java实验：数据库应用（idea+mysql+php)设计用户注册和登录

设计用户注册和登录界面，实现用户注册和登录操作。

1. 设计用户注册/登录界面;
2. 使用工具在MySQL中创建user表，包括学号、姓名、密码、专业、班级；
3. 实现注册操作：在user表中插入一条新纪录，但学号不能重复；
4. 实现登录操作：使用输入的学号和密码在user表中查找，查找成功，弹出消息框显示“登录成功”，不成功，则回到输入界面；使用对象文件记住在本机登录的用户名，显示在用户名组合框中。

因为我是使用的php和Navicat for MySQL创建数据库（电脑上最好不要下载两个版本的mysql，否则会出现问题），而如果使用MySQL Installer for Windows来进行数据库设计，大家可以点击下面这个链接，这个博主大大写的超详细。(个人觉得Navicat for MySQL更方便，数据操作比较简单）。如果说之前没有安装过phpstudy，那就最好跟着下面这个博主尝试一下。

在Windows上配置MySql开发java，导入JDBC的jar包后连接SQL Server数据库&结合Java和MySql的一些简单实践-CSDN博客

一、首先去官网下载mysql和phpstudy。

这两个建议一起下，接着是配置环境，可以搜一下配置教程。

二、

启动如上图所示的mysql和apache服务。

三、

点击创建数据库。

根据提示填写，我这里的数据库名称是student,用户名ly，密码123456，最后点击确认。

接着转到mysql,

找到连接，点击mysql,会有一下窗户：

就依次按刚创建的数据库填写连接名，用户名，密码，其他不用改动，点击确定。

四、打开创建好的连接，新建表

点击保存。

继续保存，ctrl+s。

五、代码部分

代码是在idea中编写，首先要下载驱动文件mysql-connector-j-8.2.0.jar，mysql-connector-java下载_在下是小白的博客-CSDN博客

