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：

 1 package com.Dao;
 2 
 3 import java.sql.Connection;
 4 import java.sql.PreparedStatement;
 5 import java.sql.ResultSet;
 6 import java.sql.SQLException;
 7 import java.sql.Statement;
 8 import java.util.ArrayList;
 9 import java.util.List;
10 import com.DBUtil.UserDBUtil;
11 
12 import jdk.nashorn.internal.ir.RuntimeNode.Request;
13 
14 public class Dao {
15     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) {
16         String sql = "insert into use02  values ('" + username + "','" + password +"','" + name +"','" +studentID +"','" + sex +"','" +phone +"','" + email +"','" +xueyuan +"','"+xi +"','"+classes +"','"+year+"','"+shengyuandi +"','"+beizhu +"')";
17          // 创建数据库链接
18         Connection conn = UserDBUtil.getConnection();
19         Statement state = null;
20         boolean f = false;
21         int a = 0;
22         try {
23             state = conn.createStatement();
24             a = state.executeUpdate(sql);
25         } catch (Exception e) {
26             e.printStackTrace();
27         } finally {
28              // 关闭z 连接
29             //DB.close(state, conn);
30         }
31 
32         if (a > 0) {
33             f = true;
34         }
35         return f;
36     }
37 }

修改后的Servlet代码如下：

 1 import java.io.IOException;
 2 
 3 
 4 import javax.servlet.ServletException;
 5 import javax.servlet.ServletRequest;
 6 import javax.servlet.annotation.WebServlet;
 7 import javax.servlet.http.HttpServlet;
 8 import javax.servlet.http.HttpServletRequest;
 9 import javax.servlet.http.HttpServletResponse;
10 
11 import com.Dao.*;
12 import com.DBUtil.*;
13 
14 /**
15  * Servlet implementation class UserServlet
16  */
17 @WebServlet("/AddServlet")
18 public class AddServlet extends HttpServlet {
19     private static final long serialVersionUID = 1L;
20        
21     /**
22      * @see HttpServlet#HttpServlet()
23      */
24     public AddServlet() {
25         super();
26         // TODO Auto-generated constructor stub
27     }
28     Dao dao = new Dao();
29     
30     protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
31         req.setCharacterEncoding("utf-8");
32         String method = req.getParameter("method");
33         if ("add".equals(method)) {
34             
35             add(req, resp);
36             System.out.println("!!!");
37         }
38     }
39     private void add(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException {
40         // TODO Auto-generated method stub
41         String username = req.getParameter("username");
42          String password = req.getParameter("password");
43         String name = req.getParameter("name");
44         String studentID = req.getParameter("studentID");
45         String sex = req.getParameter("sex");
46         String phone = req.getParameter("phone");
47         String email = req.getParameter("email");
48         String xueyuan = req.getParameter("xueyuan");
49         String xi = req.getParameter("xi");
50         String classes = req.getParameter("classes");
51         String year = req.getParameter("year");
52         String shengyuandi = req.getParameter("shengyuandi");
53         String beizhu = req.getParameter("beizhu");
54         if(dao.add(username,password,name,studentID,sex,phone,email,xueyuan,xi,classes,year,shengyuandi,beizhu)) {
55             req.setAttribute("message", "注册成功!");
56             req.getRequestDispatcher("index1.jsp").forward(req, resp);
57             return;
58         }else {
59             req.setAttribute("message", "账号重复，请重新输入!");
60             req.getRequestDispatcher("index1.jsp").forward(req, resp);
61             return;
62         }
63         //req.getRequestDispatcher("index1.jsp").forward(req, resp);
64     }
65 
66 
67 }

