I've been recently trying to connect to a hosted MySQL using Java but can't get it to work. I can connect to a local MySQL with localhost using:
connect = DriverManager.getConnection("jdbc:mysql://localhost/lego?"
+ "user=******&password=*******");
(Replacing the astrisks withmy username and password)
I can connect to the hosted MySQL database fine with PHP using:
mysql_connect('mysql.hosts.co.uk','******','**********');
mysql_select_db('test');
My problem is, I cannot connect via Java. I have an Exception which is caught if the connection doesn't work and this is always printed out.
Any ideas why it isn't working? Am I doing something wrong?
Thanks for your time,
InfinitiFizz
since it works in php (i guess you didn't try to connect from a local place with php???) it shouldn't be a port problem... but you should check that port 3306 is open... and ask the hosts company about that.
Have you noticed that in the DriverManager
http://java.sun.com/javase/6/docs/api/java/sql/DriverManager.html
you have:
getConnection(String url)
but also:
getConnection(String url, String user, String password)
Perhaps it would work better...
My guess is that you need to select a non-standard port, since I'd imagine the hosting server is serving lots of MySQL instances and they can't all use the normal one. I don't see selection of a port here.
If that's not it, perhaps there is a firewall issue somewhere along the way that's blocking the port or connection.
Related
I am trying to connect to H2 Server started on the same machine using java. I started the H2 server in mixed mode. While connecting to the server I am getting Error.
The code to start the server is:
Server.createTcpServer("-tcp", "-tcpAllowOthers", "-tcpSSL").start();
The code to connect to the server is:
Class.forName("org.h2.Driver");
Connection conn = DriverManager.getConnection("jdbc:h2:tcp://127.0.0.1/~/Data/test", "", "");
The Error is:
Connection is broken: "unexpected status 352518912" [90067-197]
Anybody please help me with this. I am stuck at this for two days.
You need to use ssl protocol instead of tcp in the URL, because you use an encrypted socked on the server.
"jdbc:h2:ssl://127.0.0.1/~/Data/test"
Please also note that database cannot be created remotely by default in recent versions of H2 due to security reasons. You need to create the database on the server side with a local url such as "jdbc:h2:~/Data/test", it's enough to open and close a connection to it.
Also I hope that empty password is only for that example code in the question. If you have a database that has an user with ADMIN privileges (username and password from the first connection that creates the database are used to create such user) and an empty or weak password (or if you enable the remote database creation), anyone, who can connect to that port, will get full access to your server process and this process most likely already has the same access to your system as you, so you effectively create a remote security hole with -tcpAllowOthers and such passwords.
I am trying to write a Java desktop app that can connect to my database made with Microsoft SQL Server Manager to allow me to view and update it. But, I am having trouble getting the connection to work. I've read through a bunch of tutorials and threads here on Stack Exchange of similar problems, and I'm not sure what I'm doing wrong.
The server is called "SQLEXPRESS" using Windows authentication. I downloaded the JDBC driver found here: https://www.microsoft.com/en-us/download/details.aspx?displaylang=en&id=11774 installed it in NetBeans by going to "Services-Databases(right click)-New Connection-Add", but I also added it as a library in my project.
When I try this code, I get the exception that the TCP/IP connection failed either because the server isn't running or port 1433 is locked:
try{
String
URL="jdbc:sqlserver://sqlexpress:1433;DatabaseName=GreenhouseManagement";
Connection conn = DriverManager.getConnection(URL,"","");
System.out.println("connected");
}catch(Exception e){
System.out.println("Oops\n"+e);
}
What do I need to change to fix this?
You might need to reconfigure your connection string into this format.
jdbc:microsoft:sqlserver://HOST:1433;DatabaseName=DATABASE
HOST in this case is most likely to be "localhost" since you are connecting on a local machine.
DATABASE will be the name of your database
Reference: http://alvinalexander.com/java/jdbc-connection-string-mysql-postgresql-sqlserver
I am new to Oracle, and am trying to run a simple example code with Java, but am getting this error when executing the code.. I am able to start up the listener via CMD and am also able to run SQL Plus. Can anyone give me a hand and tell me what I might be doing wrong?
Update:
I am using JDBC.
Database is local, and I actually had it working but it stopped working just today. I'm not really sure why though. Would you mind giving me some procedures to follow by since I don't know much.
