Problem in socket...

Hi,
I'm doing a load balancing program now. Actually, i want to send the client request from load balancer to other server. For example, when a user makes a request to the load balancer (i'm using tomcat), the load balancer will get the load info from each server. After that, it will redirect the request to the selected server for fullfilling it. The problem is : how can the load balancer send the request to the selected server? I realise that it's impossible to send the Socket to other server coz it's not Serializable. So, is there any one got the idea to solve this problem? Help me please...Your help is appreciated...
thanks,
Nicholas Tham

the architecher that i imagined is Browser->Your load balnce server (port must be 80) -> Your Web Server
you want to redirect from the client browser or your program? if you want the browser to redirect just contact me [email protected]
if not, connect the web server from your load balance server. but your load balance server must detect your web server whether is it busy or not. if you server was busy, go to another server. so you need to put your server list as an array in your server.

Similar Messages

I suppose it is the problem with socket connection,Please help

Hi,
I'm trying to build a chat server in Java on Linux OS.I've created basically 2 classes in the client program.The first one shows the login window.When we enter the Login ID & password & click on the ok button,the data is sent to the server for verification.If the login is true,the second class is invoked,which displays the messenger window.This class again access the server
for collecting the IDs of the online persons.But this statement which reads from the server causes an exception in the program.If we invoke the second class independently(ie not from 1st class) then there is no problem & the required data is read from the server.Can anyone please help me in getting this program right.I'm working on a p4 machine with JDK1.4.
The Exceptions caused are given below
java.net.SocketException: Connection reset by peer: Connection reset by peer
at java.net.SocketInputStream.SocketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:119)
     at java.io.InputStreamReader$CharsetFiller.readBytes(InputStreanReader.java :339)
     at java.io.InputStreamReader$CharsetFiller.fill(InputStreamReader.java:374)
     at java.io.InputStreamReader.read(InputStreamReader.java:511)
     at java.io.BufferedReader.fill(BufferedReader.java:139)
     at java.io.BufferedReader.readLine(BufferedReader.java:299)
     at java.io.BufferedReader.readLine(BufferedReader.java:362)
     at Login.LoginData(Login.java:330)
     at Login.test(Login.java:155)
     at Login$Buttonhandler.actionPerformed(Login.java:138)
     at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1722)
     at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:17775)
     at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:4141)
     at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:253)
     at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:261)
     at java.awt.Component.processMouseEvent(Component.java:4906)
     at java.awt.Component.processEvent(component.java:4732)
     at java.awt.Container.processEvent(Container.java:1337)
     at java.awt.component.dispatchEventImpl(Component.java:3476)
     at java.awt.Container.dispatchEventImpl(Container.java:1399)
     at java.awt.Component.dispatchEvent(Component.java:3343)
     at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3302)
     at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3014)
     at java.awt.LightweightDispatcher.dispatchEvent(Container.java:2967)
     at java.awt.Container.dispatchEventImpl(Container.java:1373)
     at java.awt.window.dispatchEventImpl(Window.java:1459)
     at java.awt.Component.dispatchEvent(Component.java:3343)
     at java.awt.EventQueue.dispatchEvent(EventQueue.java:439)
     at java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java:150)
     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:136)
     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:131)
     at java.awt.EventDispatchThread.run(EventDispatchThread.java:99)
     My program looks somewhat like this :
1st class definition:
public class Login extends Jframe// Login is the name of the first class;
Socket connection;
