学生信息的添加 Java web简单项目初试（修改）

错误原因：

1.Java web 的Servlet类没有配置好，并且缺少一个 Dao类（Date Access Object通常用于操作数据库的）.

2.代码的某些名称错误，导致数据库数据存储错误。

添加的Dao类如下：

package com.Dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import com.DBUtil.UserDBUtil;

import jdk.nashorn.internal.ir.RuntimeNode.Request;

public class Dao {
    public boolean add(String username,String password,String name,String studentID,String sex,String phone,String email,String xueyuan,String xi,String classes,String year,String shengyuandi,String beizhu) {
        String sql = "insert into use02  values ('" + username + "','" + password +"','" + name +"','" +studentID +"','" + sex +"','" +phone +"','" + email +"','" +xueyuan +"','"+xi +"','"+classes +"','"+year+"','"+shengyuandi +"','"+beizhu +"')";
         // 创建数据库链接
        Connection conn = UserDBUtil.getConnection();
        Statement state = null;
        boolean f = false;
        int a = 0;
        try {
            state = conn.createStatement();
            a = state.executeUpdate(sql);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
             // 关闭z 连接
            //DB.close(state, conn);
        }

        if (a > 0) {
            f = true;
        }
        return f;
    }
}

修改后的Servlet代码如下：

import java.io.IOException;


import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.Dao.*;
import com.DBUtil.*;

/**
 * Servlet implementation class UserServlet
 */
@WebServlet("/AddServlet")
public class AddServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public AddServlet() {
        super();
        // TODO Auto-generated constructor stub
    }
    Dao dao = new Dao();
    
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        String method = req.getParameter("method");
        if ("add".equals(method)) {
            
            add(req, resp);
            System.out.println("!!!");
        }
    }
    private void add(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException {
        // TODO Auto-generated method stub
        String username = req.getParameter("username");
         String password = req.getParameter("password");
        String name = req.getParameter("name");
        String studentID = req.getParameter("studentID");
        String sex = req.getParameter("sex");
        String phone = req.getParameter("phone");
        String email = req.getParameter("email");
        String xueyuan = req.getParameter("xueyuan");
        String xi = req.getParameter("xi");
        String classes = req.getParameter("classes");
        String year = req.getParameter("year");
        String shengyuandi = req.getParameter("shengyuandi");
        String beizhu = req.getParameter("beizhu");
        if(dao.add(username,password,name,studentID,sex,phone,email,xueyuan,xi,classes,year,shengyuandi,beizhu)) {
            req.setAttribute("message", "注册成功!");
            req.getRequestDispatcher("index1.jsp").forward(req, resp);
            return;
        }else {
            req.setAttribute("message", "账号重复，请重新输入!");
            req.getRequestDispatcher("index1.jsp").forward(req, resp);
            return;
        }
        //req.getRequestDispatcher("index1.jsp").forward(req, resp);
    }


}

bean类

public class User {
    private String username;
    private String password;
    private String name;
    private String studentID;
    private String sex;
    private String phone;
    private String email;
    private String xueyuan;
    private String xi;
    private String classes;
    private String year;
    private String shengyuandi;
    private String beizhu;
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getStudentID() {
        return studentID;
    }
    public void setStudentID(String studentID) {
        this.studentID = studentID;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getXueyuan() {
        return xueyuan;
    }
    public void setXueyuan(String xueyuan) {
        this.xueyuan = xueyuan;
    }
    public String getXi() {
        return xi;
    }
    public void setXi(String xi) {
        this.xi = xi;
    }
    public String getClasses() {
        return classes;
    }
    public void setClasses(String classes) {
        this.classes = classes;
    }
    public String getYear() {
        return year;
    }
    public void setYear(String year) {
        this.year = year;
    }
    public String getShengyuandi() {
        return shengyuandi;
    }
    public void setShengyuandi(String shengyuandi) {
        this.shengyuandi = shengyuandi;
    }
    public String getBeizhu() {
        return beizhu;
    }
    public void setBeizhu(String beizhu) {
        this.beizhu = beizhu;
    }
    public User(String username, String password, String name, String studentID, String sex, String phone, String email,
            String xueyuan, String xi, String classes, String year, String shengyuandi, String beizhu) {
        super();
        this.username = username;
        this.password = password;
        this.name = name;
        this.studentID = studentID;
        this.sex = sex;
        this.phone = phone;
        this.email = email;
        this.xueyuan = xueyuan;
        this.xi = xi;
        this.classes = classes;
        this.year = year;
        this.shengyuandi = shengyuandi;
        this.beizhu = beizhu;
    }
    
    

}

数据库连接程序：

import java.sql.Connection;

import java.sql.DriverManager;
//import java.sql.ResultSet;
import java.sql.SQLException;
//import java.sql.Statement;

public class UserDBUtil {
    static Connection con;
    public static Connection getConnection() {
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            System.out.println("数据库驱动加载成功");
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        try {
            con=DriverManager.getConnection("jdbc:mysql://localhost:3306/user?useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B88&serverTimezone=GMT%2B8&useSSL=false","root","101032");
            System.out.println("数据库链接成功！");
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        return con;
        }
    
     public static void main(String[] args) {
         UserDBUtil c=new UserDBUtil();
         c.getConnection();
        
