spring aop 在 spring 事件应用

核心 API - org.springframework.context.event.EventPublicationInterceptor
特性描述

当 Spring AOP 代理 Bean 中的 JoinPoint 方法执行之后，Spring ApplicationContext 将发布一个自定义事件（ApplicationEvent 子类）
使用限制
- EventPublicationInterceptor 关联的 ApplicationEvent 子类必须存在参数的构造器
- EventPublicationInterceptor 需要被声明为 Spring Bean

实例代码

执行事件类

public class ExecutedEvent extends ApplicationEvent {
  
    /**
     * Create a new {@code ApplicationEvent}.
     *
     * @param source the object on which the event initially occurred or with
     *               which the event is associated (never {@code null})
     */
    public ExecutedEvent(Object source) {
        super(source);
    }
}

执行器

public class Executor { // ClassFilter
  
    public void execute() { // MethodMatcher: Join Point 方法（需要 Pointcut 来匹配）
        System.out.println("Executing...");
    }
}

静态执行器 - 传统示例

public class StaticExecutor implements ApplicationEventPublisherAware {
  
    private ApplicationEventPublisher applicationEventPublisher;
  
    public void execute() {
        System.out.println("Executing...");
        applicationEventPublisher.publishEvent(new ExecutedEvent(this));
    }
  
    @Override
    public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
        this.applicationEventPublisher = applicationEventPublisher;
    }
}

EventPublicationInterceptor 示例

@Configuration // Configuration Class
@EnableAspectJAutoProxy
public class EventPublicationInterceptorDemo {
  
    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
        context.register(EventPublicationInterceptorDemo.class, Executor.class, StaticExecutor.class);
        // 启动 Spring 应用上下文
        context.refresh();
  
        // 5. 执行目标方法
        Executor executor = context.getBean(Executor.class);
  
        StaticExecutor staticExecutor = context.getBean(StaticExecutor.class);
  
        executor.execute();
  
        staticExecutor.execute();
  
        // 关闭 Spring 应用上下文
        context.close();
    }
  
    // 1. 将 EventPublicationInterceptor 声明为 Spring Bean
    @Bean
    public static EventPublicationInterceptor eventPublicationInterceptor() {
        EventPublicationInterceptor eventPublicationInterceptor = new EventPublicationInterceptor();
        // 关联目标（自定义）事件类型 - ExecutedEvent
        eventPublicationInterceptor.setApplicationEventClass(ExecutedEvent.class);
        return eventPublicationInterceptor;
    }
  
    // 2. 实现 Pointcut Bean
    @Bean
    public static Pointcut pointcut() {
        return new StaticMethodMatcherPointcut() {
            @Override
            public boolean matches(Method method, Class<?> targetClass) {
                return "execute".equals(method.getName()) && Executor.class.equals(targetClass);
            }
        };
    }
  
    // 3. 声明一个 Advisor Bean
    @Bean
    public static PointcutAdvisor pointcutAdvisor(Pointcut pointcut, EventPublicationInterceptor eventPublicationInterceptor) {
        // EventPublicationInterceptor is MethodInterceptor is Advice
        return new DefaultPointcutAdvisor(pointcut, eventPublicationInterceptor);
    }
  
    // 4. 处理事件 - ExecutedEvent
    @EventListener(ExecutedEvent.class)
    public void executed(ExecutedEvent event) {
        System.out.println("Executed : " + event);
    }
}

Spring aop 在 spring 事件应用

spring aop 在 spring 事件应用

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