DataOutputStream outStream;
BufferedReader inStream;
Frame is set up here
public class Buttonhandler implements ActionListener
public void actionPerformed(ActionEvent e) {
String comm = e.getActionCommand();
if(comm.equals("ok")) {
check=LoginCheck(ID,paswd);
test();
public void test() //checks whether the login is true
if(check)
new Messenger(ID);// the second class is invoked
public boolean LoginCheck(String user,String passwd)
//Enter the Server's IP & port below
String destination="localhost";
int port=1234;
try
connection=new Socket(destination,port);
}catch (UnknownHostException ex){
error("Unknown host");
catch (IOException ex){
ex.printStackTrace ();
error("IO error creating socket ");
try{
inStream = new BufferedReader(new InputStreamReader(connection.getInputStream()));
outStream=new DataOutputStream(connection.getOutputStream());
}catch (IOException ex){
error("IO error getting streams");
ex.printStackTrace();
System.out.println("connected to "+destination+" at port "+port+".");
BufferedReader keyboardInput=new BufferedReader(new InputStreamReader(System.in));
String receive=new String();
try{
receive=inStream.readLine();
}catch(IOException ex){ error("Error reading from server");}
if(receive.equals("Logintrue"))
check=true;
else
check=false;
try{
inStream.close();
outStream.close();
connection.close();
}catch (IOException ex){
error("IO error closing socket");
return(check);
// second class is defined below
public class Messenger
Socket connect;
DataOutputStream outStr;
BufferedReader inStr;
public static void main(String args[])
{ Messenger mes = new Messenger(args[0]);}
Messenger(String strg)
CreateWindow();
setupEvents();
LoginData(strg);
fram.show();
void setupEvents()
fram.addWindowListener(new WindowHandler());
login.addActionListener(new MenuItemHandler());
quit.addActionListener(new MenuItemHandler());
button.addActionListener(new Buttonhandle());
public void LoginData(String name)
//Enter the Server's IP & port below
String dest="localhost";
int port=1234;
int r=0;
String str[]=new String[40];
try
connect=new Socket(dest,port);
}catch (UnknownHostException ex){
error("Unknown host");
catch (IOException ex){
ex.printStackTrace ();
error("IO error creating socket ");
try{
inStr = new BufferedReader(new InputStreamReader(connect.getInputStream()));
outStr=new DataOutputStream(connect.getOutputStream());
}catch (IOException ex){
error("IO error getting streams");
ex.printStackTrace();
String codeln=new String("\n");
try{
outStr.flush();
outStr.writeBytes("!@*&!@#$%^");//code for sending logged in users
outStr.writeBytes(codeln);
outStr.write(13);
outStr.flush();
String check="qkpltx";
String receive=new String();
try{
while((receive=inStr.readLine())!=null) //the statement that causes the exception
if(receive.equals(check))
break;
else
     str[r]=receive;
     r++;
}catch(IOException ex){ex.printStackTrace();error("Error reading from socket");}
catch(NullPointerException ex){ex.printStackTrace();}
} catch (IOException ex){ex.printStackTrace();
error("Error reading from keyboard or socket ");
try{
inStr.close();
outStr.close();
connect.close();
}catch (IOException ex){
error("IO error closing socket");
for(int l=0,k=1;l<r;l=l+2,k++)
if(!(str[l].equals(name)))
stud[k]=" "+str[l];
else
k--;
public class Buttonhandle implements ActionListener
public void actionPerformed(ActionEvent e) {
//chat with the selected user;
public class MenuItemHandler implements ActionListener
public void actionPerformed(ActionEvent e)
String cmd=e.getActionCommand();
if(cmd.equals("Disconnect"))
//Disconnect from the server
else if(cmd.equals("Change User"))
     //Disconnect from the server & call the login window
else if(cmd.equals("View Connection Details"))
//show connection details;
public class WindowHandler extends WindowAdapter
public void windowClosing(WindowEvent e){
//Disconnect from server & then exit;
System.exit(0);}
I�ll be very thankful if anyone corrects the mistake for me.Please help.

You're connecting to the server twice. After you've successfully logged in, pass the Socket to the Messenger class.
public class Messenger {
    Socket connect;
    public static void main(String args[]) {
        Messenger mes = new Messenger(args[0]);
    Messenger(Socket s, String strg) {
        this.connect = s;
        CreateWindow();
        setupEvents();
        LoginData(strg);
        fram.show();
}

