org.springframework.web.servlet.DispatcherServlet-doDispatch-getHandlerAdapter

org.springframework.web.servlet.DispatcherServlet#doDispatch中

	/**
				 * 3.根據mappedHandler  HandlerExecutionChain  HandlerAdapter適配器
				 */
				// Determine handler adapter for the current request.
				HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());

getHandlerAdapter方法

	protected HandlerAdapter getHandlerAdapter(Object handler) throws ServletException {
		if (this.handlerAdapters != null) {
			for (HandlerAdapter adapter : this.handlerAdapters) {
			/**
			循環判斷哪個
			*/
				if (adapter.supports(handler)) {
					return adapter;
				}
			}
		}

HttpRequestHandlerAdapter

如果實現了HttpRequestHandler就走這個

public class HttpRequestHandlerAdapter implements HandlerAdapter {

	@Override
	public boolean supports(Object handler) {
	//判斷 下類型
		return (handler instanceof HttpRequestHandler);
	}

SimpleControllerHandlerAdapter

如果是實現了Controller接口就走這個

public class SimpleControllerHandlerAdapter implements HandlerAdapter {

	@Override
	public boolean supports(Object handler) {
		return (handler instanceof Controller);
	}

RequestMappingHandlerAdapter

public final boolean supports(Object handler) {
		return (handler instanceof HandlerMethod && supportsInternal((HandlerMethod) handler));
	}