SpringBoot之@Controller和@RequestMapping的实现原理解读

@RestController
public class TestController {

    @GetMapping("/name")
    public String name(HttpServletRequest request){
        return request.toString();
    }
}

@RestController
public class PostController {

    @ApiOperation(value = "查询Bbs所有文章")
    @PostMapping(value = "/query/bbs/posts", produces = MediaType.APPLICATION_JSON_VALUE)
    public Result<PostAllResponse> queryBbsPostAll(@RequestBody PostAllSelectRequest postAllSelectRequest) {
        return postBiz.queryBbsPostAll(postAllSelectRequest);
    }

    public static void main(String[] args) {
        Method queryBbsPostAll = ClassUtils.getMethod(PostController.class, "queryBbsPostAll",PostAllSelectRequest.class);
        PostMapping annotation = AnnotationUtils.findAnnotation(queryBbsPostAll, PostMapping.class);
        ///query/bbs/posts
        System.out.println(StringUtils.arrayToCommaDelimitedString(annotation.value()));
        //application/json
        System.out.println(StringUtils.arrayToCommaDelimitedString(annotation.produces()));
        //是否包含RequestMapping: true
        System.out.println("是否包含RequestMapping: "+AnnotatedElementUtils.hasAnnotation(queryBbsPostAll,RequestMapping.class));

        RequestMapping mergedAnnotation = AnnotatedElementUtils.getMergedAnnotation(queryBbsPostAll, RequestMapping.class);
        ///query/bbs/posts
        System.out.println(StringUtils.arrayToCommaDelimitedString(mergedAnnotation.value()));
    }
}

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@RequestMapping(method = RequestMethod.POST)
public @interface PostMapping {
   ...
}

public abstract class AbstractHandlerMethodMapping<T> extends AbstractHandlerMapping implements InitializingBean {

    @Override
    public void afterPropertiesSet() {
        initHandlerMethods();
    }
    
    /**
  * Scan beans in the ApplicationContext, detect and register handler methods.
  * @see #getCandidateBeanNames()
  * @see #processCandidateBean
  * @see #handlerMethodsInitialized
  */
    protected void initHandlerMethods() {
        for (String beanName : getCandidateBeanNames()) {
            if (!beanName.startsWith(SCOPED_TARGET_NAME_PREFIX)) {
                processCandidateBean(beanName);
            }
        }
        handlerMethodsInitialized(getHandlerMethods());
    }
}

 @Override
 protected boolean isHandler(Class<?> beanType) {
  return (AnnotatedElementUtils.hasAnnotation(beanType, Controller.class) ||
    AnnotatedElementUtils.hasAnnotation(beanType, RequestMapping.class));
 }