模式注解（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 .
模式注解是一种用于声明在应用中扮演“组件”角色的注解。如 Spring Framework 中的 @Repository 标注在任何类上 ，用
于扮演仓储角色的模式注解。@Component 作为一种由 Spring 容器托管的通用模式组件，任何被 @Component 标准的组件均为组件扫描的候选对象。类似地，凡是被 @Component 元标注（meta-annotated）的注解，如 @Service ，当任何组件标注它时，也被视作组件扫描的候选对象。
模式注解举例
Spring Framework 注解 场景说明 起始版本
@Repository 数据仓储模式注解 2.0
@Component 通用组件模式注解 2.5
@Service 服务模式注解 2.5
@Controller Web 控制器模式注解 2.5
@Configuration 配置类模式注解 3.0
Spring @Enable 模块装配
Spring Framework 3.1 开始支持”@Enable 模块驱动“。所谓“模块”是指具备相同领域的功能组件集合， 组合所形成一个独立
的单元。比如 Web MVC 模块、Aspect J代理模块、Caching（缓存）模块、JMX（Java 管 理扩展）模块、Async（异步处
理）模块等。
@Enable 注解模块举例
框架实现 @Enable 注解模块 激活模块
Spring Framework @Enable Web Mvc Web MVC 模块
@Enable Transaction Management 事务管理模块
@Enable Caching Caching 模块
@Enable MBean Export JMX 模块
@Enable Async 异步处理模块
Enable Web Flux Web Flux 模块
@Enable Aspect JAuto Proxy Aspect J 代理模块
Spring Boot @Enable Auto Configuration 自动装配模块
@Enable Management Context Actuator 管理模块
@Enable Configuration Properties 配置属性绑定模块
@Enable OAuth2Sso OAuth2 单点登录模块
Spring Cloud @Enable Eureka Server Eureka服务器模块
@Enable Config Server 配置服务器模块
@Enable Feign Clients Feign客户端模块
@Enable Zuul Proxy 服务网关 Zuul 模块
@Enable Circuit Breaker 服务熔断模块
实现方式
注解驱动方式
@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 {
...
}
接口编程方式
@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;
}
}