jdbc连接mysql数据库java代码

import java.sql.*;

public class Main {
    public static void main(String[] args) {
        // JDBC连接信息
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String username = "root";
        String password = "password";

        // 定义连接对象、语句对象和结果集对象
        Connection connection = null;
        Statement statement = null;
        ResultSet resultSet = null;

        try {
            // 加载并注册JDBC驱动程序
            Class.forName("com.mysql.cj.jdbc.Driver");

            // 建立数据库连接
            connection = DriverManager.getConnection(url, username, password);

            // 创建Statement对象
            statement = connection.createStatement();

            // 执行SQL查询
            String sql = "SELECT * FROM mytable";
            resultSet = statement.executeQuery(sql);

            // 处理查询结果
            while (resultSet.next()) {
                int id = resultSet.getInt("id");
                String name = resultSet.getString("name");
                System.out.println("ID: " + id + ", Name: " + name);
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            // 释放资源
            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (statement != null) {
                    statement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}