举个例子：
页面：
servlet（在doPost方法中获取，和form的method属性一致）：
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String date = request.getParameter("mdate");//获取日期文本框内容
}
