怎么测试mysql数据库能不能连接

mysql -h <hostname> -u <username> -p

import pymysql

try:
    connection = pymysql.connect(host='<hostname>', user='<username>', password='<password>', database='<database>')
    # 连接成功
    connection.close()
except pymysql.Error as e:
    # 连接失败
    print(e)

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

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

        try (Connection connection = DriverManager.getConnection(url, username, password)) {
            // 连接成功
        } catch (SQLException e) {
            // 连接失败
            e.printStackTrace();
        }
    }
}