Problem with socket connection

have my gps reciver connected to the usb port - i have a daemon gpsd running which makes data available on tcp port 2947 for querying. when i do telnet, it gives proper data.
but when i open a socket connection using java, it does not print anything as output. actually telnet asks for an escape charatcer so i am sending "r" initially to the server but still the program does not print anything as output.
here is my java code -
import java.io.*;
import java.net.Socket;
public class test2
public static void main(String[] args)
try
Socket s = new Socket("localhost",2947);
PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
s.getOutputStream())),true);
out.println("r");
BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));
String line;
while(true)
line = in.readLine();
System.out.println(line);
catch (Exception e)
or sometimes it even shows error as
Exception in thread "main" java.net.SocketException: Invalid argument or cannot assign requested address
at java.net.PlainSocketImpl.socketConnect(Native Method)
and this is the output which i get on telnet -
ot@localhost ~]# telnet localhost 2947
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
r
GPSD,R=1
$GPRMC,000212,V,18000.0000,N,00000.0000,W,0.0000,180.000,101102,,*1A
$GPGSA,A,1,,,,,,,,,,,,,,,,*32
$PGRME,400.00,0.00,0.00*7B
$GPRMC,000213,V,18000.0000,N,00000.0000,W,0.0000,180.000,101102,,*1B
$GPGSA,A,1,,,,,,,,,,,,,,,,*32
$PGRME,400.00,0.00,0.00*7B
$GPRMC,000214,V,18000.0000,N,00000.0000,W,0.0000,180.000,101102,,*1C
$GPGSA,A,1,,,,,,,,,,,,,,,,*32

Actually the problem does not seem to be in the code because i tried some basic client server programs (without any gpsd etc in picture) and even they are not working in linux though they work perfectly in windows (on the same machine). In linux it shows exception
My socket programs dont work in linux it shows error -
ot@localhost winc]# java parser
Exception in thread "main" java.net.SocketException: Invalid argument or cannot assign requested address
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:305)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:171)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:158)
at java.net.Socket.connect(Socket.java:452)
at java.net.Socket.connect(Socket.java:402)
at java.net.Socket.<init>(Socket.java:309)
at java.net.Socket.<init>(Socket.java:124)
at parser.main(parser.java:10)
i have removed the firewall settings etc and it still doesnot work in linux
what could be the cause for this?
Sowmya

Problem with socket responses with flex

Hi, I am using the code below to connect to an IMAP server.
When I telnet to the server and use the commands that I am sending in the code, the rsponses are correct.
However, when I run the code below, I only obtain the ready and logged in responses as shown below.
Any ideas why I am not receiving the full set of responses from the socket?
Thanks in advance fro your advice.
The following is the output from the code:
+++++++++++++++++ START SENDING IMAP DATA +++++++++++++++++++++++++
sent: . login user1 myPassword
sent: . status INBOX (messages)
sent: . select INBOX
+++++++++++++++++ END SENDING IMAP DATA +++++++++++++++++++++++++
++++++++ [IMAP START]
Response is: * OK Dovecot ready.
[IMAP END] +++++++++
++++++++ [IMAP START]
Response is: . OK Logged in.
[IMAP END] +++++++++
The code is:
<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
   xmlns:s="library://ns.adobe.com/flex/spark"
   xmlns:mx="library://ns.adobe.com/flex/mx"
   applicationComplete="init()">
<fx:Declarations>

</fx:Declarations>
<fx:Script>
<![CDATA[
public var dataStr:String;
private var socket:Socket;
private var serverURL:String= "dead.org";
private var serverPort:int = 143;
private var serverResponse:ByteArray = new ByteArray();
private function init():void
this.serverURL = serverURL;
this.serverPort = serverPort;
socket = new Socket();
socket.addEventListener(ProgressEvent.SOCKET_DATA,handleNewIMAPData); //Event when socket receives new data
this.connectToServer();
sendIMAPdata();
private function sendString(dataStr:String):void
var bytes:ByteArray = new ByteArray();
bytes.writeMultiByte(dataStr, "UTF-8");
socket.writeBytes(bytes);
socket.flush();
trace("sent: " + dataStr);
public function sendIMAPdata():void
trace("\t +++++++++++++++++ START SENDING IMAP DATA +++++++++++++++++++++++++");
dataStr =". login user1 myPassword" + "\r\n";
sendString(dataStr);
dataStr =". status INBOX (messages)" + "\r\n";
sendString(dataStr);
dataStr =". select INBOX" + "\r\n";
      sendString(dataStr);
trace("\t +++++++++++++++++ END SENDING IMAP DATA +++++++++++++++++++++++++");
private function handleNewIMAPData(event:ProgressEvent):void
var numBytes:int = socket.bytesAvailable;
serverResponse = new ByteArray();
while(socket.bytesAvailable)
    var byte:int = socket.readUnsignedByte();
serverResponse.writeByte(byte);
var response:String = serverResponse.toString();
trace(" ++++++++ [IMAP START]\n Response is: " + response + "[IMAP END] +++++++++\n");
private function connectToServer():void
socket.connect(serverURL, serverPort);
]]>
</fx:Script>
</s:WindowedApplication>

