如何测试mysql连接成功

mysql -h hostname -u username -p

import mysql.connector

try:
    connection = mysql.connector.connect(
        host="hostname",
        user="username",
        password="password"
    )
    if connection.is_connected():
        print("MySQL connection successful")
except mysql.connector.Error as err:
    print(f"Error: '{err}'")
finally:
    if connection.is_connected():
        connection.close()

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

public class MySQLConnectionTest {
    public static void main(String[] args) {
        String url = "jdbc:mysql://hostname:3306/database";
        String user = "username";
        String password = "password";

        try (Connection conn = DriverManager.getConnection(url, user, password)) {
            System.out.println("MySQL connection successful");
        } catch (SQLException e) {
            System.out.println("Error: " + e.getMessage());
        }
    }
}

const mysql = require('mysql');

const connection = mysql.createConnection({
    host: 'hostname',
    user: 'username',
    password: 'password'
});

connection.connect((err) => {
    if (err) {
        console.error('Error: ' + err.stack);
        return;
    }
    console.log('MySQL connection successful');
});

connection.end();