java - Cannot connect to a remote PostgreSQL database through SSH using JDBC and JSCH

Question

I am trying to connect to the remote database using JDBC and JSCH. To achieve that, I am using this tutorial: Connect to Remote database Note that it provides the connection for MySQL, so I change driver name to:

Class.forName("org.postgresql.Driver");

and URL:

DriverManager.getConnection("jdbc:postgresql://localhost:"+nLocalPort + "/", strDbUser, strDbPassword);

But I do get this type of error:

Caused by: java.io.EOFException

Here is the full stack trace:

org.postgresql.util.PSQLException: The connection attempt failed.
    at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:292)
    at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
    at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:195)
    at org.postgresql.Driver.makeConnection(Driver.java:454)
    at org.postgresql.Driver.connect(Driver.java:256)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
    at SQL.main(SQL.java:42)
Caused by: java.io.EOFException
    at org.postgresql.core.PGStream.receiveChar(PGStream.java:308)
    at org.postgresql.core.v3.ConnectionFactoryImpl.enableSSL(ConnectionFactoryImpl.java:405)
    at org.postgresql.core.v3.ConnectionFactoryImpl.tryConnect(ConnectionFactoryImpl.java:94)
    at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:192)
    ... 7 more

With the same credentials I can connect to the database through IntelliJ. And Putty as well. But I can't make it with JDBC and JSCH. What am I doing wrong? I also read almost every question about this problem in the forum but I couldn't find the right solution.

The code itself from the link:

import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Properties;

import com.jcraft.jsch.JSch;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;

public class CTestDriver
{
private static void doSshTunnel( String strSshUser, String strSshPassword, String strSshHost, int nSshPort, String strRemoteHost, int nLocalPort, int nRemotePort ) throws JSchException
{
    final JSch jsch = new JSch();
    Session session = jsch.getSession( strSshUser, strSshHost, 22 );
    session.setPassword( strSshPassword );
 
    final Properties config = new Properties();
    config.put( "StrictHostKeyChecking", "no" );
    session.setConfig( config );
 
    session.connect();
    session.setPortForwardingL(nLocalPort, strRemoteHost, nRemotePort);
}

public static void main(String[] args)
{
    try
    {
    String strSshUser = "ssh_user_name";                  // SSH loging username
    String strSshPassword = "abcd1234";                   // SSH login password
    String strSshHost = "your.ssh.hostname.com";          // hostname or ip or SSH server
    int nSshPort = 22;                                    // remote SSH host port number
    String strRemoteHost = "your.database.hostname.com";  // hostname or ip of your database server
    int nLocalPort = 3366;                                // local port number use to bind SSH tunnel
    int nRemotePort = 3306;                               // remote port number of your database 
    String strDbUser = "db_user_name";                    // database loging username
    String strDbPassword = "4321dcba";                    // database login password
   
    CTestDriver.doSshTunnel(strSshUser, strSshPassword, strSshHost, nSshPort, strRemoteHost, nLocalPort, nRemotePort);
   
    Class.forName("org.postgresql.Driver");
    Connection con = DriverManager.getConnection("jdbc:postgresql://localhost:"+nLocalPort, strDbUser, strDbPassword);
    con.close();
    }
    catch( Exception e )
    {
    e.printStackTrace();
    }
    finally
    {
    System.exit(0);
    }
}
}

question from:https://stackoverflow.com/questions/65542102/cannot-connect-to-a-remote-postgresql-database-through-ssh-using-jdbc-and-jsch

Answer 1

Waitting for answers