When I run telnet, the console responses are the same as the tcpdump messages.
When I run the program, the messages from tcpdump match the messages in my trace statements.
The messages from telnet and running the program are different:-)
I can only assume (at the moment) that I am sending multiple messages too quickly(?), but I did a quick and dirty big "for loop" to slow down the sending of subsequent messages, but with no resulting change in the programs behaviour.
So, still thinking about the problem - unfortunately.

Problem with Socket in FireFox 3.5

My applet is trying to open a SecureSocket in FF 3.5 to connect to port xxxx on the server. Everything works fine for IE and FF below 3.5. However, in FF 3.5, I find out that everytime I open a Socket, it opens 2 ports to connect to port xxxx on the server. For IE and FF below 3.5, it only opens 1 port to connect to port xxxx on the server. I don't know what is the problem here. Is this a bug of FF? Is there anyway to work around this because my server only accepts one connection from each client.If the client is trying to connect to it more than one, it will refuse.

Kirax wrote:
Is this a bug of FF? Seems unlikely that it would be a FF bug, as all of that code is (to my knowledge) run strictly within a JVM. Can you post an SSCCE? Perhaps you have a bug that is only being exposed on a certain environment.
Is there anyway to work around this because my server only accepts one connection from each client.If the client is trying to connect to it more than one, it will refuse.What happens on your client if your server just refuses the second connection? Where's the harm?
Edited by: endasil on 3-Oct-2009 2:54 AM

Problem with socket programming(Vista)

I'm not sure if this has something to do with windows vista.
I wrote simple echo client and server programs and the client program contains these lines
String hostname="172.16.54.22"; //My comp's IP
int portNo=6666;
mySocket=new Socket(hostname, portNo);
Now the problem is that the client program is able to communicate with the server only when I run both of them in xp machines or if I run the server in vista and client in xp. The client is not able to connect to the server when both the client and server are running in a vista machine or if the server is running in xp and client in vista.
It'd be nice if any of you could throw some light on this issue.
PS:
It doesn't work even if I turn the firewall off
The programs work well when I give hostname="localhost" or hostname="127.0.0.1"
Here are my programs
//EchoClient.java
import java.io.*;
import java.net.*;
import java.util.*;
class EchoClient
     public static void main(String args[])
          String hostname="172.16.54.25"; //My ip address
          int portNo=6666;
          //if(args[1]
          //PrintWriter out=null;
          Socket mySocket=null;
          BufferedReader networkIn=null;
          BufferedReader userIn=null;
          PrintWriter sockOut=null;
          try
               mySocket=new Socket(hostname, portNo);
               networkIn=new BufferedReader(new InputStreamReader(mySocket.getInputStream()));
               userIn=new BufferedReader(new InputStreamReader(System.in));
               sockOut= new PrintWriter(mySocket.getOutputStream());
               System.out.println("Connected to Echo Server\n");
               System.out.println("Enter a series of lines (\"end\" to exit)\n");
               while(true)
                    String myLine=userIn.readLine();
               //     System.out.println(myLine);
                    if(myLine.equals("end"))
                         break;
                    sockOut.println(myLine);
                    sockOut.flush();
                    System.out.println(networkIn.readLine());
          catch(IOException exc)
               System.err.println(exc);
          finally
               try{
               if(networkIn!=null) networkIn.close();
               if(sockOut!=null) sockOut.close();}
               catch(IOException exc){ }
               EchoServer.java
//EchoServer.java
import java.io.*;
import java.net.*;
class EchoServer
     public static void main(String args[])
          int portNo=6666;
          ServerSocket serverSock=null;
          try
               serverSock=new ServerSocket(portNo);
               System.out.println("Echo Server Started\n\n");
               while(true)
                    Socket clientSock=serverSock.accept();
                    new Thread(new EchoServerThread(clientSock)).start();
          catch(IOException exc)
               System.err.println(exc);
     EchoServerThread.java
//EchoServerThread.java
import java.io.*;
import java.net.*;
import java.util.*;
public class EchoServerThread implements Runnable
     public Socket clientSock;
     EchoServerThread(Socket sock)
          clientSock=sock;
     public void run()
          System.out.println("\nAccepted Connection from a Client");
          try{
          BufferedReader in=new BufferedReader(new InputStreamReader(clientSock.getInputStream()));
          BufferedReader userIn=new BufferedReader(new InputStreamReader(System.in));
          PrintWriter out= new PrintWriter(clientSock.getOutputStream());
                    /*In sockIn=new In(clientSock);
          Out sockOut=new Out(clientSock);*/
          String str;
          while((str=in.readLine())!=null)
               out.println(str);
               out.flush();
          System.out.println("Closing Connection from a Client");
          out.close();
          in.close();
          catch(IOException exc)
               System.err.println(exc);


