多个库 mysql怎么连接

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

public class MultiDBConnection {
    public static void main(String[] args) {
        String url1 = "jdbc:mysql://localhost:3306/db1";
        String url2 = "jdbc:mysql://localhost:3306/db2";
        String user = "username";
        String password = "password";

        try (Connection conn1 = DriverManager.getConnection(url1, user, password);
             Connection conn2 = DriverManager.getConnection(url2, user, password)) {
            System.out.println("Connected to db1 and db2");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

import mysql.connector

def connect_to_db(host, database, user, password):
    return mysql.connector.connect(
        host=host,
        database=database,
        user=user,
        password=password
    )

db1 = connect_to_db('localhost', 'db1', 'username', 'password')
db2 = connect_to_db('localhost', 'db2', 'username', 'password')

print("Connected to db1 and db2")

String url = "jdbc:mysql://localhost:3306/db?connectTimeout=5000";

GRANT ALL PRIVILEGES ON db1.* TO 'username'@'localhost';
FLUSH PRIVILEGES;