How could i connect with Google cloud instance without app engine

Question

I´m trying to connect to a google cloud instance, but havong some trouble with it. I´d appreciate help to find the easiest way to do so.

Also I´m New to working with Databases and Java.

here is my code:

package com.google.cloud.sql.mysql;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
* A sample app that connects to a Cloud SQL instance and lists all available 
tables in a database.
 */
public class example{
  public static void main(String[] args) throws IOException, SQLException {
// TODO: fill this in
// The instance connection name can be obtained from the instance overview page in Cloud Console
// or by running "gcloud sql instances describe <instance> | grep connectionName".
String instanceConnectionName = "eco-codex-216813:asia-southeast1:instance1";

// TODO: fill this in
// The database from which to list tables.
String databaseName = "mysql";

String username = "root";

// TODO: fill this in
// This is the password that was set via the Cloud Console or empty if never set
// (not recommended).
String password = "1412";


//[START doc-example]
String jdbcUrl = String.format(
    "jdbc:mysql://google/%s?cloudSqlInstance=%s"
        + "&socketFactory=com.google.cloud.sql.mysql.SocketFactory&useSSL=false",
    databaseName,
    instanceConnectionName);

Connection connection = DriverManager.getConnection(jdbcUrl, username, password);


try (Statement statement = connection.createStatement()) {
  ResultSet resultSet = statement.executeQuery("SHOW TABLES");
  while (resultSet.next()) {
    System.out.println(resultSet.getString(1));
    }
   }
  }
}

but i got this error :

<i>
run:
Exception in thread "main" java.sql.SQLNonTransientConnectionException: Cannot connect to MySQL server on google:3,306.

Make sure that there is a MySQL server running on the machine/port you are trying to connect to and that the machine this software is running on is able to connect to this host/port (i.e. not firewalled). Also make sure that the server has not been started with the --skip-networking flag.


    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73)
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:470)
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:207)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at com.google.cloud.sql.mysql.example.main(example.java:45)
Caused by: java.lang.NullPointerException
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:976)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:822)
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456)
    ... 5 more
C:\Users\Zack\AppData\Local\NetBeans\Cache\8.2\executor-snippets\run.xml:53: Java returned: 1
BUILD FAILED (total time: 1 second)</i>

im using NetBeans IDE and using mysql connector java 8.

Answer 1

Welcome to Stackoverflow and Google Cloud! I assume you mean Google Cloud SQL Instance with MySQL engine with "Google cloud instance". You need to open network level access from the machine running the Java program to the Cloud SQL Instance. In Cloud SQL the default behavior is to block this access from outside. You can edit the instance in the cloud console and in "Authorize network" part add your IP address or IP range to allow connection from.

If there is no other firewalls between your Java machine and Cloud SQL, you should be able to connect after this change. Hope it helps!

You can find more information on Cloud SQL connectivity from this page: https://cloud.google.com/sql/docs/mysql/connect-external-app#appaccessIP . You can also find other options for connecting to db, eg with a proxy.