Sorry everyone but I'd been giving a wong IP address thinking it's my own. The problem's solved.
Thanks for the response Peter.

Problem with Socket Client - Intermittent Truncated Response in AIX

{color:#0000ff}Hi guru
I have written on Socket Client method below to send request byte[] to Host and receive response byte[] from Host.
For this particular response, I'm expecting Host to return me byte[] with length 2274.
My problem is intermittently I received truncated message byte[] from Host with length only 1392. Sometimes I received full 2274 message, sometimes I received 1392 length. I tested in continual of 10 times by sending the same request to host, intermittently received truncated response message.
My real problem is that this only happened in {color:#ff0000}AIX {color}machine. With the same class, I tested on {color:#ff0000}Windows {color}platform and i received full response message byte[] with 2274 lenght always. Therefore, im counting out the possibilities that Host might send me truncated message.
Can anyone pls help to tell me how should I proceed to troubleshoot this problem in AIX? Is possible for me to trace what coming in?
{color}
public byte[] sendToHost(byte[] requestMessage, String requestId, String localTxnCode) throws Exception {
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
long startTime = 0;
long elapsed = 0;
try {
LogManager.log(LogManager.DEBUG, Constants.DEFAULT_LOGGER_NAME, requestId, "[" + localTxnCode + "] To connect and send message to Host hostAddr=[" + hostAddr + "], hostPort=[" + hostPort
+ "]");
startTime = System.currentTimeMillis();
hostSocket = new Socket(InetAddress.getByName(hostAddr), hostPort);
hostSocket.setSoTimeout(timeOut);
byte responseData[] = new byte[4096];
bis = new BufferedInputStream(hostSocket.getInputStream());
bos = new BufferedOutputStream(hostSocket.getOutputStream());
bos.write(requestMessage);
bos.flush();
int length = bis.read(responseData);
elapsed = System.currentTimeMillis() - startTime;
ARBAdapterUtil.log(LogManager.DEBUG, Constants.DEFAULT_LOGGER_NAME, requestId, "[" + localTxnCode + "] Received message from Host length=[" + length + "]");
// The response byte must not be 4096 everytime
byte[] returnByte = new byte[length];
for (int i = 0; i < length; i++) {
returnByte[i] = responseData;
return returnByte;
} catch (BindException b) {
elapsed = System.currentTimeMillis() - startTime;
throw new SocketException("Socket Exception: BindException IP=" + hostAddr + " PORT=" + hostPort + " Error type=" + b.getClass().getName() + " Error message=" + b.getMessage());
} catch (ConnectException c) {
elapsed = System.currentTimeMillis() - startTime;
throw new SocketException("Socket Exception: ConnectException IP=" + hostAddr + " PORT=" + hostPort + " Error type=" + c.getClass().getName() + " Error message=" + c.getMessage());
} catch (NoRouteToHostException nrth) {
elapsed = System.currentTimeMillis() - startTime;
throw new SocketException("Socket Exception: NoRouteToHostException IP=" + hostAddr + " PORT=" + hostPort + " Error type=" + nrth.getClass().getName() + " Error message="+ nrth.getMessage());
} catch (SocketTimeoutException se) {
elapsed = System.currentTimeMillis() - startTime;
throw new SocketTimeoutException("Socket Exception: SocketTimeoutException IP=" + hostAddr + " PORT=" + hostPort + " Error type=" + se.getClass().getName() + " Error message=" + se.getMessage());
} catch (SocketException s) {
elapsed = System.currentTimeMillis() - startTime;
throw new SocketException("Socket Exception: SocketException IP=" + hostAddr + " PORT=" + hostPort + " Error type=" + s.getClass().getName() + " Error message=" + s.getMessage());
} catch (Exception e) {
elapsed = System.currentTimeMillis() - startTime;
throw new Exception("Unknown Exception: Exception IP=" + hostAddr + " PORT=" + hostPort + "Error type=" + e.getClass().getName() + " Error message=" + e.getMessage());
} finally {
try {
ARBAdapterUtil.log(LogManager.INFO, Constants.DEFAULT_LOGGER_NAME, requestId, "ARBConnection.sendToHost() [" + localTxnCode + "] Time Elapsed via Socket in millisecond = [" + elapsed + "]");
if (bis != null) {
bis.close();
bis = null;
if (bos != null) {
bos.close();
bos = null;
} catch (Exception e) {
LogManager.log(LogManager.ERROR, Constants.DEFAULT_LOGGER_NAME, requestId, "ARBConnection.sendToHost() [" + localTxnCode + "] Exception during closing BufferedInputStream and BufferedOutputStream");