    }

jsp 页面源代码实现：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>用户注册</title>
</head>
<body>

<script type="text/javascript" src="./js/jquery-3.3.1.min.js"></script>

<div class="container">
    <section>
        <form action="AddServlet?method=add" method="post" onsubmit="return check(this)">        
            <span class="username">登陆账号</span>
                <input type="text" name="username" placeholder="  username" id="username">
            <br/>
            
            <span class="password">登陆密码</span>
            <input type="password" name="password" placeholder="  password" id="password">
            <br/>
            
            <span class="name">姓名</span>
                <input type="text" name="name" placeholder="  name" id="name">
            <br/>
            
            <span class="studentID">学号</span>
            <input type="text" name="studentID" placeholder="  studentID" id="studentID" >
            <br/>
            
            <span class="sex">性别</span>
                <input type="radio" name="sex" id="sexnan" value="M">男
                &nbsp;
                <input type="radio" name="sex" id="sexnv" value="F">女
            <br/>
            
<!--             <span class="diqu">地区</span> -->
<!--             <select name="diqu"> -->
<!--                   <option value ="北京市">北京市</option> -->
<!--                   <option value ="天津市">天津市</option> -->
<!--                   <option value="河北省">河北省</option> -->
<!--             </select> -->
<!--             <br/> -->
            
            <span class="phone">手机号</span>
                <input type="text" name="phone" placeholder="  phone" id="phone">
            <br/>
            
            <span class="email">邮箱</span>
                <input type="text" name="email" placeholder="  email" id="email">
            <br/>
            
            <span class="xueyuan">所在学院：</span>
            <input type="text" name="xueyuan" placeholder="  xueyuan" id="xueyuan">
            <br/>
            
            <span class="xi">所在系：</span>
            <input type="text" name="xi" placeholder="  suozaixi" id="xi">
            <br/>
            
            <span class="classes">所在班级：</span>
            <input type="text" name="classes" placeholder="  classes" id="classes">
            <br/>
            
            
            <span class="year">入学年份（届）：</span>
            <select name="year">
            <option value ="2014">2014</option>
                  <option value ="2015">2015</option>
                  <option value ="2016">2016</option>
                  <option value="2017">2017</option>
                  <option value="2018">2018</option>
                  <option value ="2019">2019</option>
                  </select>
            <br/>
            
            <span class="shengyuandi">生源地：</span>
            <input type="text" name="shengyuandi" placeholder="  shengyuandi" id="shengyuandi">
            <br/>
            
            <span class="beizhu">备注：</span>
            <input type="text" name="beizhu" placeholder="  beizhu" id="beizhu">
            <br/>
            
            <input type="submit" value="保存" class="butn">
<!--             <input type="reset" value="重置" class="butn"> -->
            <br/>
        </form>
    </section>
</div>

<script>
    //正则表达式
function check(form){

    if(form.username.value.length<6 || form.username.value.length>12 || new RegExp("[^0-9a-zA-Z]").test(form.username.value)){
        alert("登陆账号必须由6-12位英文字符或数字组成！");
        form.user.focus();
        return false;
    }
    if(new RegExp("[^a-zA-Z]").test(form.username.value.substring(0,1))){
        alert("登陆账号必须以英文字母开头！");
        form.user.focus();
        return false;
    }
    if(form.password.value.length <= 8 || new RegExp("[^0-9a-zA-Z]").test(form.password.value)){
        alert("密码必须由八位以上字母、数字组成！");
        form.phone.focus();
        return false;
    }
    if(form.studentID.value.length != 8 || new RegExp("[^0-9]").test(form.studentID.value)){
        alert("请输入八位学号！");
        form.phone.focus();
        return false;
    }

    if(form.phone.value.length != 11 || new RegExp("[^0-9]").test(form.phone.value)){
        alert("手机号请输入11位数字！");
        form.phone.focus();
        return false;
    }

    //以数字字母开头，中间可以是多个数字字母或下划线；然后是“@”；然后是数字字母；然后是“.”；最后是2-4个字母结尾
    var regex = /^([a-zA-Z]|[0-9])(w|-)+@[a-zA-Z0-9]+.([a-zA-Z]{2,4})$/;
    if(!regex.test(form.email.value)){
        alert("邮箱格式错误！");
        form.email.focus();
        return false;
    }
    return true;
}
</script>

</body>
</html>

数据库存储界面：

对于Java web数据库连接的理解：

Java类：

1.servlet 类 处理从前端接受的信息，即jsp 与数据库连接的接口

 2.DBUtil 类  加载数据库驱动， 建立对数据库的连接。

3.Dao 类  实现对数据库的增删改查

4.Bean 类 存储信息的基础类

5.在lib目录下导入需要的jar的包

 6. jsp 实现界面。

本人目前处于初学阶段，代码大部分都是对模板进行修改，没有完全理解，仍旧有许多需要学习的地方。

 数据库的JDBC桥接：

面向对象的应用程序接口，制定了统一的访问各种关系型数据库的标准接口。

JDBC任务：

1.与数据库建立连接

2.向数据库发生sql语句

3.处理从数据库返回的结果

以下是之前的错误代码：

https://www.cnblogs.com/cxy0210/p/11715924.html

以上代码如有错误，敬请指正，感激不尽。