SpringMVC源碼解析二：請求處理過程3

第三步的處理過程：

    //3. 獲取處理request的處理器適配器handler adapter
    HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());

getHandlerAdapter方法：
	protected HandlerAdapter getHandlerAdapter(Object handler) throws ServletException {
		if (this.handlerAdapters != null) {
			for (HandlerAdapter ha : this.handlerAdapters) {
				if (logger.isTraceEnabled()) {
					logger.trace("Testing handler adapter [" + ha + "]");
				}
				if (ha.supports(handler)) {
					return ha;
				}
			}
		}
		throw new ServletException("No adapter for handler [" + handler +
				"]: The DispatcherServlet configuration needs to include a HandlerAdapter that supports this handler");
	}	

getHandlerAdapter方法中supports(handler)方法有三個實現類：HttpRequestHandlerAdapter，SimpleControllerHandlerAdapter，RequestMappingHandlerAdapter；對應不同的適配器處理方法。