Question

我从NetBeans开始，并实施一个表单，当您按下＆＃34;提交＆＃34;按钮，执行验证并告诉您输入的数据是否正确。我还没有进入验证部分，目前我所要做的就是，当提交＆＃34;单击按钮，弹出一条消息。我在这里遇到麻烦，我觉得这是一个简单的快速修复，但我没有在留言板或文档上找到任何东西。

编辑 - 谢谢你们！错过了＃34;形式＆＃34;标签。我认为这很简单，再次感谢大家的帮助！

这是我的index.html文件：

<!DOCTYPE html>
<!--
To change this license header, choose License Headers in Project Properties.
To change this template file, choose Tools | Templates
and open the template in the editor.
-->
<html>
    <head>
        <title>Client Information</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
    </head>
    <body>
        <div><h1>Client Information</h1><table border="1">
                <tbody>
                    <tr>
                        <td>First Name</td>
                        <td><input type="text" name="FirstName" value="" size="50" /></td>
                        <td>Surname</td>
                        <td><input type="text" name="Surname" value="" size="50"/></td>
                    </tr>
                    <tr>
                        <td>Age</td>
                        <td><input type="number" name="Age" value="" min="0" max="120"/></td>
                        <td>Gender</td>
                        <td><input type="text" name="Gender" value="" size="1" maxlength="1"/></td>
                    </tr>
                </tbody>
            </table>
            <input type="submit" value="Submit" name="validation" />
        </div>
    </body>
</html>

这是ClientInformationServlet.java文件，最重要的是processRequest方法，而if (request.getParameter("validation")!= null)行是我尝试进行操作的地方。

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package clientInformation;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author nicolasdubus
 */
@WebServlet(name = "ClientInformationServlet", urlPatterns = {"/clientinformationservlet"})
public class ClientInformationServlet extends HttpServlet {

    /*
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        out.println("<html>");
        out.println("<head>");
        out.println("<title>Client Information</title>");
        out.println("</head>");
        out.println("<body>");

        String sfirst = request.getParameter("FirstName");
        String ssecond = request.getParameter("SurName");
        String sAge = request.getParameter("Age");
        String sGender = request.getParameter("Gender");
        try {
            Integer age = Integer.parseInt(sAge);
            if (request.getParameter("validation") != null) {
            System.out.println("<h1>Client information is valid</h1>");
            out.println("<h1>Client</h1>");
            System.exit(0);
            }
        } catch (IllegalArgumentException e) {
            out.println("<h1>Client information is invalid, please verify entries</h1>");
        }
        out.println("<body>");
        out.println("</html");
        /* */
        out.close();
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>
}

Answer 1

HTML specification州

用于创建控件的元素通常出现在FORM中元素，但也可能出现在FORM元素声明之外当它们用于构建用户界面时。这将在讨论中讨论关于内在事件的部分。 请注意，form外的控件不能成功控制。

A <input> element for submit is a control。因此，如果它出现在<form>之外，就像您目前所拥有的那样，点击它就不会做任何事情。

将<input>元素（以及其他任何显示元素）嵌套在<form>中，指定用于提交数据的action和method。

Answer 2

如果您想提交，那么您的html中应该有<form>

例如

<form name="input" action="/clientinformationservlet" method="POST">
      // your inputs
</form>

Answer 3

你应该添加

<body><form action="/clientinformationservlet" method="POST">

...

</form></body>

在体内。

简单的NetBeans servlet，按钮不起作用

3 个答案: