JAVA登录面板与sql的连接

以下是一个简单的Java登录面板与SQL数据库连接的示例代码：

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

public class LoginPanel extends JFrame implements ActionListener {

    JLabel userLabel, passLabel;
    JTextField userField;
    JPasswordField passField;
    JButton loginButton;

    public LoginPanel() {
        setTitle("Login Panel");
        setSize(300, 150);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        userLabel = new JLabel("Username:");
        passLabel = new JLabel("Password:");
        userField = new JTextField(10);
        passField = new JPasswordField(10);
        loginButton = new JButton("Login");

        JPanel panel = new JPanel();
        panel.add(userLabel);
        panel.add(userField);
        panel.add(passLabel);
        panel.add(passField);
        panel.add(loginButton);
        add(panel);

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

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == loginButton) {
            String username = userField.getText();
            String password = new String(passField.getPassword());

            // Connect to SQL database
            try {
                Class.forName("com.mysql.jdbc.Driver");
                Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/mydatabase", "root", "");
                Statement stmt = conn.createStatement();

                // Execute SQL query
                String sql = "SELECT * FROM users WHERE username='" + username + "' AND password='" + password + "'";
                ResultSet rs = stmt.executeQuery(sql);

                // Check if user exists
                if (rs.next()) {
                    JOptionPane.showMessageDialog(this, "Login successful!");
                } else {
                    JOptionPane.showMessageDialog(this, "Invalid username or password.");
                }

                // Close SQL connection
                rs.close();
                stmt.close();
                conn.close();
            } catch (Exception ex) {
                JOptionPane.showMessageDialog(this, "Error: " + ex.getMessage());
            }
        }
    }

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

在上面的代码中，我们使用了Java Swing库创建了一个简单的登录面板。当用户点击登录按钮时，我们使用JDBC连接到MySQL数据库，并执行一个查询以检查用户名和密码是否匹配。如果匹配，则显示消息框，否则显示错误消息框。请注意，此示例代码仅用于演示目的，实际应用程序需要更多的安全性和验证。