idea中mysql连接失败

URL: jdbc:mysql://localhost:3306/mydatabase
用户名: root
密码: mypassword

mysql -u root -p

SHOW GRANTS FOR 'root'@'localhost';
GRANT ALL PRIVILEGES ON mydatabase.* TO 'root'@'localhost';
FLUSH PRIVILEGES;

sudo service mysql start

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://localhost:3306/mydatabase";
        String user = "root";
        String password = "mypassword";

        try (Connection conn = DriverManager.getConnection(url, user, password)) {
            System.out.println("Connected to the database!");
        } catch (SQLException e) {
            System.out.println("Failed to connect to the database.");
            e.printStackTrace();
        }
    }
}