function test(){
    $.getJSON("JsonServlet",function(result){
      alert(result.name);
    });
  }

@Override
  protected void doPost(HttpServletRequest req, HttpServletResponse resp)
      throws ServletException, IOException {
    String person="{\"name\":\"zhangsan\",\"sex\":\"man\",\"age\":\"23\"}";
    resp.getWriter().print(person);
  }