6-EnableAutoConfiguration深入分析

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2023-12-01

@SpringBootApplication由以下注解组成

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan(
    excludeFilters = {@Filter(
    type = FilterType.CUSTOM,
    classes = {TypeExcludeFilter.class}
)}
)

6.1 加载其他项目下的bean

在classpath下创建目录META-INF/spring.factories
在META-INF/spring.factories指定项目外的配置类或其他模块的配置类org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.clsaa.core.bean.RunnableConfiguration
等于号后面可以加多个配置类,用逗号隔开
可在@EnableAutoConfiguration(exclude=XXX.class)进行排除

	protected List<String> getCandidateConfigurations(AnnotationMetadata metadata,
			AnnotationAttributes attributes) {
		List<String> configurations = SpringFactoriesLoader.loadFactoryNames(
				getSpringFactoriesLoaderFactoryClass(), getBeanClassLoader());
		Assert.notEmpty(configurations,
				"No auto configuration classes found in META-INF/spring.factories. If you "
						+ "are using a custom packaging, make sure that file is correct.");
		return configurations;
	}

实际上EnableAutoConfiguration使用了EnableAutoConfigurationImportSelector,前面讲到这个类返回一个字符串数组,把类名以字符串的形式返回,只要返回的类名就被导入到spring容器中管理起来