2.6完善反射的代码

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

        // 假设url是： http://localhost:8080/mymvc/hello.do
        // ServletPath是Servlet的访问路径： /hello.do
        // 思路是：
        // 第1步： /hello.do -> hello
        // 第2步： hello -> HelloController
        String servletPath = request.getServletPath(); // /hello.do
        int lastDotIndex = servletPath.lastIndexOf(".do");
        servletPath = servletPath.substring(1, lastDotIndex); // hello

        // 通过ServletPath获取对应的Controller对象
        Object xxxController = map.get(servletPath);

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

        try {
            // 这里只能try...catch异常，因为在重写的方法里，不能抛出比父类更大的异常
            Method method = xxxController.getClass().getDeclaredMethod(ac, HttpServletRequest.class,
                    HttpServletResponse.class);
            if (method != null) {
                method.invoke(xxxController, request, response);
            } else {
                throw new RuntimeException("ac值错误");
            }
        } catch (NoSuchMethodException | SecurityException | IllegalAccessException | IllegalArgumentException
                | InvocationTargetException e) {
            e.printStackTrace();
        }
    }