[annotation] customize annotation

[Alice52]

• Alice52/spring-5.2.x#24

type

1. method annotation
2. handler annotation
   • HandlerInterceptorAdapter
3. customize annotation
   • [@Mobile]: @Constraint(validatedBy = MobileDescriptor.class)
   • [@Email]: EmailValidator: 创建 validator是会内置
   • validator: ConstraintValidator
   • [@Transactional]: aop 上做拦截: 可以使用 @Around 注解做拦截 || MethodInterceptor + DefaultPointcutAdvisor + AnnotationMatchingPointcut
     • 可以自定义延迟消费注解: @RocketMQBasedDelay
     • @LocalIdempotentRequest
     • @LocalLimitRequest
     • [@DeSensitive]: 数据脱敏, 序列化相关
     • [@DateTimeFormat]: 屏蔽底层细节-运行时参数类型获取对应的 Parser/Printer 进行工作

4. spring annotation

   • 使用AOP切面做拦截指定注解: 注解 + 切面
   • 使用APC获取被指定注解修饰的类: ListableBeanFactory.findAnnotationOnBean(String beanName, Class<A> annotationType)
   • 使用spring的工具类: AnnotationUtils.findAnnotation(Class<?> clazz, Class<A> annotationType)

   • 使用DLBF获取被指定注解修饰的类: AnnotationUtils.getAnnotation(Method method, Class<A> annotationType)

     public static <A extends Annotation> A findAnnotationOnBean(
           String beanName, Class<A> annotationType) {
       AbstractApplicationContext context =
               (AbstractApplicationContext) ApplicationContextHolder.getInstance();
       ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
     
       return Optional.of(beanFactory)
               .map(each -> (RootBeanDefinition) beanFactory.getMergedBeanDefinition(beanName))
               .map(RootBeanDefinition::getResolvedFactoryMethod)
               .map(factoryMethod -> AnnotationUtils.getAnnotation(factoryMethod, annotationType))
               .orElse(null);
     }

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issue list

3. how to define?

   @ParamsValidate(value = {@ParamValidate(name = "name", notNull = true, message = "不能为空", maxLen = 200)})

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reference

1. https://www.cnblogs.com/peida/archive/2013/04/24/3036689.html

[Alice52]

annotation member type limit: got from oracle 官方的 docs

1. A primitive type
2. String
3. Class
4. An enum type
5. An annotation type
6. An array type ：类型为以上任一类型的数组