@Override
    protected void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // 設定編碼
        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");
        response.setContentType("text/html;charset=UTF-8
 
");

        // 假設url是： http://localhost:8080/mymvc2/hello.do
        // ServletPath是Servlet的訪問路徑： /hello.do
        // 思路是：
        // 第1步： /hello.do -> hello 或者 /book.do -> book
        // 第2步： hello -> HelloController 或者 book -> BookController
        String servletPath = request.getServletPath(); // /hello.do
 

        int lastDotIndex = servletPath.lastIndexOf(".do");
        servletPath = servletPath.substring(1, lastDotIndex); // hello

        //通過ServletPath獲取對應的Controller物件
        Object xxxController = map.get(servletPath);

        String ac = request.getParameter("ac");
        System.out.println("=======
 
" + ac + "======");
        if (StringUtil.isEmpty(ac))
            ac = "index";

        // 獲取當前類的所有方法
        Method[] methods = xxxController.getClass().getDeclaredMethods();

        for (Method m : methods) {
            // 獲取方法名稱
            String methodName = m.getName();
            if (ac.equals(methodName)) {
                // 找到和ac同名的方法，那麼通過反射技術呼叫它
                try {
                    m.invoke(this, request, response);
                    return;
                } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
                    e.printStackTrace();
                }
            }
        }

        throw new RuntimeException("ac值違法");
    }