spring獲取controller方法中自定義註解的信息

序

本文主要聊一下如何在spring容器啓動時，獲取有自定義註解的方法信息。

RequestMappingHandlerMapping

spring-webmvc-4.3.10.RELEASE-sources.jar!/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMapping.java

public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMapping
        implements MatchableHandlerMapping, EmbeddedValueResolverAware {

    private boolean useSuffixPatternMatch = true;

    private boolean useRegisteredSuffixPatternMatch = false;

    private boolean useTrailingSlashMatch = true;

    private ContentNegotiationManager contentNegotiationManager = new ContentNegotiationManager();

    private StringValueResolver embeddedValueResolver;

    private RequestMappingInfo.BuilderConfiguration config = new RequestMappingInfo.BuilderConfiguration();
    
    //....
}

• getHandlerMethods
  spring-webmvc-4.3.10.RELEASE-sources.jar!/org/springframework/web/servlet/handler/AbstractHandlerMethodMapping.java

/**
     * Return a (read-only) map with all mappings and HandlerMethod's.
     */
    public Map<T, HandlerMethod> getHandlerMethods() {
        this.mappingRegistry.acquireReadLock();
        try {
            return Collections.unmodifiableMap(this.mappingRegistry.getMappings());
        }
        finally {
            this.mappingRegistry.releaseReadLock();
        }
    }

主要用到這個getHandlerMethods方法

Map<RequestMappingInfo,HandlerMethod>

for(Map.Entry<RequestMappingInfo,HandlerMethod> entry : urlMethodMapping.entrySet()){

            RequestMappingInfo info = entry.getKey();
            HandlerMethod handlerMethod = entry.getValue();
            Method method = handlerMethod.getMethod();

            if(!method.isAnnotationPresent(DemoAnno.class)){
                continue;
            }

            DemoAnno demoAnno = method.getAnnotation(DemoAnno.class);
            //......
        }

經過這個HandlerMethod就能夠獲取具體的請求的方法，而後利用反射去判斷是否有標註本身所須要的註解。

啓動時處理

實現ApplicationListener<ContextRefreshedEvent>接口，在

@Override
    public void onApplicationEvent(ContextRefreshedEvent contextRefreshedEvent) {
        //.......
    }

在onApplicationEvent中去處理
這樣就大功告成了