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。