Another challenge bashed my head these days. I am trying to create a FTP Server in Java which should be able to communicate with the FileZilla FTP Client. The code isn't the best because i tried a lot of things to find out what is going on.
Here the FileZilla log translated from german
Status: Connect to 127.0.0.1:21...
Status: Connected!Waiting for welcome message.
Response: 220 localhost connected
Error: Establishing connection to server failed.
The main problem so far is to establish the real connection. The sockets are connected and i can send at least one message to the client back but have no chance to get the clients input e.g. for PASV, USER and PASS.
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import javax.swing.JButton;
import javax.swing.JFrame;
public class FTP_Server extends JFrame implements ActionListener, WindowListener {
private static final long serialVersionUID = 1L;
private Container cp;
private JButton btncon;
private ServerSocket listenSocket;
private Socket connectionSocket;
private DataOutputStream dos;
private DataInputStream dis;
private OutputStream os;
private InputStream is;
public FTP_Server() {
super("FTP Server");
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
cp = this.getContentPane();
cp.setLayout(new BorderLayout());
btncon = new JButton("Connect");
btncon.addActionListener(this);
cp.add(btncon, BorderLayout.CENTER);
this.pack();
this.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent e) {
if(e.getSource().equals(btncon)){
createConnection();
}
}
public void createConnection() {
System.out.println("Connecting...");
try {
listenSocket = new ServerSocket(21);
listenSocket.setSoTimeout(0);
connectionSocket = listenSocket.accept();
connectionSocket.setSoLinger(true, 0);
connectionSocket.setSoTimeout(0);
connectionSocket.setKeepAlive(true);
System.out.println("Connected!");
os = connectionSocket.getOutputStream();
dos = new DataOutputStream(os);
is = connectionSocket.getInputStream();
dis = new DataInputStream(is);
while(connectionSocket.isConnected() == true) {
dos.writeUTF("220 localhost connected\r\n");
//Will cause socket write error soon!
dos.flush();
dos.writeUTF("331 Anonym no password needed\r\n");
System.out.println(is.read());
}
} catch (SocketException exp) {
try {
listenSocket.close();
System.out.println("Disconnected");
exp.printStackTrace();
} catch (IOException exp2) {
exp2.printStackTrace();
}
} catch (IOException exp) {
exp.printStackTrace();
}
}
@Override
public void windowOpened(WindowEvent e) {
// TODO Auto-generated method stub
}
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
@Override
public void windowClosed(WindowEvent e) {
// TODO Auto-generated method stub
}
@Override
public void windowIconified(WindowEvent e) {
// TODO Auto-generated method stub
}
@Override
public void windowDeiconified(WindowEvent e) {
// TODO Auto-generated method stub
}
@Override
public void windowActivated(WindowEvent e) {
// TODO Auto-generated method stub
}
@Override
public void windowDeactivated(WindowEvent e) {
// TODO Auto-generated method stub
}
}
For the error message/print stack:
java.net.SocketException: Software caused connection abort: socket write error
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:109)
at java.net.SocketOutputStream.write(SocketOutputStream.java:153)
at java.io.DataOutputStream.write(DataOutputStream.java:107)
at java.io.DataOutputStream.writeUTF(DataOutputStream.java:401)
at java.io.DataOutputStream.writeUTF(DataOutputStream.java:323)
at ftp.FTP_Server.createConnection(FTP_Server.java:82)
at ftp.FTP_Server.actionPerformed(FTP_Server.java:58)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6505)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
at java.awt.Component.processEvent(Component.java:6270)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Component.dispatchEventImpl(Component.java:4861)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
at java.awt.Container.dispatchEventImpl(Container.java:2273)
at java.awt.Window.dispatchEventImpl(Window.java:2719)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:723)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:682)
at java.awt.EventQueue$3.run(EventQueue.java:680)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:696)
at java.awt.EventQueue$4.run(EventQueue.java:694)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:693)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)
I still have trouble with the messaging. What i now did was to create a new thread for every connected socket as well as for every now outputstream.
package ftp;
import java.io.DataOutputStream;
import java.io.IOException;
public class MultiIO implements Runnable{
private DataOutputStream dos;
public MultiIO(DataOutputStream stream) {
dos = stream;
System.out.println("Set OutputStream.");
}
@Override
public void run() {
try {
dos.writeBytes("220");
dos.flush();
System.out.println("tried once");
} catch (IOException e) {
System.exit(-1);
}
}
}
The trouble now is that the FileZilla client won't get the 220 message.
here is the new socket handling class. i kinda copied it from the oracle page.
package ftp;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;
import java.net.SocketException;
public class MultiConnection implements Runnable{
private Socket cSocket;
public MultiConnection(Socket client) {
cSocket = client;
System.out.println("Connected!");
}
@Override
public void run() {
OutputStream os = null;
DataOutputStream dos = null;
try {
os = cSocket.getOutputStream();
dos = new DataOutputStream(os);
} catch (SocketException es) {
es.printStackTrace();
} catch (IOException e) {
System.exit(-1);
}
MultiIO mio;
mio = new MultiIO(dos);
Thread thio = new Thread(mio);
thio.start();
}
}