源码分析pom.xml第三方依赖如何自动配置导入Bean容器SpringFactoriesLoader-spring.factories

• pom.xml中导入的第三方jar包依赖是如何实现自动注入bean容器的？
  另一篇文章中提到入口类的@SpringBootApplication注解整合了@EnableAutoConfiguration注解。
  @EnableAutoConfiguration注解源码如下：

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@AutoConfigurationPackage
@Import(AutoConfigurationImportSelector.class)
public @interface EnableAutoConfiguration {
   String ENABLED_OVERRIDE_PROPERTY = "spring.boot.enableautoconfiguration";
  
   Class<?>[] exclude() default {};
   String[] excludeName() default {};
}

@EnableAutoConfiguration注解通过@Import导入的处理类是AutoConfigurationImportSelector，AutoConfigurationImportSelector源码如下：

public class AutoConfigurationImportSelector implements DeferredImportSelector, BeanClassLoaderAware,
		ResourceLoaderAware, beanfactoryAware, EnvironmentAware, Ordered {

	private static final AutoConfigurationEntry EMPTY_ENTRY = new AutoConfigurationEntry();

	private static final String[] NO_IMPORTS = {};

	private static final Log logger = LogFactory.getLog(AutoConfigurationImportSelector.class);

	private static final String PROPERTY_NAME_AUTOCONfigURE_EXCLUDE = "spring.autoconfigure.exclude";

	private ConfigurableListablebeanfactory beanfactory;

	private Environment environment;

	private ClassLoader beanClassLoader;

	private ResourceLoader resourceLoader;

	private ConfigurationClassFilter configurationClassFilter;

	@Override
	public String[] selectImports(AnnotationMetadata annotationMetadata) {
		if (!isEnabled(annotationMetadata)) {
			return NO_IMPORTS;
		}
		AutoConfigurationEntry autoConfigurationEntry = getAutoConfigurationEntry(annotationMetadata);
		return StringUtils.toStringArray(autoConfigurationEntry.getConfigurations());
	}

通过selectImports()方法追踪getAutoConfigurationEntry()，源码如下：

configurations作为AutoConfigurationEntry的构造参数返回，追踪对configurations的赋值getCandidateConfigurations()方法，源码如下：

通过SpringFactoriesLoader获得configurations并返回，追踪SpringFactoriesLoader源码：

扫描所有jar包类路径下 Meta‐INF下的spring.factories文件，将EnableAutoConfiguration的值加入到bean容器中，每一个XxxAutoConfiguration类都是一个组件，就实现了自动配置。
例如对于MyBatis的整合，就是通过spring.factories文件中EnableAutoConfiguration的值MyBatisAutoConfiguration导入MyBatis的配置。