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
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|\-)[email protected][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：
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。
原文地址：https://www.cnblogs.com/cxy0210/p/11722788.html
时间： 2024-10-09 11:47:59