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springboot如何实现自动装配源码解读

分类:Java · 发布时间:2021-10-08 02:05 · 阅读:7668

这篇文章主要介绍了springboot如何实现自动装配源码赏析,本文通过实例代码给大家介绍的非常详细,对大家的学习或工作具有一定的参考借鉴价值,需要的朋友可以参考下

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()

 @Override public 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 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

标签:
springboot 自动装配

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