模式註解（Stereotype Annotations）
A stereotype annotation is an annotation that is used to declare the role that a component plays within the
application. For example, the @Repository annotation in the Spring Framework is a marker for any class that fulfills the role or stereotype of a repository (also known as Data Access Object or DAO).@Component is a generic stereotype for any Spring-managed component. Any component annotated with @Component is a candidate for component scanning. Similarly, any component annotated with an annotation that is itself meta-annotated with @Component is also a candidate for component scanning. For example, @Service is meta-annotated with @Component .
模式註解是一種用於聲明在應用中扮演“組件”角色的註解。如 Spring Framework 中的 @Repository 標註在任何類上 ，用
於扮演倉儲角色的模式註解。@Component 作爲一種由 Spring 容器託管的通用模式組件，任何被 @Component 標準的組件均爲組件掃描的候選對象。類似地，凡是被 @Component 元標註（meta-annotated）的註解，如 @Service ，當任何組件標註它時，也被視作組件掃描的候選對象。
模式註解舉例
Spring Framework 註解 場景說明 起始版本
@Repository 數據倉儲模式註解 2.0
@Component 通用組件模式註解 2.5
@Service 服務模式註解 2.5
@Controller Web 控制器模式註解 2.5
@Configuration 配置類模式註解 3.0
Spring @Enable 模塊裝配
Spring Framework 3.1 開始支持”@Enable 模塊驅動“。所謂“模塊”是指具備相同領域的功能組件集合， 組合所形成一個獨立
的單元。比如 Web MVC 模塊、Aspect J代理模塊、Caching（緩存）模塊、JMX（Java 管 理擴展）模塊、Async（異步處
理）模塊等。
@Enable 註解模塊舉例
框架實現 @Enable 註解模塊 激活模塊
Spring Framework @Enable Web Mvc Web MVC 模塊
@Enable Transaction Management 事務管理模塊
@Enable Caching Caching 模塊
@Enable MBean Export JMX 模塊
@Enable Async 異步處理模塊
Enable Web Flux Web Flux 模塊
@Enable Aspect JAuto Proxy Aspect J 代理模塊
Spring Boot @Enable Auto Configuration 自動裝配模塊
@Enable Management Context Actuator 管理模塊
@Enable Configuration Properties 配置屬性綁定模塊
@Enable OAuth2Sso OAuth2 單點登錄模塊
Spring Cloud @Enable Eureka Server Eureka服務器模塊
@Enable Config Server 配置服務器模塊
@Enable Feign Clients Feign客戶端模塊
@Enable Zuul Proxy 服務網關 Zuul 模塊
@Enable Circuit Breaker 服務熔斷模塊
實現方式
註解驅動方式
@Retention(Retention Policy.RUNTIME)
@Target(Element Type.TYPE)
@Documented
@Import(Delegating Web Mvc Configuration.class)
public @interface Enable Web Mvc {
}
@Configuration
public class Delegating Web Mvc Configuration extends
Web Mvc Configuration Support {
...
}
接口編程方式
@Target(Element Type.TYPE)
@Retention(Retention Policy.RUNTIME)
@Documented
@Import(Caching Configuration Selector.class)
public @interface Enable Caching {
...
}
public class Caching Configuration Selector extends Advice Mode Import Selector<Enable Caching> {
/**
* {@inherit Doc}
* @return {@link Proxy Caching Configuration} or {@code
Aspect JCache Configuration} for
* {@code PROXY} and {@code ASPECTJ} values of {@link
Enable Caching#mode()}, respectively
*/
public String[] select Imports(Advice Mode advice Mode) {
switch (advice Mode) {
case PROXY:
return new String[] {
Auto Proxy Registrar.class.get Name(),Proxy Caching Configuration.class.get Name() };
case ASPECTJ:
return new String[] {
Annotation Config Utils.CACHE_ASPECT_CONFIGURATION_CLASS_NAME };
default:
return null;
}
}