如何在不使用Spring/JPA/Hibernate的情况下传递JDBC连接

   <groupId>mysql</groupId>
   <artifactId>mysql-connector-java</artifactId>
   <version>8.0.26</version>
</dependency>

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

public class JdbcConnection {
    private static Connection connection;

    public static Connection getConnection() {
        if (connection == null) {
            try {
                Class.forName("com.mysql.cj.jdbc.Driver");
                connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/your_database_name", "your_username", "your_password");
            } catch (ClassNotFoundException | SQLException e) {
                e.printStackTrace();
            }
        }
        return connection;
    }
}

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

public class UserDao {
    public User getUserById(int id) {
        User user = null;
        try {
            Connection connection = JdbcConnection.getConnection();
            String sql = "SELECT * FROM user WHERE id = ?";
            PreparedStatement preparedStatement = connection.prepareStatement(sql);
            preparedStatement.setInt(1, id);
            ResultSet resultSet = preparedStatement.executeQuery();
            if (resultSet.next()) {
                user = new User();
                user.setId(resultSet.getInt("id"));
                user.setName(resultSet.getString("name"));
                user.setAge(resultSet.getInt("age"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return user;
    }
}

public class Main {
    public static void main(String[] args) {
        UserDao userDao = new UserDao();
        User user = userDao.getUserById(1);
        if (user != null) {
            System.out.println("User ID: " + user.getId());
            System.out.println("User Name: " + user.getName());
            System.out.println("User Age: " + user.getAge());
        } else {
            System.out.println("User not found.");
        }
    }
}