下载之后，把mysql-connector-j-8.2.0.jar复制到项目中

点击project structure,进入找到modules,点加号选第一个。

找到刚刚导入的mysql-connector-j-8.2.0.jar，双击点ok就可以了。

然后新建类粘贴一下代码：

1. import javax.swing.*;
2. import java.awt.*;
3. import java.awt.event.ActionEvent;
4. import java.awt.event.ActionListener;
5. import java.sql.*;
7. public class UserRegistrationLogin extends JFrame {
8. private JTextField studentIdField;
9. private JPasswordField passwordField;
10. private JTextField nameField;
11. private JTextField majorField;
12. private JTextField classField;
13. private JComboBox usernameComboBox;
15. private Connection conn;
17. public UserRegistrationLogin() {
18. super("User Registration and Login");
19. this.setDefaultCloseOperation(EXIT_ON_CLOSE);
20. this.setSize(400, 300);
21. this.setLocationRelativeTo(null);
23. JPanel panel = new JPanel(new GridLayout(6, 2));
25. JLabel studentIdLabel = new JLabel("Student ID:");
26. studentIdField = new JTextField();
27. JLabel passwordLabel = new JLabel("Password:");
28. passwordField = new JPasswordField();
29. JLabel nameLabel = new JLabel("Name:");
30. nameField = new JTextField();
31. JLabel majorLabel = new JLabel("Major:");
32. majorField = new JTextField();
33. JLabel classLabel = new JLabel("Class:");
34. classField = new JTextField();
35. JLabel usernameLabel = new JLabel("Username:");
36. usernameComboBox = new JComboBox<>();
38. JButton registerButton = new JButton("Register");
39. JButton loginButton = new JButton("Login");
41. panel.add(studentIdLabel);
42. panel.add(studentIdField);
43. panel.add(passwordLabel);
44. panel.add(passwordField);
45. panel.add(nameLabel);
46. panel.add(nameField);
47. panel.add(majorLabel);
48. panel.add(majorField);
49. panel.add(classLabel);
50. panel.add(classField);
51. panel.add(usernameLabel);
52. panel.add(usernameComboBox);
53. panel.add(registerButton);
54. panel.add(loginButton);
56. this.getContentPane().add(panel);
58. registerButton.addActionListener(new ActionListener() {
59. @Override
60. public void actionPerformed(ActionEvent e) {
61. registerUser();
62. }
63. });
65. loginButton.addActionListener(new ActionListener() {
66. @Override
67. public void actionPerformed(ActionEvent e) {
68. loginUser();
69. }
70. });
72. try {
73. String driver = "com.mysql.cj.jdbc.Driver";
74. String url = "jdbc:mysql://localhost/student?user=ly&password=123456";
75. Class.forName(driver);
76. conn = DriverManager.getConnection(url);
78. loadUsernames();
79. } catch (ClassNotFoundException | SQLException ex) {
80. ex.printStackTrace();
81. }
82. }
84. private void registerUser() {
85. String studentId = studentIdField.getText();
86. String password = new String(passwordField.getPassword());
87. String name = nameField.getText();
88. String major = majorField.getText();
89. String className = classField.getText();
91. if (studentId.isEmpty() || password.isEmpty() || name.isEmpty() || major.isEmpty() || className.isEmpty()) {
92. JOptionPane.showMessageDialog(this, "Please fill in all fields");
93. return;
94. }
96. try {
97. PreparedStatement stmt = conn.prepareStatement("INSERT INTO student (student_id, name, password, major, class) VALUES (?, ?, ?, ?, ?)");
98. stmt.setString(1, studentId);
99. stmt.setString(2, name);
100. stmt.setString(3, password);
101. stmt.setString(4, major);
102. stmt.setString(5, className);
103. stmt.executeUpdate();
105. JOptionPane.showMessageDialog(this, "Registration successful");
107. studentIdField.setText("");
108. passwordField.setText("");
109. nameField.setText("");
110. majorField.setText("");
111. classField.setText("");
113. loadUsernames();
114. } catch (SQLException ex) {
115. JOptionPane.showMessageDialog(this, "Registration failed: " + ex.getMessage());
116. }
117. }
119. private void loginUser() {
120. String studentId = studentIdField.getText();
121. String password = new String(passwordField.getPassword());
123. try {
124. PreparedStatement stmt = conn.prepareStatement("SELECT * FROM student WHERE student_id = ? AND password = ?");
125. stmt.setString(1, studentId);
126. stmt.setString(2, password);
127. ResultSet rs = stmt.executeQuery();
129. if (rs.next()) {
130. String name = rs.getString("name");
131. JOptionPane.showMessageDialog(this, "Login successful. Welcome, " + name + "!");
133. // Remember the username for future logins
134. String selectedUsername = (String) usernameComboBox.getSelectedItem();
135. if (selectedUsername == null || !selectedUsername.equals(name)) {
136. usernameComboBox.addItem(name);
137. usernameComboBox.setSelectedItem(name);
138. }
140. studentIdField.setText("");
141. passwordField.setText("");
142. } else {
143. JOptionPane.showMessageDialog(this, "Login failed. Please check your student ID and password.");
144. }
145. } catch (SQLException ex) {
146. JOptionPane.showMessageDialog(this, "Login failed: " + ex.getMessage());
147. }
148. }
150. private void loadUsernames() {
151. try {
152. Statement stmt = conn.createStatement();
153. ResultSet rs = stmt.executeQuery("SELECT DISTINCT name FROM student");
155. usernameComboBox.removeAllItems();
156. while (rs.next()) {
157. String name = rs.getString("name");
158. usernameComboBox.addItem(name);
159. }
160. } catch (SQLException ex) {
161. ex.printStackTrace();
162. }
163. }
165. public static void main(String[] args) {
166. SwingUtilities.invokeLater(new Runnable() {
167. @Override
168. public void run() {
169. UserRegistrationLogin frame = new UserRegistrationLogin();
170. frame.setVisible(true);
171. }
172. });
173. }
174. }

效果展示：