I tried to use DataInputStream.readFully(byte[]). However, I could not retrieve a single byte from Host. It won't return until it fills the buffer, or EOS occurs. Isn't that what you wanted?
You need to believe it here. Either the sending application or Java or the sending TCP stack or the intervening routers or the receiving TCP stack or Java or the receiver can break up the transmission into 1 byte reads and there is nothing you can do about it at the receiver except what I said. BufferedInputStream will mask the effect to some extent but you still have to code under that assumption. You don't have any choice about this.

Problem with socket connection in midp 2.0

hello everyone.
I'm new one in j2me and I am learning socket connection in j2me. I'm using basic socket,datagram example wich is come with sun java wireless toolkit 2.5. for it i wrote small socket server program on c# and tested it example on my pc and its working fine. also socket server from another computer via internet working fine. But when i instal this socket example into my phone on nokia n78 (Also on nokia 5800) it's not working didn't connect to socket server.. On phone I'm using wi-fi internet. Can anybody help me with this problem? I hear it's need to modify manifest file and set appreciate pressions like this
MIDlet-Permissions: javax.microedition.io.Connector.socket,javax.microedition.io.Connector.file.write,javax.microedition.io.Connector.ssl,javax.microedition.io.Connector.file.read,javax.microedition.io.Connector.http,javax.microedition.io.Connector.https
is it true?
can anybody suggest me how can i solve this problem?
where can I read full information about socket connection specifiecs in j2me?
Thanks.

Maybe this can be helpful:
[http://download-llnw.oracle.com/javame/config/cldc/ref-impl/midp2.0/jsr118/index.html]
you can check there the Datagram interface anda DatagramConnection interface and learn a little about that.
If the client example runs fine in the wireless toolkit emulator, it should run the same way in your phone; i suggest to try to catch some exception that maybe is hapenning and display it on a Alert screen, this in the phone.