bean类

  1 public class User {
  2     private String username;
  3     private String password;
  4     private String name;
  5     private String studentID;
  6     private String sex;
  7     private String phone;
  8     private String email;
  9     private String xueyuan;
 10     private String xi;
 11     private String classes;
 12     private String year;
 13     private String shengyuandi;
 14     private String beizhu;
 15     public String getUsername() {
 16         return username;
 17     }
 18     public void setUsername(String username) {
 19         this.username = username;
 20     }
 21     public String getPassword() {
 22         return password;
 23     }
 24     public void setPassword(String password) {
 25         this.password = password;
 26     }
 27     public String getName() {
 28         return name;
 29     }
 30     public void setName(String name) {
 31         this.name = name;
 32     }
 33     public String getStudentID() {
 34         return studentID;
 35     }
 36     public void setStudentID(String studentID) {
 37         this.studentID = studentID;
 38     }
 39     public String getSex() {
 40         return sex;
 41     }
 42     public void setSex(String sex) {
 43         this.sex = sex;
 44     }
 45     public String getPhone() {
 46         return phone;
 47     }
 48     public void setPhone(String phone) {
 49         this.phone = phone;
 50     }
 51     public String getEmail() {
 52         return email;
 53     }
 54     public void setEmail(String email) {
 55         this.email = email;
 56     }
 57     public String getXueyuan() {
 58         return xueyuan;
 59     }
 60     public void setXueyuan(String xueyuan) {
 61         this.xueyuan = xueyuan;
 62     }
 63     public String getXi() {
 64         return xi;
 65     }
 66     public void setXi(String xi) {
 67         this.xi = xi;
 68     }
 69     public String getClasses() {
 70         return classes;
 71     }
 72     public void setClasses(String classes) {
 73         this.classes = classes;
 74     }
 75     public String getYear() {
 76         return year;
 77     }
 78     public void setYear(String year) {
 79         this.year = year;
 80     }
 81     public String getShengyuandi() {
 82         return shengyuandi;
 83     }
 84     public void setShengyuandi(String shengyuandi) {
 85         this.shengyuandi = shengyuandi;
 86     }
 87     public String getBeizhu() {
 88         return beizhu;
 89     }
 90     public void setBeizhu(String beizhu) {
 91         this.beizhu = beizhu;
 92     }
 93     public User(String username, String password, String name, String studentID, String sex, String phone, String email,
 94             String xueyuan, String xi, String classes, String year, String shengyuandi, String beizhu) {
 95         super();
 96         this.username = username;
 97         this.password = password;
 98         this.name = name;
 99         this.studentID = studentID;
100         this.sex = sex;
101         this.phone = phone;
102         this.email = email;
103         this.xueyuan = xueyuan;
104         this.xi = xi;
105         this.classes = classes;
106         this.year = year;
107         this.shengyuandi = shengyuandi;
108         this.beizhu = beizhu;
109     }
110     
111     
112 
113 }

数据库连接程序：

 1 import java.sql.Connection;
 2 
 3 import java.sql.DriverManager;
 4 //import java.sql.ResultSet;
 5 import java.sql.SQLException;
 6 //import java.sql.Statement;
 7 
 8 public class UserDBUtil {
 9     static Connection con;
10     public static Connection getConnection() {
11         try {
12             Class.forName("com.mysql.cj.jdbc.Driver");
13             System.out.println("数据库驱动加载成功");
14         } catch (ClassNotFoundException e) {
15             // TODO Auto-generated catch block
16             e.printStackTrace();
17         }
18         
19         try {
20             con=DriverManager.getConnection("jdbc:mysql://localhost:3306/user?useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B88&serverTimezone=GMT%2B8&useSSL=false","root","101032");
21             System.out.println("数据库链接成功！");
22         } catch (SQLException e) {
23             // TODO Auto-generated catch block
24             e.printStackTrace();
25         }
26         
27         return con;
28         }
29     
30      public static void main(String[] args) {
31          UserDBUtil c=new UserDBUtil();
32          c.getConnection();
33         
34     }

