Java连接数据库实现注册与登录界面

好的，这是一个比较常见的需求，下面给您提供一个基于Java Swing和MySQL的简单实现。

首先，您需要在MySQL中创建一个名为"users"的表，表结构如下：

CREATE TABLE users (
  id int(11) NOT NULL AUTO_INCREMENT,
  username varchar(50) NOT NULL,
  password varchar(50) NOT NULL,
  PRIMARY KEY (id)
);

接着，您需要下载并添加MySQL的JDBC驱动程序到您的项目中。您可以在这里下载MySQL的JDBC驱动程序：https://dev.mysql.com/downloads/connector/j/

然后，您需要编写Java代码来连接数据库并实现注册与登录功能。下面是一个简单的示例代码：

import java.sql.*;

public class Database {
    private static final String URL = "jdbc:mysql://localhost:3306/mydatabase";
    private static final String USER = "root";
    private static final String PASSWORD = "password";
    private static Connection conn = null;
    
    public static Connection getConnection() throws SQLException {
        if (conn == null) {
            conn = DriverManager.getConnection(URL, USER, PASSWORD);
        }
        return conn;
    }
}

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;

public class RegisterLogin extends JFrame implements ActionListener {
    private static final long serialVersionUID = 1L;
    private JLabel usernameLabel, passwordLabel;
    private JTextField usernameField;
    private JPasswordField passwordField;
    private JButton loginButton, registerButton;

    public RegisterLogin() {
        setTitle("Login/Register");
        setSize(300, 150);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);

        JPanel panel = new JPanel(new GridLayout(3, 2));
        usernameLabel = new JLabel("Username:");
        usernameField = new JTextField();
        passwordLabel = new JLabel("Password:");
        passwordField = new JPasswordField();
        loginButton = new JButton("Login");
        registerButton = new JButton("Register");

        panel.add(usernameLabel);
        panel.add(usernameField);
        panel.add(passwordLabel);
        panel.add(passwordField);
        panel.add(loginButton);
        panel.add(registerButton);

        add(panel);

        loginButton.addActionListener(this);
        registerButton.addActionListener(this);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == loginButton) {
            try {
                Connection conn = Database.getConnection();
                String query = "SELECT * FROM users WHERE username=? AND password=?";
                PreparedStatement ps = conn.prepareStatement(query);
                ps.setString(1, usernameField.getText());
                ps.setString(2, new String(passwordField.getPassword()));
                ResultSet rs = ps.executeQuery();
                if (rs.next()) {
                    JOptionPane.showMessageDialog(null, "Login successful");
                } else {
                    JOptionPane.showMessageDialog(null, "Invalid username/password");
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        } else if (e.getSource() == registerButton) {
            try {
                Connection conn = Database.getConnection();
                String query = "INSERT INTO users (username, password) VALUES (?,?)";
                PreparedStatement ps = conn.prepareStatement(query);
                ps.setString(1, usernameField.getText());
                ps.setString(2, new String(passwordField.getPassword()));
                ps.executeUpdate();
                JOptionPane.showMessageDialog(null, "Registration successful");
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        new RegisterLogin();
    }
}

在这个示例代码中，我们使用了JDBC连接数据库，并且通过JOptionPane显示了登录和注册的结果。

注意，这只是一个简单的示例，实际项目中您需要更加完善的用户验证和安全性措施。希望对您有所帮助！