【通过jdbc连接数据库】

连接数据库

import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DatabaseExample {
    public static void main(String[] args) {
        // 数据库连接信息（请替换为你的实际信息）
        String url = "jdbc:mysql://localhost:3306/your_database";
        String username = "your_username";
        String password = "your_password";
        
        Connection connection = null;
        Statement statement = null;
        ResultSet resultSet = null;
        
        try {
            // 1. 加载数据库驱动（MySQL 8.0+）
            Class.forName("com.mysql.cj.jdbc.Driver");
            
            // 2. 建立数据库连接
            connection = DriverManager.getConnection(url, username, password);
            System.out.println("数据库连接成功！");
            
            // 3. 创建Statement对象
            statement = connection.createStatement();
            
            // 4. 执行SQL查询
            String sql = "SELECT id, name FROM users";
            resultSet = statement.executeQuery(sql);
            
            // 5. 处理结果集
            while (resultSet.next()) {
                int id = resultSet.getInt("id");
                String name = resultSet.getString("name");
                System.out.println("ID: " + id + ", Name: " + name);
            }
            
        } catch (ClassNotFoundException e) {
            System.err.println("找不到数据库驱动！");
            e.printStackTrace();
        } catch (SQLException e) {
            System.err.println("数据库连接失败！");
            e.printStackTrace();
        } finally {
            // 6. 关闭资源（逆序关闭）
            try {
                if (resultSet != null) resultSet.close();
                if (statement != null) statement.close();
                if (connection != null) connection.close();
                System.out.println("数据库连接已关闭");
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}