Annotations
Autoconfiguration is enabled by @EnableAutoConfiguration.
@SpringBootConfiguration -> extends @Configuration
@ComponentScan("..")
@EnableAutoConfiguration
public class Application {
public static void main(String[] args){
SpringApplication.run(Application.class,args);
}
}SpringBootConfiguration
Indicates that a class provides Spring Boot application @Configuration. Can be used as an alternative to the Spring’s standard @Configuration annotation so that configuration can be found automatically (for example in tests).
Application should only ever include one @SpringBootConfiguration and most idiomatic Spring Boot applications will inherit it from @SpringBootApplication. (source)
SpringBootApplication
Annotation @SpringBootApplication comprehends the following annotations:
- @EnableAutoConfiguration
- @ComponentScan
- @SpringBootConfiguration
@SpringBootApplication(scanBasePackages="..")
public class Application{
}
Tests
@SpringBootTest is an alternative to @SpringJUnitConfig.
@SpringBootTest(classes=Application.class) --> loads config from @SpringBootApplication class
public class TransferServicesTests {
@Autowired
private TransferService transferService;
@Test
public void successfulTransfer(){
TransferConfirmation conf = transferService.transfer(...);
...
}
}Properties
Spring looks for application.properties, application-{profile}.properties file, in:
- classpath
- /config folder in package or working directory
- working directory while using the jar
Property file application.yml requires snakeYaml dependency and it’s not supported by @PropertySource, the yaml file can have sections with profile definitions.
---
spring:
profiles: cloud
xxxx: xxxx@ConfigurationProperties
This annotation will hold externalized properties, avoids repeating prefix and set values from data members from corresponding properties.
application.properties
-----
rewards.client.host=192.168.1.42
rewards.client.port=8080
rewards.client.logdir=/logs
rewards.client.timeout=2000
---
@ConfigurationProperties(prefix="rewards.client")
public class ConnectionSettings {
private String host;
private int port;
private Strong logdir;
private int timeout;
}Enabling @ConfigurationProperties can be one in three ways:
In application class:
@SpringBootApplication
@EnableConfigurationProperties(ConnectionSetting.class)
public class RewardsApplication { .. }Add @ConfigurationPropertiesScan to application class:
@SpringBootApplication
@ConfigurationPropertiesScan
public class RewardsApplication {..}Add @Component the configuration bean class itself:
@Component
@ConfigurationProperties(prefix="rewards.client")
public class ConnectionSettings {..}Auto-configuration
Auto configuration is enable in @SpringBootApplication or using @EnableAutoConfiguration.
Creating a conditional clause:
//Create JdbcTemplate bean only when DataSource bean already exists
@Bean
@ConditionalOnBean(DataSource.class) // no need for @Autowired
public JdbcTemplate jdbcTemplate(DataSource dataSource){
return new Jdbc;
}
//also: @ConditionalOnMissingBean, @ConditionalOnMissingClass, @ConditionalOnClass, @ConditionalOnProperty, ...Override Auto-configuration
Ways of override Spring auto configuration:
- definitions in application.properties
- Define the proper beans (ex. DataSoruce).
- Disable autoconfiguration.
@EnableAutoConfiguration(exclude=DataSourceAutoConfiguration.class) --> also, @SpringBootApplication
public class ApplicationConfiguration {
..
}
Or use configuration
spring.autoconfigure.exclude=x.x..MyClass