字符串参数和SELECT为java中的sql准备的语句

import java.sql.*;

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

        try (Connection conn = DriverManager.getConnection(url, username, password)) {
            String sql = "SELECT * FROM users WHERE age > ?";
            int ageThreshold = 18;

            PreparedStatement stmt = conn.prepareStatement(sql);
            stmt.setInt(1, ageThreshold);

            ResultSet rs = stmt.executeQuery();

            while (rs.next()) {
                String name = rs.getString("name");
                int age = rs.getInt("age");
                System.out.println("Name: " + name + ", Age: " + age);
            }

            rs.close();
            stmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}