Question

我编写了以下表单和servlet，希望servlet从表单中返回文本字段的值，但它返回 null 。应该纠正什么？

<html>
<head>
<title>Simple form</title>
</head>
<body>
    <form method="post" action="theServlet">
    <input type="text" id="userName"/>
    <input type="submit" value="Post"/>
</form>
</body>
</html>



  public class theServlet extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        String username=request.getParameter("userName");

        response.setContentType("text/html");       
        PrintWriter writer=response.getWriter();
        writer.println("<html>");
        writer.println("userName = "+ username);    
        writer.println("</html>");

    } 
}

Answer 1

您应该使用name属性而不是id将参数发送到服务器。

<input type="text" id="userName" name="username" />

我的servlet返回null

1 个答案: