자동 구성과 Spring Boot 스타터

Spring Boot 자동 구성이란 무엇입니까

@SpringBootApplication 애너테이션

@SpringBootApplication
public class MyApp {
    public static void main(String[] args) {
        SpringApplication.run(MyApp.class, args);
    }
}

자동 구성의 작동 방식

// Spring Boot 3 imports file:
// org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration
// org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration

@ConditionalOnClass와 @ConditionalOnMissingBean

@AutoConfiguration
@ConditionalOnClass(DataSource.class)
@ConditionalOnMissingBean(DataSource.class)
public class DataSourceAutoConfiguration {
    @Bean
    public DataSource dataSource(DataSourceProperties props) {
        return DataSourceBuilder.create().build();
    }
}

Spring Boot 스타터

// build.gradle:
dependencies {
    implementation "org.springframework.boot:spring-boot-starter-web"
    implementation "org.springframework.boot:spring-boot-starter-data-jpa"
    implementation "org.springframework.boot:spring-boot-starter-validation"
}

일반적인 스타터

자동 구성 재정의

// Override auto-configured ObjectMapper:
@Configuration
public class JacksonConfig {
    @Bean
    public ObjectMapper objectMapper() {
        return new ObjectMapper()
            .disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
            .registerModule(new JavaTimeModule());
    }
}

자동 구성 제외

@SpringBootApplication(exclude = {
    DataSourceAutoConfiguration.class,
    SecurityAutoConfiguration.class
})
public class MyApp { ... }

사용자 지정 스타터 만들기

// my-starter/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports:
// com.example.MyLibraryAutoConfiguration

자동 구성 디버깅

java -jar myapp.jar --debug
# Or in application.properties:
# logging.level.org.springframework.boot.autoconfigure=DEBUG

Actuator /conditions 엔드포인트

# application.properties:
management.endpoints.web.exposure.include=conditions
# Then:
curl http://localhost:8080/actuator/conditions

확인 문제

복습