Spring Boot 自动装配

最重要的注解@SpringBootApplication

@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 { @AliasFor(annotation = EnableAutoConfiguration.class) Class<?>[] exclude() default {}; @AliasFor(annotation = EnableAutoConfiguration.class) String[] excludeName() default {}; @AliasFor(annotation = ComponentScan.class, attribute = "basePackages") String[] scanBasePackages() default {}; @AliasFor(annotation = ComponentScan.class, attribute = "basePackageClasses") Class<?>[] scanBasePackageClasses() default {}; @AliasFor(annotation = Configuration.class) boolean proxyBeanMethods() default true;}

EnableAutoConfiguration

是实现自动装配的核心注解

@Target(ElementType.TYPE)@Retention(RetentionPolicy.RUNTIME)@Documented@Inherited@AutoConfigurationPackage@Import(AutoConfigurationImportSelector.class)public @interface EnableAutoConfiguration { }

getAutoConfigurationMetadata()

@Overridepublic void process(AnnotationMetadata annotationMetadata, DeferredImportSelector deferredImportSelector) { Assert.state(deferredImportSelector instanceof AutoConfigurationImportSelector, () -> String.format("Only %s implementations are supported, got %s", AutoConfigurationImportSelector.class.getSimpleName(), deferredImportSelector.getClass().getName())); AutoConfigurationEntry autoConfigurationEntry = ((AutoConfigurationImportSelector) deferredImportSelector) .getAutoConfigurationEntry( // 加载配置元数据 getAutoConfigurationMetadata(), annotationMetadata); this.autoConfigurationEntries.add(autoConfigurationEntry); for (String importClassName : autoConfigurationEntry.getConfigurations()) { this.entries.putIfAbsent(importClassName, annotationMetadata); }}private AutoConfigurationMetadata getAutoConfigurationMetadata() { if (this.autoConfigurationMetadata == null) { // 加载配置信息 this.autoConfigurationMetadata = AutoConfigurationMetadataLoader.loadMetadata(this.beanClassLoader); } return this.autoConfigurationMetadata;}static AutoConfigurationMetadata loadMetadata(ClassLoader classLoader, String path) { try { // 获取资源路径 Enumeration<URL> urls = (classLoader != null) ? classLoader.getResources(path) : ClassLoader.getSystemResources(path); Properties properties = new Properties(); while (urls.hasMoreElements()) { properties.putAll(PropertiesLoaderUtils.loadProperties(new UrlResource(urls.nextElement()))); } return loadMetadata(properties); } catch (IOException ex) { throw new IllegalArgumentException("Unable to load @ConditionalOnClass location [" + path + "]", ex); }}protected static final String PATH = "META-INF/spring-autoconfigure-metadata.properties";

注意： 这个文件在target编译后的文件夹中
自动装配

spring-boot-project/spring-boot-autoconfigure/src/main/resources/META-INF/spring.factories

该文件内存有:

Auto Configure

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration,\org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration,\org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,\

EnableConfigurationProperties

@ConfigurationProperties(prefix = "spring.redis")public class RedisProperties { /** * Database index used by the connection factory. */ private int database = 0; /** * Connection URL. Overrides host, port, and password. User is ignored. Example: * redis://user:password@example.com:6379 */ private String url; /** * Redis server host. */ private String host = "localhost"; /** * Login password of the redis server. */ private String password; /** * Redis server port. */ private int port = 6379; /** * Whether to enable SSL support. */ private boolean ssl; /** * Connection timeout. */ private Duration timeout; /** * Client name to be set on connections with CLIENT SETNAME. */ private String clientName; }

希望通过本篇对于springboot自动装配的解读，让大家对springboot底层有了一个大致了解，只分析了主要方法，希望对大家有帮助

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