java swing 连接数据库分页代码

以下是一个简单的Java Swing连接数据库并实现分页的示例代码：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;

public class DatabasePaginationExample extends JFrame {
    
    private static final long serialVersionUID = 1L;
    private static final int PAGE_SIZE = 10;
    private Connection conn;
    private int currentPage = 1;
    private int totalRows;
    private int totalPages;
    private JTable table;
    private DefaultTableModel model;
    
    public DatabasePaginationExample() {
        setTitle("Database Pagination Example");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setSize(600, 400);
        setLocationRelativeTo(null);

        String[] columnNames = {"Name", "Age", "Gender"};
        model = new DefaultTableModel(columnNames, 0);
        table = new JTable(model);
        add(new JScrollPane(table));
        
        connectToDatabase();
        loadPage(currentPage);
        
        setVisible(true);
    }

    private void connectToDatabase() {
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            String url = "jdbc:mysql://localhost:3306/mydatabase";
            String username = "root";
            String password = "password";
            conn = DriverManager.getConnection(url, username, password);
        } catch (ClassNotFoundException | SQLException e) {
            JOptionPane.showMessageDialog(this, e.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
            e.printStackTrace();
        }
    }

    private void loadPage(int page) {
        try {
            String countQuery = "SELECT COUNT(*) FROM employees";
            PreparedStatement countStmt = conn.prepareStatement(countQuery);
            ResultSet countResult = countStmt.executeQuery();
            countResult.next();
            totalRows = countResult.getInt(1);
            totalPages = (int) Math.ceil((double) totalRows / PAGE_SIZE);

            model.setRowCount(0);
            String query = "SELECT * FROM employees LIMIT ?,?";
            PreparedStatement stmt = conn.prepareStatement(query);
            int offset = (page - 1) * PAGE_SIZE;
            stmt.setInt(1, offset);
            stmt.setInt(2, PAGE_SIZE);
            ResultSet result = stmt.executeQuery();
            while (result.next()) {
                String name = result.getString("name");
                int age = result.getInt("age");
                String gender = result.getString("gender");
                model.addRow(new Object[]{name, age, gender});
            }
        } catch (SQLException e) {
            JOptionPane.showMessageDialog(this, e.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
            e.printStackTrace();
        }
    }

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

}

以上代码使用了MySQL数据库作为示例。你需要改变数据库驱动程序的名称、URL、用户名和密码以适应你自己的情况。

在 `loadPage` 方法中，第一个查询获取表的总行数，第二个查询使用 `LIMIT` 和 `OFFSET` 子句来获取当前页的数据行。`offset` 值是当前页数减一乘以每页的行数，它用于计算要跳过的行数。数据检索后，将其添加到表格模型中。

`connectToDatabase` 方法创建了一个 `Connection` 对象，它与数据库建立连接。

在 `main` 方法中，创建了一个 `DatabasePaginationExample` 对象，它创建了一个带有滚动条的表格和两个按钮。每次单击下一页按钮时，当前页面计数器 `currentPage` 增加，然后重新加载该页面。如果尝试加载当前页面之外的页面，会发出警告。