Elio Elio - 6 months ago 39
Java Question

Connect to Java DB server (Derby) from network

I have used the following code to start the Java DB server:

System.setProperty("derby.drda.startNetworkServer", "true");
try {
NetworkServerControl serverControl = new NetworkServerControl();
serverControl.start(new PrintWriter(System.out, true));
} catch (Exception e) {
e.printStackTrace();
}


I can connect to the database on the local PC using the URL:

String dbURLTable = "jdbc:derby://localhost:1527/Tables;create=true;user=Gen;password=YZG";


But when I try to connect to it on LAN (Firewall disabled) I use the following URL:

String dbURLTable = "jdbc:derby://192.168.1.105:1527/Tables;create=true;user=Gen;password=YZG";


Yet the other PC cannot connect to this database, what's the problem?
The error I'm getting is:

java.sql.SQLNonTransientConnectionException: java.net.ConnectException : Error connecting to server 192.168.1.106 on port 1,527 with message Connection refused: connect.
at org.apache.derby.client.am.SQLExceptionFactory.getSQLException(Unknown Source)
at org.apache.derby.client.am.SqlException.getSQLException(Unknown Source)
at org.apache.derby.jdbc.ClientDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:270)
at Admin.CreateTables.CreateT(CreateTables.java:188)
at Admin.CreateTables.run(CreateTables.java:13)
at java.lang.Thread.run(Thread.java:745)
Caused by: ERROR 08001: java.net.ConnectException : Error connecting to server 192.168.1.106 on port 1,527 with message Connection refused: connect.
at org.apache.derby.client.net.NetAgent.<init>(Unknown Source)
at org.apache.derby.client.net.NetConnection.newAgent_(Unknown Source)
at org.apache.derby.client.am.ClientConnection.<init>(Unknown Source)
at org.apache.derby.client.net.NetConnection.<init>(Unknown Source)
at org.apache.derby.client.net.ClientJDBCObjectFactoryImpl.newNetConnection(Unknown Source)
... 6 more
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:345)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at java.net.Socket.connect(Socket.java:538)
at java.net.Socket.<init>(Socket.java:434)
at java.net.Socket.<init>(Socket.java:211)
at javax.net.DefaultSocketFactory.createSocket(SocketFactory.java:271)
at org.apache.derby.client.net.OpenSocketAction.run(Unknown Source)
at org.apache.derby.client.net.OpenSocketAction.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
... 11 more

Answer

This is happening because you are creating NetworkServerControl by using 0-arg constructor NetworkServerControl() which does not allow remote connections

You have to use NetworkServerControl(InetAddress address, int portNumber) in order to allow remote connections

//accepts connections from other hosts on an IPv4 system
NetworkServerControl serverControl = 
  new NetworkServerControl(InetAddress.getByName("0.0.0.0"),1527);

For details please see this

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