SpringBoot 基于注解的 AOP

google 搜索 spring aop annotation，看了一大堆，好多过时的内容，要么就特别复杂，再搜中文的 “spring 注解 代理”，看了半天也没啥帮助，今天试着试着突然搞定了，特别简单

springboot 用不着配置文件

定义注解

@Target(ElementType.METHOD)  
@Retention(RetentionPolicy.RUNTIME)  
public @interface MapCache {  
}

配置后置处理器

@Configuration  
public class AopConfig implements BeanPostProcessor {  
  
    @Override  
  public Object postProcessBeforeInitialization(Object bean, String s) throws BeansException {  
        return bean;  
    }  
  
    @Override  
  public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {  
        //这个地方不添加过滤会导致 tomcat 启动失败，目前还没定位到确切原因
        if (!bean.getClass().getName().startsWith("com.example.wsdemo")) {  
            return bean;  
        }  
        ProxyFactory factory = new ProxyFactory();  
        factory.setTarget(bean);  
        factory.addAdvisor(new MapCacheAdvice());  
  
        return factory.getProxy();  
    }  
  
}

MapCacheAdvice 源码

public class MapCacheAdvice extends DefaultPointcutAdvisor {  
    @Override  
  public Pointcut getPointcut() {  
        return new AnnotationMatchingPointcut(null, MapCache.class);  
    }  
  
    @Override  
  public Advice getAdvice() {  
        return new MapCacheInterceptor();  
    }  
  
    public static class MapCacheInterceptor implements MethodInterceptor, Advice {  
        @Override  
  public Object invoke(MethodInvocation invocation) throws Throwable {  
            System.out.println("===========================");  
            Object result = invocation.proceed();  
            System.out.println("---------------------------");  
            return result;  
        }  
    }  
}

测试

@Service  
public class SayService {  
  
    @Autowired  
    BBService bbService;  
  
    public String say() {  
        System.out.println("+++ say +++");  
        return bbService.getValue() + " hello";  
    }  
  
    @MapCache  
    public String say(String name) {  
        System.out.println("+++ say hello +++");  
        return bbService.getValue() + " hello " \+ name;  
    }  
}

@Controller  
public class IndexController {  
  
    @ResponseBody  
    @GetMapping("/test")  
    public String say() {  
        sayService.say("pk");  
        return sayService.say();  
    }  
}

调用结果

===========================
+++ say hello +++
---------------------------
+++ say +++