I’m having the following problem:
When I try to createTcpServer with my external IP address (the PC’s IP and not my local IP = the one we see as an output after running ipconfig in cmd.exe) the following error occurs:
Error with Server: Exception opening port “9092” (port may be in use), cause: “java.net.BindException: Cannot assign requested address: JVM_Bind” [90061-169]
However, the port is not in use. I’ve checked that using netstat -a -n .
I have enabled my external IP and I have disabled the firewall from the router. My external IP can now be pinged.
Please help me.
Update: Here is my code to start the tcp server.
package businessApp;
import org.h2.tools.Server; //imports the server utility
public class startTcpServerForH2 {
Server server; //the server's instance variable
private static final String SERVER_IP = "192.168.1.101"; //fixed IP of the server
private static final String SERVER_PORT = "9092"; //fixed port the server is listening to
public void tcpServer() { //method responsible to create the tcp server
optionPane optPane = new optionPane(); //option pane for debugging purposes, shows the server's status
try { //catches any server related errors, if the connection is broken etc.
//server uses the IP and port defined earlier, allows other computers in the LAN to connect and implements the secure socket layer (SSL) feature
server = Server.createTcpServer( //create tcp server
new String[] { "-tcpPort" , SERVER_PORT , "-tcpAllowOthers" , "-tcpSSL" }).start();
System.out.println(server.getStatus()); //prints out the server's status
optPane.checkServerStatus(server.getStatus()); //prints out the server's status on the option pane as well
} catch(Exception ex){
System.out.println("Error with Server: " + ex.getMessage());
}
}
public static void main(String[] args){
startTcpServerForH2 tcpServ = new startTcpServerForH2(); //create a new server object
tcpServ.tcpServer(); //starts the tcp server
}
}
Second Update: here is the h2Connection code.
package businessApp;
import java.sql.*; //imports sql features
//Class responsible for connection with H2 Database Engine
public class h2Connection {
Connection conn; //connection variable
DatabaseMetaData dbmd; /** Metadata variable which include methods such as the following:
* 1) Database Product Name
* 2) Database Product Version
* 3) URL where the database files are located (in TCP mode)
*/
Statement stm; //statements variable
ResultSet rst; //result sets variable
private static final String SERVER_IP = "..."; //here I enter my WAN_IP
private static final String SERVER_PORT = "9092";
public Connection connectionToH2(Connection connt) {
optionPane optPane = new optionPane(); //create new option pane object
String outputConn = null; //declare & initialize string which will hold important messages
try {
Class.forName("org.h2.Driver"); //Driver's name
/** The String URL is pertained of the following:
* 1) jdbc which java implements so that it can take advantage of the SQL features
* 2) Which Database Engine will be used
* 3) URL where the files will be stored (as this is a TCP connection)
* 4) Schema: businessApp
* 5) Auto server is true means that other computers can connect with the same databse at any time
* 6) Port number of the server is also defined
*/
String url = "jdbc:h2:tcp://" + SERVER_IP + ":" + SERVER_PORT + "/C:/Databases/businessApp;IFEXISTS=TRUE";
System.out.println(url); //prints out the url the database files are located as well as the h2 features used (SSL)
connt = DriverManager.getConnection(url, "sa", ""); //Driver Manager defines the username & password of the database
System.out.println(connt.getCatalog()); //prints out the database schema
optPane.checkServerStatus(connt.getCatalog()); //prints out the database schema on the option pane as well
connt.setAutoCommit(false); //set AutoCommit to false to control commit actions manually
//outputs H2 version and the URL of the database files which H2 is reading from, for confirmation
dbmd = connt.getMetaData(); //get MetaData to confirm connection
outputConn = "Connection to "+dbmd.getDatabaseProductName()+" "+
dbmd.getDatabaseProductVersion()+ " with the URL " + dbmd.getURL()+" was successful.\n";
System.out.println(outputConn); //outputs the message on the system (NetBeans compiler)
optPane.checkH2Connection(outputConn); //outputs the message on top of the frame
} catch (ClassNotFoundException ex){ //In case there is an error for creating the class for the Driver to be used
System.out.println("Error creating class: " + ex.getMessage());
} catch(SQLException ex){ //Any error associated with the Database Engine
System.out.println("SQL error: " + ex.getMessage());
optPane.checkServerStatus("SQL error: " + ex.getMessage());
}
return connt; //As the method is not void, a connection variable must be returned
}
}
When I want to connect to the h2 database, I make a new h2Connection object and use it to connect. I have followed the H2 manual word by word. What more do you need?
As suggested in the command line help shown below, Protection against Remote Access advises the following:
See the documentation for important caveats regarding these options.
Addendum: Works for me, as long as I restart the
Serverafter opening the firewall; you don’t need thesetProperty()line at all; theLAN IPto which yourWAN_IPforwards port 9092 should be your host IP address; then you can open a shell via yourWAN_IP:Command line help: