标签：aging source file 自动配置 https interface ogg ida nim
springboot的启动注解是@SpringBootApplication，它是一个组合注解，是由@SpringBootConfiguration、@EnableAutoConfiguration、@ComponentScan组成的。而自动配置就是由@EnableAutoConfiguration所进行的。
@Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Inherited @SpringBootConfiguration @EnableAutoConfiguration @ComponentScan(excludeFilters = { @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class), @Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) }) public @interface SpringBootApplication {}
在@EnableAutoConfiguration中可以看到，它也是一个组合注解，由@Import引入了一个自动配置引入选择器。
@Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Inherited @AutoConfigurationPackage @Import(AutoConfigurationImportSelector.class) public @interface EnableAutoConfiguration {
在AutoConfigurationImportSelector中
@Override public String[] selectImports(AnnotationMetadata annotationMetadata) { if (!isEnabled(annotationMetadata)) { return NO_IMPORTS; } AutoConfigurationEntry autoConfigurationEntry = getAutoConfigurationEntry(annotationMetadata); return StringUtils.toStringArray(autoConfigurationEntry.getConfigurations()); }
这个方法就是在选择引用什么，实际的操作在getAutoConfigurationEntry()中进行的。
protected AutoConfigurationEntry getAutoConfigurationEntry(AnnotationMetadata annotationMetadata) { if (!isEnabled(annotationMetadata)) { return EMPTY_ENTRY; } AnnotationAttributes attributes = getAttributes(annotationMetadata); List<String> configurations = getCandidateConfigurations(annotationMetadata, attributes); configurations = removeDuplicates(configurations); Set<String> exclusions = getExclusions(annotationMetadata, attributes); checkExcludedClasses(configurations, exclusions); configurations.removeAll(exclusions); configurations = getConfigurationClassFilter().filter(configurations); fireAutoConfigurationImportEvents(configurations, exclusions); return new AutoConfigurationEntry(configurations, exclusions); }
getCandidateConfigurations查看这个方法可以看到它调用了SpringFactoriesLoade方法。
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; }
public final class SpringFactoriesLoader { public static final java.lang.String FACTORIES_RESOURCE_LOCATION = "META-INF/spring.factories"; private static final org.apache.commons.logging.Log logger; static final java.util.Map<java.lang.ClassLoader,java.util.Map<java.lang.String,java.util.List<java.lang.String>>> cache; }
在这里可以清晰的看到META-INF/spring.factories这个路径。
总结
Spring Boot启动的时候会通过@EnableAutoConfiguration注解找到META-INF/spring.factories配置文件中的所有自动配置类，并对其进行加载，而这些自动配置类都是以AutoConfiguration结尾来命名的，它实际上就是一个JavaConfig形式的Spring容器配置类，它能通过以Properties结尾命名的类中取得在全局配置文件中配置的属性如：server.port，而XxxxProperties类是通过@ConfigurationProperties注解与全局配置文件中对应的属性进行绑定的。
https://blog.csdn.net/u014745069/article/details/83820511
标签：aging source file 自动配置 https interface ogg ida nim
原文地址：https://www.cnblogs.com/sc19/p/14406553.html
