我是 Spring 框架和 java 的新手。我正在為我的網絡應用程序創建注冊模塊。我創建了 DAO、DTO、Dispatcher Servlet、控制器等等。當我提交表單時，它會將我重定向到我想去的地方，但沒有數據添加到數據庫中。我的用戶DTO.java    package com.lagan.dto;public class userDto{    public String userId;    public String firstName;    public String lastName;    public String birthDate;    public int gender;    public String email;    public String password;    public String getUserId() {        return userId;    }    public String getUserId(String userId) {        return userId;    }    public void setUserId(String userId) {        this.userId = userId;    }    public String getFirstName() {        return firstName;    }    public void setFirstName(String firstName) {        this.firstName = firstName;    }    public String getLastName() {        return lastName;    }    public void setLastName(String lastName) {        this.lastName = lastName;    }    public String getBirthDate() {        return birthDate;    }    public void setBirthDate(String birthDate) {        this.birthDate = birthDate;    }    public int getGender() {        return gender;    }    public void setGender(int gender) {        this.gender = gender;    }    public String getEmail() {        return email;    }    public void setEmail(String email) {        this.email = email;    }    public String getPassword() {        return password;    }    public void setPassword(String password){        this.password = password;    }}userDao.javapackage com.lagan.dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.util.ArrayList;import java.util.List;import com.lagan.dbconnector.dbconnect;import com.lagan.dto.userDto;