Spring MVC之HandlerMap 初始化(RequestmappingHandlerMapping)

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    AbstractHandlerMethodMapping类实现了InitializingBean接口，在属性初始化完成后会调用afterPropertiesSet()方法，在该方法中调用initHandlerMethods();进行HandlerMethod初始化。

   

/**
	 * 扫描ApplicationContext中的Bean，查找并注册 handlerMethod
	 */
	protected void initHandlerMethods() {
		if (logger.isDebugEnabled()) {
			logger.debug("Looking for request mappings in application context: " + getApplicationContext());
		}
		//从ApplicationContext中获取所有Bean名称
		String[] beanNames = (this.detectHandlerMethodsInAncestorContexts ?
				BeanFactoryUtils.beanNamesForTypeIncludingAncestors(getApplicationContext(), Object.class) :
				getApplicationContext().getBeanNamesForType(Object.class));
		//遍历Bean
		for (String name : beanNames) {
			if (!name.startsWith(SCOPED_TARGET_NAME_PREFIX) && isHandler(getApplicationContext().getType(name))) {
				//从bean中查找handler method
				detectHandlerMethods(name);
			}
		}
		//handler method 初始化
		handlerMethodsInitialized(getHandlerMethods());
	}

 

/**
	 * 从一个Handler中查找 handler method
	 */
	protected void detectHandlerMethods(final Object handler) {
		Class handlerType =
				(handler instanceof String ? getApplicationContext().getType((String) handler) : handler.getClass());

		
		final Map mappings = new IdentityHashMap();
		//获取Class
		final Class userType = ClassUtils.getUserClass(handlerType);

		Set methods = HandlerMethodSelector.selectMethods(userType, new MethodFilter() {
			@Override
			public boolean matches(Method method) {
				T mapping = getMappingForMethod(method, userType);
				if (mapping != null) {
					mappings.put(method, mapping);
					return true;
				}
				else {
					return false;
				}
			}
		});
		//遍历所有handler method，并注册
		for (Method method : methods) {
			registerHandlerMethod(handler, method, mappings.get(method));
		}
	}

 isHandler 在RequestMappingHandlerMapping 具体实现

	/**
	 * {@inheritDoc}
	 * Expects a handler to have a type-level @{@link Controller} annotation.
	 */
	@Override
	protected boolean isHandler(Class beanType) {
		return ((AnnotationUtils.findAnnotation(beanType, Controller.class) != null) ||
				(AnnotationUtils.findAnnotation(beanType, RequestMapping.class) != null));
	}