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java - 简单的 NetBeans servlet，按钮不起作用

转载 作者：行者123 更新时间：2023-12-01 18:26:57 24 4
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我从 NetBeans 开始，实现一个表单，当您按下“提交”按钮时，该表单将执行验证并告诉您输入的数据是否正确。我还没有到达验证部分，目前我想做的就是，当单击“提交”按钮时，会弹出一条消息。我在这里遇到了麻烦，我感觉这是一个快速简单的修复，但我在留言板或文档上没有找到任何内容。

编辑 - 谢谢大家!缺少“form”标签。我想这很简单，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>

这里是 ClientInformationServlet.java 文件，最重要的是 processRequest 方法，而 if (request.getParameter("validation")!= null) 行是我试图让行动发生。 

/*
 * 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>
}

最佳答案

HTML specification州

The elements used to create controls generally appear inside a FORM element, but may also appear outside of a FORM element declaration when they are used to build user interfaces. This is discussed in the section on intrinsic events. Note that controls outside a form cannot be successful controls.

A <input> element for submit is a control 。因此，如果它出现在 <form> 之外，正如您目前拥有的那样，单击它不会执行任何操作。

嵌套您的 <input> <form> 中的元素(以及任何其他显示元素)其中指定 action和method用于提交您的数据。

关于java - 简单的 NetBeans servlet，按钮不起作用，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25792225/

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