ConfigurationProperties does not take effect due to lack of ConfigurationPropertiesBindingPostProcessor

Question

In my Spring Boot project, I have used Maven multi-module to organize the project structure. I have placed the database configuration in the common-db module and designed a DataBaseProperties class to add new functionality to the default database configuration in Spring Boot.

@Configuration  
@ConfigurationProperties("spring.datasource")  
@Getter  
@Setter  
@ToString  
@FieldDefaults(level = AccessLevel.PRIVATE)  
@Slf4j  
public class DataBaseProperties implements InitializingBean {  
  
    String driverClassName = "com.mysql.cj.jdbc.Driver";  
  
    Integer initialSize;  
    Integer maxActive;  
    Integer minIdle;  
    Integer maxWait;  
  
    Boolean showSql = false;  
    String basePackage = "com.example.**.mapper";  
    String[] mapperLocations;  
    Boolean cacheEnabled = true;  
  
    @Override  
    public void afterPropertiesSet() {  
        log.info("configuration properties: {}", this);  
    }  
}

In the common-db module, I use spring.factories to inject the Bean:

# Auto Configure  
org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.example.common.db.config.properties.DataBaseProperties

Then I import this common-db module into the main project. However, I found that DataBaseProperties cannot retrieve the configuration information.

I tried modifying the configuration prefix to example.datasource, but it didn't work. I also tried using @EnableConfigurationProperties to inject ConfigurationProperties, but the problem remained unresolved, and I'm not sure if it's due to incorrect usage or other reasons.

I also attempted to add the following Maven dependency, but it had no effect.

<dependency>  
    <groupId>org.springframework.boot</groupId>  
    <artifactId>spring-boot-configuration-processor</artifactId>  
</dependency>

After debugging, I found that during the initialization of DataBaseProperties, the BeanFactory is missing ConfigurationPropertiesBindingPostProcessor, which prevents it from obtaining the configuration information. However, I have written other @ConfigurationProperties classes that can retrieve the configuration information and have ConfigurationPropertiesBindingPostProcessor during initialization.

By observing the List<BeanPostProcessor> beanPostProcessors field in AbstractBeanFactory, I found that DataBaseProperties is using AnnotationConfigServletWebServerApplicationContext, while other ConfigurationProperties classes that can retrieve the configuration information use AnnotationConfigApplicationContext. There may be other ApplicationContext being used, but what I can confirm is that AnnotationConfigServletWebServerApplicationContext lacks ConfigurationProperties.

Now, I'm not sure why this PostProcessor is missing. Maybe it has always been missing? I hope someone can help me make the ConfigurationProperties class in my common-db module retrieve the configuration. I appreciate any help and thank you for reading this.