
the annotation and specify the fully qualified name instead. Finally, you can also
control the list of auto-configuration classes to exclude via the
spring.autoconfigure.exclude property.
| Tip |
|---|---|
You can define exclusions both at the annotation level and using the property. |