设计用户注册和登录界面，实现用户注册和登录操作。
- 设计用户注册/登录界面;
- 使用工具在MySQL中创建user表，包括学号、姓名、密码、专业、班级；
- 实现注册操作：在user表中插入一条新纪录，但学号不能重复；
- 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：
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;
public class UserRegistrationLogin extends JFrame {
private JTextField studentIdField;
private JPasswordField passwordField;
private JTextField nameField;
private JTextField majorField;
private JTextField classField;
private JComboBox<String> usernameComboBox;
private Connection conn;
public UserRegistrationLogin() {
super("User Registration and Login");
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setSize(400, 300);
this.setLocationRelativeTo(null);
JPanel panel = new JPanel(new GridLayout(6, 2));
JLabel studentIdLabel = new JLabel("Student ID:");
studentIdField = new JTextField();
JLabel passwordLabel = new JLabel("Password:");
passwordField = new JPasswordField();
JLabel nameLabel = new JLabel("Name:");
nameField = new JTextField();
JLabel majorLabel = new JLabel("Major:");
majorField = new JTextField();
JLabel classLabel = new JLabel("Class:");
classField = new JTextField();
JLabel usernameLabel = new JLabel("Username:");
usernameComboBox = new JComboBox<>();
JButton registerButton = new JButton("Register");
JButton loginButton = new JButton("Login");
panel.add(studentIdLabel);
panel.add(studentIdField);
panel.add(passwordLabel);
panel.add(passwordField);
panel.add(nameLabel);
panel.add(nameField);
panel.add(majorLabel);
panel.add(majorField);
panel.add(classLabel);
panel.add(classField);
panel.add(usernameLabel);
panel.add(usernameComboBox);
panel.add(registerButton);
panel.add(loginButton);
this.getContentPane().add(panel);
registerButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
registerUser();
}
});
loginButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
loginUser();
}
});
try {
String driver = "com.mysql.cj.jdbc.Driver";
String url = "jdbc:mysql://localhost/student?user=ly&password=123456";
Class.forName(driver);
conn = DriverManager.getConnection(url);
loadUsernames();
} catch (ClassNotFoundException | SQLException ex) {
ex.printStackTrace();
}
}
private void registerUser() {
String studentId = studentIdField.getText();
String password = new String(passwordField.getPassword());
String name = nameField.getText();
String major = majorField.getText();
String className = classField.getText();
if (studentId.isEmpty() || password.isEmpty() || name.isEmpty() || major.isEmpty() || className.isEmpty()) {
JOptionPane.showMessageDialog(this, "Please fill in all fields");
return;
}
try {
PreparedStatement stmt = conn.prepareStatement("INSERT INTO student (student_id, name, password, major, class) VALUES (?, ?, ?, ?, ?)");
stmt.setString(1, studentId);
stmt.setString(2, name);
stmt.setString(3, password);
stmt.setString(4, major);
stmt.setString(5, className);
stmt.executeUpdate();
JOptionPane.showMessageDialog(this, "Registration successful");
studentIdField.setText("");
passwordField.setText("");
nameField.setText("");
majorField.setText("");
classField.setText("");
loadUsernames();
} catch (SQLException ex) {
JOptionPane.showMessageDialog(this, "Registration failed: " + ex.getMessage());
}
}
private void loginUser() {
String studentId = studentIdField.getText();
String password = new String(passwordField.getPassword());
try {
PreparedStatement stmt = conn.prepareStatement("SELECT * FROM student WHERE student_id = ? AND password = ?");
stmt.setString(1, studentId);
stmt.setString(2, password);
ResultSet rs = stmt.executeQuery();
if (rs.next()) {
String name = rs.getString("name");
JOptionPane.showMessageDialog(this, "Login successful. Welcome, " + name + "!");
// Remember the username for future logins
String selectedUsername = (String) usernameComboBox.getSelectedItem();
if (selectedUsername == null || !selectedUsername.equals(name)) {
usernameComboBox.addItem(name);
usernameComboBox.setSelectedItem(name);
}
studentIdField.setText("");
passwordField.setText("");
} else {
JOptionPane.showMessageDialog(this, "Login failed. Please check your student ID and password.");
}
} catch (SQLException ex) {
JOptionPane.showMessageDialog(this, "Login failed: " + ex.getMessage());
}
}
private void loadUsernames() {
try {
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT DISTINCT name FROM student");
usernameComboBox.removeAllItems();
while (rs.next()) {
String name = rs.getString("name");
usernameComboBox.addItem(name);
}
} catch (SQLException ex) {
ex.printStackTrace();
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
UserRegistrationLogin frame = new UserRegistrationLogin();
frame.setVisible(true);
}
});
}
}
效果展示：