jsp 页面源代码实现：

  1 <%@ page language="java" contentType="text/html; charset=UTF-8"
  2     pageEncoding="UTF-8"%>
  3 <!DOCTYPE html>
  4 <html>
  5 <head>
  6 <meta charset="UTF-8">
  7 <title>用户注册</title>
  8 </head>
  9 <body>
 10 
 11 <script type="text/javascript" src="./js/jquery-3.3.1.min.js"></script>
 12 
 13 <div class="container">
 14     <section>
 15         <form action="AddServlet?method=add" method="post" onsubmit="return check(this)">        
 16             <span class="username">登陆账号</span>
 17                 <input type="text" name="username" placeholder="  username" id="username">
 18             <br/>
 19             
 20             <span class="password">登陆密码</span>
 21             <input type="password" name="password" placeholder="  password" id="password">
 22             <br/>
 23             
 24             <span class="name">姓名</span>
 25                 <input type="text" name="name" placeholder="  name" id="name">
 26             <br/>
 27             
 28             <span class="studentID">学号</span>
 29             <input type="text" name="studentID" placeholder="  studentID" id="studentID" >
 30             <br/>
 31             
 32             <span class="sex">性别</span>
 33                 <input type="radio" name="sex" id="sexnan" value="M">男
 34                 &nbsp;
 35                 <input type="radio" name="sex" id="sexnv" value="F">女
 36             <br/>
 37             
 38 <!--             <span class="diqu">地区</span> -->
 39 <!--             <select name="diqu"> -->
 40 <!--                   <option value ="北京市">北京市</option> -->
 41 <!--                   <option value ="天津市">天津市</option> -->
 42 <!--                   <option value="河北省">河北省</option> -->
 43 <!--             </select> -->
 44 <!--             <br/> -->
 45             
 46             <span class="phone">手机号</span>
 47                 <input type="text" name="phone" placeholder="  phone" id="phone">
 48             <br/>
 49             
 50             <span class="email">邮箱</span>
 51                 <input type="text" name="email" placeholder="  email" id="email">
 52             <br/>
 53             
 54             <span class="xueyuan">所在学院：</span>
 55             <input type="text" name="xueyuan" placeholder="  xueyuan" id="xueyuan">
 56             <br/>
 57             
 58             <span class="xi">所在系：</span>
 59             <input type="text" name="xi" placeholder="  suozaixi" id="xi">
 60             <br/>
 61             
 62             <span class="classes">所在班级：</span>
 63             <input type="text" name="classes" placeholder="  classes" id="classes">
 64             <br/>
 65             
 66             
 67             <span class="year">入学年份（届）：</span>
 68             <select name="year">
 69             <option value ="2014">2014</option>
 70                   <option value ="2015">2015</option>
 71                   <option value ="2016">2016</option>
 72                   <option value="2017">2017</option>
 73                   <option value="2018">2018</option>
 74                   <option value ="2019">2019</option>
 75                   </select>
 76             <br/>
 77             
 78             <span class="shengyuandi">生源地：</span>
 79             <input type="text" name="shengyuandi" placeholder="  shengyuandi" id="shengyuandi">
 80             <br/>
 81             
 82             <span class="beizhu">备注：</span>
 83             <input type="text" name="beizhu" placeholder="  beizhu" id="beizhu">
 84             <br/>
 85             
 86             <input type="submit" value="保存" class="butn">
 87 <!--             <input type="reset" value="重置" class="butn"> -->
 88             <br/>
 89         </form>
 90     </section>
 91 </div>
 92 
 93 <script>
 94     //正则表达式
 95 function check(form){
 96 
 97     if(form.username.value.length<6 || form.username.value.length>12 || new RegExp("[^0-9a-zA-Z]").test(form.username.value)){
 98         alert("登陆账号必须由6-12位英文字符或数字组成！");
 99         form.user.focus();
100         return false;
101     }
102     if(new RegExp("[^a-zA-Z]").test(form.username.value.substring(0,1))){
103         alert("登陆账号必须以英文字母开头！");
104         form.user.focus();
105         return false;
106     }
107     if(form.password.value.length <= 8 || new RegExp("[^0-9a-zA-Z]").test(form.password.value)){
108         alert("密码必须由八位以上字母、数字组成！");
109         form.phone.focus();
110         return false;
111     }
112     if(form.studentID.value.length != 8 || new RegExp("[^0-9]").test(form.studentID.value)){
113         alert("请输入八位学号！");
114         form.phone.focus();
115         return false;
116     }
117 
118     if(form.phone.value.length != 11 || new RegExp("[^0-9]").test(form.phone.value)){
119         alert("手机号请输入11位数字！");
120         form.phone.focus();
121         return false;
122     }
123 
124     //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
125     var regex = /^([a-zA-Z]|[0-9])(\w|\-)+@[a-zA-Z0-9]+\.([a-zA-Z]{2,4})$/;
126     if(!regex.test(form.email.value)){
127         alert("邮箱格式错误！");
128         form.email.focus();
129         return false;
130     }
131     return true;
132 }
133 </script>
134 
135 </body>
136 </html>

数据库存储界面：

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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。

学生信息的添加 Java web简单项目初试（修改）

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