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AbstractHandlerMethodMapping类详解 - HandlerMapping系列八

AbstractHandlerMethodMapping当bean被注入到容器后会执行一系列的初始化过程,用于注解@Controller,@RequestMapping来定义controller。

AbstractHandlerMethodMapping源码

//抽象方法，并实现了initializingBean接口，其实主要的注册操作则是通过afterPropertiesSet()接口方法来调用的
public abstract class AbstractHandlerMethodMappingextends AbstractHandlerMapping implements InitializingBean{}

//容器启动时会运行此方法，完成handlerMethod的注册操作  
@Override  
public void afterPropertiesSet() {  
	initHandlerMethods();  
}
//handlerMethod的注册操作  
protected void initHandlerMethods() {  
	if (logger.isDebugEnabled()) {  
		logger.debug("Looking for request mappings in application context: " + getApplicationContext());  
	}  
	//从springMVC容器中获取所有的beanName  
	String[] beanNames = (this.detectHandlerMethodsInAncestorContexts ?  
			BeanFactoryUtils.beanNamesForTypeIncludingAncestors(getApplicationContext(), Object.class) :  
			getApplicationContext().getBeanNamesForType(Object.class));  //注册从容器中获取的beanName  
	for (String name : beanNames) {  
		if (!name.startsWith(SCOPED_TARGET_NAME_PREFIX) && isHandler(getApplicationContext().getType(name))) {  
			detectHandlerMethods(name);  
		}  
	}  
	handlerMethodsInitialized(getHandlerMethods());  
}
//根据beanName进行一系列的注册，最终实现是在registerHandlerMethod
protected void detectHandlerMethods(final Object handler) {  
	//获取bean实例  
	Class handlerType =  
			(handler instanceof String ? getApplicationContext().getType((String) handler) : handler.getClass());  

	// Avoid repeated calls to getMappingForMethod which would rebuild RequestMappingInfo instances  
	final Map mappings = new IdentityHashMap();  
	final Class userType = ClassUtils.getUserClass(handlerType);  

	Setmethods = HandlerMethodSelector.selectMethods(userType, new MethodFilter() {  
		@Override  
		public boolean matches(Method method) {  
			//创建RequestMappingInfo  
			T mapping = getMappingForMethod(method, userType);  
			if (mapping != null) {  
				mappings.put(method, mapping);  
				return true;  
			}  
			else {  
				return false;  
			}  
		}  
	});  
  
	for (Method method : methods) {  
		registerHandlerMethod(handler, method, mappings.get(method));  
	}  
}
//注册beanName和method及RequestMappingInfo之间的关系，RequestMappingInfo会保存url信息  
@Deprecated  
protected void registerHandlerMethod(Object handler, Method method, T mapping) {  
	this.mappingRegistry.register(mapping, handler, method);  
}

进行HandlerMethod的注册操作，简单来说就是从springMVC的容器中获取所有的beanName，注册url和实现方法HandlerMethod的对应关系。