if(mappedHandler.getHandler() instanceof MultiActionController){ 
  ((MultiActionController)mappedHandler.getHandler()).xxx 
}else if(mappedHandler.getHandler() instanceof XXX){ 
  ... 
}else if(...){ 
  ... 
}

//定义一个Adapter接口 
public interface HandlerAdapter {
 public Boolean supports(Object handler);
 public void handle(Object handler);
}
//以下是三种Controller实现 
public interface Controller {
}
public class HttpController implements Controller{
 public void doHttpHandler(){
  System.out.println("http...");
 }
}
public class SimpleController implements Controller{
 public void doSimplerHandler(){
  System.out.println("simple...");
 }
}
public class AnnotationController implements Controller{
 public void doAnnotationHandler(){
  System.out.println("annotation...");
 }
}
//下面编写适配器类 
public class SimpleHandlerAdapter implements HandlerAdapter {
 public void handle(Object handler) {
  ((SimpleController)handler).doSimplerHandler();
 }
 public Boolean supports(Object handler) {
  return (handler instanceof SimpleController);
 }
}
public class HttpHandlerAdapter implements HandlerAdapter {
 public void handle(Object handler) {
  ((HttpController)handler).doHttpHandler();
 }
 public Boolean supports(Object handler) {
  return (handler instanceof HttpController);
 }
}
public class AnnotationHandlerAdapter implements HandlerAdapter {
 public void handle(Object handler) {
  ((AnnotationController)handler).doAnnotationHandler();
 }
 public Boolean supports(Object handler) {
  return (handler instanceof AnnotationController);
 }
}
//模拟一个DispatcherServlet 
import java.util.ArrayList;
import java.util.List;
public class DispatchServlet {
 public static List<HandlerAdapter> handlerAdapters = new ArrayList<HandlerAdapter>();
 public DispatchServlet(){
  handlerAdapters.add(new AnnotationHandlerAdapter());
  handlerAdapters.add(new HttpHandlerAdapter());
  handlerAdapters.add(new SimpleHandlerAdapter());
 }
 public void doDispatch(){
  //此处模拟SpringMVC从request取handler的对象，仅仅new出，可以出，        
  //不论实现何种Controller，适配器总能经过适配以后得到想要的结果 
  //   HttpController controller = new HttpController(); 
  //   AnnotationController controller = new AnnotationController(); 
  SimpleController controller = new SimpleController();
  //得到对应适配器 
  HandlerAdapter adapter = getHandler(controller);
  //通过适配器执行对应的controller对应方法 
  adapter.handle(controller);
 }
 public HandlerAdapter getHandler(Controller controller){
  for (HandlerAdapter adapter: this.handlerAdapters){
   if(adapter.supports(controller)){
    return adapter;
   }
  }
  return null;
 }
 public static void main(String[] args){
  new DispatchServlet().doDispatch();
 }
}