java My servlet返回null
我编写了以下表单和servlet，希望servlet能够从表单返回文本字段的值，但它会返回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>");
}
}
# 1 楼答案
您应该使用
name属性而不是id向服务器发送参数