Either:
The database isn't running
You got the URL wrong
There is a firewall in the way.
(This strange error message is produced by Oracle's JDBC driver when it can't connect to the database server. 'Network adapter' appears to refer to some component of their code, which isn't very useful. Real network adapters (NICs) don't establish connections at all: TCP protocol stacks do that. It would have been a lot more useful if they had just let the original ConnectException be thrown, or at least used its error message and let it appear in the stack trace.)
I had the same problem, and this is how I fixed it.
I was using the wrong port for my connection.
private final String DB_URL = "jdbc:oracle:thin:#localhost:1521:orcll"; // 1521 my wrong port
go to your localhost
(my localhost address) : https://localhost:1158/em
login
user name
password
connect as --> normal
Below 'General' click on LISTENER_localhost
look at you port number
Net Address (ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1522))
Connect to port 1522
Edit you connection
change port 1521 to 1522.
done
Another thing you might want to check that the listener.ora file matches the way you are trying to connect to the DB. If you were connecting via a localhost reference and your listener.ora file got changed from:
HOST = localhost
to
HOST = 192.168.XX.XX
then this can cause the error that you had unless you update your hosts file to accommodate for this. Someone might have made this change to allow for remote connections to the DB from other machines.
I figured out that in my case, my database was in different subnet than the subnet from where i was trying to access the db.
I had this error when i renamed the pc in the windows-properties. The pc-name must be updated in the listener.ora-file
Most probably you have listener configured wrongly, the hostname you specify in connection string must be the same as in the listener.
First check the Firewall and network related issues.
Check if Oracle Listener service is available and running. If not you may use Oracle Net Configuration Assistant tool to add and register new listener.
If the above steps are ok then you need to configure Oracle Listener appropriately. You may use Oracle Net Manager tool or edit “%ORACLE_HOME%\network\admin\listener.ora” file manually.
There are 2 options that need to be considered carefully:
Listening Locations associated with the Listener – Hostname(IP) and Port in Listening Location must exactly match the ones used in the connection string.
For example, if you use 192.168.74.139 as target hostname, then there must be Listening Location registered with the same IP address.
Also make sure the you use the same SID as indicated in Database Service associated with the Listener.
https://adhoctuts.com/fix-oracle-io-error-the-network-adapter-could-not-establish-the-connection-error/
IO Error: The Network Adapter could not establish the connection (CONNECTION_ID=iKQM6lBbSLiArrYuDqud8A==)
if you are facing this issue
1- make sure you have downloaded oracle databases like oracle 11g,19c, 21c, or any latest databases.
2- search for services in your computer or type win+r then services.mis then search for oracleservice you will find orcl or xe or any other sid like oracleserviceorcl;
after that you can test your connection using sql developer, sql plus or cmd
To resolve the Network Adapter Error I had to remove the - in the name of the computer name.
In my case, I needed to specify a viahost and viauser. Worth trying if you're in a complex system. :)
For me the basic oracle only was not installed. Please ensure you have oracle installed and then try checking host and port.
I was having issues with this as well. I was using the jdbc connection string to connect to the database. The hostname was incorrectly configured in the string. I am using Mac, and the same string was being used on Windows machines without an issue. On my connection string, I had to make sure that I had the full url with the appending "organizationname.com" to the end of the hostname.
Hope this helps.
Just try to re-create connection. In my situation one of jdbc connection stopped working for no reason. From console sqlplus was working ok.
It took me 2 hours to realize that If i create the same connection - it works.
I have build an application in java, application is one and will be used on 3 different systems,And therefore the database of that application must be online to keep all 3 applications with up to date database...
In starting I developed my application based on localhost (wampserver) and used database in "PhpMyAdmin", and hopefully application is fully developed and ready to run.. but the problem is online database connectivity!
I have uploaded my database on a Site in PhpMyAdmin and they provided below information:
and the for connecting my app to this DB is:
String url = "jdbc:mysql://fdb12.biz.nf:3306/";
String dbName = "1738412_wstore";
String driver = "com.mysql.jdbc.Driver";
String userName = "1738412_wstore";
String password = "Password";
Class.forName(driver).newInstance();
Connection conn = DriverManager.getConnection(url+dbName,userName,password);
now when I run my application it shows below error:
I dont know what the problem is there, please help me out through this..
