dopost调用不了其他方法怎么办

如下图，dopost无法调用定义的userservice方法，doget方法中也无法调用，求解答
在这个类里写了其他方法，都可以调用userservice方法，把dopost（）的形参删除后就可以调用了。唯独带形参的dopost和doget调用不了，太奇怪了

package com.javaweb.web;

import com.javaweb.domain.User;
import com.javaweb.service.UserService;

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


public class RegistServlet01 extends HttpServlet {
    private UserService userService = new UserService();

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        String email = req.getParameter("email");
        String code = req.getParameter("code");

        //验证码正确
        if (code.equalsIgnoreCase("bnbnp")) {
            if (userService.existsUsername(username)) {//用户名存在
                System.out.println(username + password + email + code + "111");
                System.out.println("用户名" + username + "已存在");
                req.getRequestDispatcher("/pages/user/regist.html").forward(req, resp);
            } else {//用户名不存在
                //将信息保存至数据库中
                System.out.println(username + password + email + code + "222");
                userService.registUser(new User(username, password, email));
                System.out.println(username + password + email + code + "333");
                //跳转至注册成功页面
                req.getRequestDispatcher("/pages/user/regist_success.html").forward(req, resp);
            }
        } else {//验证码错误
            System.out.println("验证码 " + code + " 错误");
            req.getRequestDispatcher("/pages/user/regist.html").forward(req, resp);
        }
    }
}

你都post第二行是什么代码？
你调用的是第二行的。

在这个类里写了其他方法，都可以调用userservice方法，把dopost（）的形参删除后就可以调用了。唯独带形参的dopost和doget调用不了，太奇怪了