问题遇到的现象和发生背景

问题相关代码，请勿粘贴截图

运行结果及报错内容

我的解答思路和尝试过的方法

我想要达到的结果

package com.sanhuai.web;
/**

• @ Date 2022/04/21
• @ author 三槐
• @ SJY
• /

import com.sanhuai.pojo.QQ;
import com.sanhuai.service.QQService;

import javax.servlet.;
import javax.servlet.http.;
import javax.servlet.annotation.*;
import java.io.IOException;

@WebServlet("/addQQz")
public class addQQ extends HttpServlet
{
private QQService service = new QQService();

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
    String id = request.getParameter("id");
    String name = request.getParameter("aname");
    String password = request.getParameter("password");
    QQ qq = new QQ();
    qq.setId(Integer.parseInt(id));
    qq.setName(name);
    qq.setPassword(password);

    //获取用户输入的验证码
    String checkCode = request.getParameter("checkCode");

    //程序生成的验证码
    HttpSession session = request.getSession();
    String checkCodeGen = (String) session.getAttribute("checkCodeGen");

    if (!checkCodeGen.equalsIgnoreCase(checkCode))
    {
        request.setAttribute("addOneQQ", "验证码错误");
        request.getRequestDispatcher("/register.jsp").forward(request, response);
        return;
    }

    boolean b = service.addQQ(qq);

    if (b)
    {
        //注册成功
        request.setAttribute("addOneQQ", "注册成功,请登录");
        request.getRequestDispatcher("/login.jsp").forward(request, response);
    }
    else
    {
        //注册失败
        request.setAttribute("addOneQQ", "账号已存在,请重新注册");
        request.getRequestDispatcher("/register").forward(request, response);
    }
}

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
    this.doGet(request, response);
}

}

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

欢迎注册

已有帐号？ 登录

            <script>
                document.getElementById("changeImg").onclick = function () {
                    document.getElementById("checkCodeImg").src = "/userLogin/checkCodeServlet?" + new Date().getMilliseconds();
                }
            </script>

        </table>

        <div class="buttons">
            <input value="注 册" type="submit" id="reg_btn">
        </div>
        <br class="clear">
    </form>

</div>

账号	${addOneQQ}
用户名	用户名不太受欢迎
密码	密码格式有误
验证码	https://ask.csdn.net/new#

关键代码没显示出来😂，我简单做个分析，第一如果用的是form方式需要给输入组件name属性，第二如果使用的是ajax提交，看看是否是表单方式提交，欢迎继续咨询或采纳

表单name的值要和getparam的一致