Servlet doPost 失败！

小白 仿照网上代码编写
RequestContext req = new ServletRequestContext(request);
执行 第一句就卡住 不能继续进行了。麻烦各路大神指教一下。

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    PrintWriter pw = response.getWriter(); 
    pw.println("doPost");
      RequestContext req = new ServletRequestContext(request);  
      pw.println("doPost111");

你可以先在doGet()方法中测试一下，doPost一般是用在表单中