I faced the same issue and the following helped me to solve.
http://support.hostgator.com/articles/cpanel/how-to-connect-to-the-mysql-database-remotely
Hopefully, your hosting provider should have same type of cpanel to configure MySQL database for remote connections.
Check for firewall.
Check if mysql is running.
2 things you can try:
Install MySql client locally on your machine and connect like: mysql -h fdb12.biz.nf -u 1738412_wstore -P<password>
This should work before you try anything else.
Make sure you're using the right imports in your code. See [here][1].
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
I think your DB server doesn't allow remote connections.
Try hosting in:
http://www.freesqldatabase.com/freemysqldatabase/
It's free and allow remote DB connections.
Good Luck!!!
Considering the Biz.nf FAQ:
How can I connect to my MySQL/PostgreSQL database? What settings
should I use for my script/software?
MySQL/PosgreSQL database connection can be established with script/software hosted only on your
web hosting account (meaning no remote access is allowed due to
security reasons). The following settings are needed:
So, since biz.nf does not allow remote access, it will be difficult for you to interact with their MYSQL server for your application.
The best solution and the most simple is probably to find a new provider which will allow the remote access. Heroku.com works very well.
If you really want to use the biz.nf services, it will be more difficult.
It's not a script or credential problem.
Maybe you can (probably not), try to login by SSH to configure your server to enable remote access to your MYSQL database server.
From the free plan, you will not have any access to the online SSH tool and you will need to configure your domain for a SSH connection.
In SSH, and it probably will not work considering the FAQ, you could try to simply modify your /etc/mysql/my.cnf file by commenting the bind-address line wich by default only allows local access (127.0.0.1). Then, try to restart your MYSQL service with: a simple service mysql restart to verify if the remote connection works.
If the remote connection still doesn't work after this, the only way I can find for the moment (unless you completely change your hosting provider) would be to create a kind of API hosted directly on the server and your Java program could interacts with your services (In JSON, by example).
When trying to connect with a remote Oracle database via JDBC I receive the following exception:
java.sql.SQLRecoverableException: IO-fout: The Network Adapter could not establish the connection
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:419)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:536)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:228)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:521)
at java.sql.DriverManager.getConnection(DriverManager.java:322)
at java.sql.DriverManager.getConnection(DriverManager.java:358)
The following is my set-up:
Database: Oracle 10g Release 2 Standard Edition
JDBC library: ojdbc6.jar
JDBC driver: oracle.jdbc.driver.OracleDriver
JDBC URL: jdbc:oracle:thin:#9.2.2.2:1521:ORCL where ORCL is database's SID
JDBC User/pwd: Correct username / password
Strange about this problem is that the connection works just fine when I work from work. When I try to connect however from home via an AT&T VPN connection, it doesn't work.
I have confirmed that I can reach the IP address and have also telnetted the ip on port 1521, which works just fine. Connecting to the datasource from a local WebLogic Application Server also works alright. Furthermore, when trying to connect to the database via sqldeveloper I can also reach the database.
I need to reach the database however from a standalone application (for testing purposes). Does anyone have an idea why this problem occurs? And whether there are alternatives for connecting to a remote Oracle Database, alternatives which sqldeveloper and weblogic perhaps use?
Here's an excerpt of the code attempting to connect with the database:
public static void main(String args[]) throws ClassNotFoundException, SQLException {
Class.forName("oracle.jdbc.driver.OracleDriver");
Connection conn = DriverManager.getConnection("jdbc:oracle:thin:#9.2.2.2:1521:ORCL", "user", "pwd");
}
When a client connects to an Oracle server, it first connnects to the Oracle listener service. It often redirects the client to another port. So the client has to open another connection on a different port, which is blocked by the firewall.
So you might in fact have encountered a firewall problem due to Oracle port redirection. It should be possible to diagnose it with a network monitor on the client machine or with the firewall management software on the firewall.
If it is on a Linux box, I would suggest you add the database IP name and IP resolution to the /etc/hosts.
I have the same error and when we do the above, it works fine.
Take a look at this post on Java Ranch:
http://www.coderanch.com/t/300287/JDBC/java/Io-Exception-Network-Adapter-could
"The solution for my "Io exception: The Network Adapter could not establish the connection" exception was to replace the IP of the database server to the DNS name."
I had similar problem before. But this was resolved when I started using hostname instead of IP address in my connection string.