springboot如何實現自動裝配原始碼解讀
阿新 • • 發佈:2020-12-10
Spring Boot 自動裝配
最重要的註解@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
是實現自動裝配的核心註解
@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( // 載入配置元資料 getAutoConfigurationMetadata(),annotationMetadata); this.autoConfigurationEntries.add(autoConfigurationEntry); for (String importClassName : autoConfigurationEntry.getConfigurations()) { this.entries.putIfAbsent(importClassName,annotationMetadata); } } private AutoConfigurationMetadata getAutoConfigurationMetadata() { if (this.autoConfigurationMetadata == null) { // 載入配置資訊 this.autoConfigurationMetadata = AutoConfigurationMetadataLoader.loadMetadata(this.beanClassLoader); } return this.autoConfigurationMetadata; } static AutoConfigurationMetadata loadMetadata(ClassLoader classLoader,String path) { try { // 獲取資源路徑 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: 這個檔案在target編譯後的資料夾中
自動裝配
spring-boot-project/spring-boot-autoconfigure/src/main/resources/META-INF/spring.factories
該檔案記憶體有:
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:[email protected]: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; }
希望通過本篇對於springboot自動裝配的解讀,讓大家對springboot底層有了一個大致瞭解,只分析了主要方法,希望對大家有幫助
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