java mysql跨库跨表

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

public class DatabaseConnector {
    private static final String DB_URL1 = "jdbc:mysql://localhost:3306/db1";
    private static final String USER1 = "user1";
    private static final String PASS1 = "password1";

    private static final String DB_URL2 = "jdbc:mysql://localhost:3306/db2";
    private static final String USER2 = "user2";
    private static final String PASS2 = "password2";

    public static Connection getConnection1() throws SQLException {
        return DriverManager.getConnection(DB_URL1, USER1, PASS1);
    }

    public static Connection getConnection2() throws SQLException {
        return DriverManager.getConnection(DB_URL2, USER2, PASS2);
    }
}

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class CrossTableQuery {
    public static void main(String[] args) {
        try (Connection conn = DatabaseConnector.getConnection1();
             Statement stmt = conn.createStatement();
             ResultSet rs = stmt.executeQuery("SELECT t1.column1, t2.column2 FROM table1 t1 JOIN table2 t2 ON t1.id = t2.id")) {

            while (rs.next()) {
                System.out.println(rs.getString("column1") + "\t" + rs.getString("column2"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}