Problem with socket programming-connecting to port 13

Hi, I am learning JAVA, and we are on the subject of sockets. I am trying to make this program to connect to port 13, get the time, and print it to the console. This is my code:
import java.io.*;
import java.net.*;
public class temp {
     public static final int PORT = 13;
     public static void main(String[] args) {
          Socket s = null;
          String line = null;
          try {
               s = new Socket("localhost", PORT);
               DataInputStream sin = new DataInputStream(s.getInputStream());
               line = sin.readLine();
               if (line != null) System.out.println(line);
          catch (IOException e) {System.err.println("!" + e);}
          finally {
               try { if (s != null) s.close(); }
               catch (IOException e2) {}
And this is the output:
!java.net.ConnectException: Connection refused: connect
What should I do. I found that the problem is with the server I am connecting to and I tried connecting to dif. computers, or to stuff online, and nothing works.
Any suggestions for me?
Forgot: I tried this on both a windows XP and Vista
Edited by: xpatrickerx on Mar 23, 2008 8:12 PM
Tampering with it, I find that the error occurs on the following line:
s = new Socket("localhost", PORT);
Edited by: xpatrickerx on Mar 23, 2008 8:13 PM

So I finally found how to use printStackTrace and here is what it gives when:
1) I use my own computer:
java.net.ConnectException: Connection refused: connect
     at java.net.PlainSocketImpl.socketConnect(Native Method)
     at java.net.PlainSocketImpl.doConnect(Unknown Source)
     at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
     at java.net.PlainSocketImpl.connect(Unknown Source)
     at java.net.SocksSocketImpl.connect(Unknown Source)
     at java.net.Socket.connect(Unknown Source)
     at java.net.Socket.connect(Unknown Source)
     at java.net.Socket.<init>(Unknown Source)
     at java.net.Socket.<init>(Unknown Source)
     at temp.main(temp.java:11)
2) I use something else:
java.net.ConnectException: Connection timed out: connect
     at java.net.PlainSocketImpl.socketConnect(Native Method)
     at java.net.PlainSocketImpl.doConnect(Unknown Source)
     at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
     at java.net.PlainSocketImpl.connect(Unknown Source)
     at java.net.SocksSocketImpl.connect(Unknown Source)
     at java.net.Socket.connect(Unknown Source)
     at java.net.Socket.connect(Unknown Source)
     at java.net.Socket.<init>(Unknown Source)
     at java.net.Socket.<init>(Unknown Source)
     at temp.main(temp.java:11)
Again, thanks

Problem with socket security

Hi,
I'm trying to make socket connection from within air application, but no way. I'm browsing google for almost 2 days, follow all possible solutions, but avidently I dont understund somthing cause I'm not able to do anything.
Every time sandbox security violation..... I need make some simple socket data exchange between my air, and OS. I do not have any web server and no any other kind of network ability. I write down stupid socket server, which is waiting for policy request, and for my other requests (it function 100%, tested with Telnet, so no way to have problem on my socket server side).
The strange thing is that my application do not produce any request for socket policy file, neither at 843 port (for default), neither at my custom location with namual
Security.loadPolicyFile("xmlsocket://ip:port"); call
This is my primitive code:
<?xml version="1.0" encoding="utf-8"?>
<mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml"
    layout="vertical">
    <mx:Script>
        <![CDATA[
            private var s:XMLSocket = null;
            private function test():void{
                Security.loadPolicyFile("xmlsocket://127.0.0.1:25013");
                if(!s){
                    s = new XMLSocket();
                    s.addEventListener(DataEvent.DATA, onData);
                    s.addEventListener(Event.ACTIVATE, onActivate);
                    s.addEventListener(Event.CONNECT, onConnect);
                    s.addEventListener(Event.DEACTIVATE, onDeactivate);
                    s.addEventListener(IOErrorEvent.IO_ERROR, onError);
                    s.addEventListener(SecurityErrorEvent.SECURITY_ERROR, onSecurity);
                s.connect("127.0.0.1", 25013);
            private function onActivate(e:Event):void{
                debug.text += "Activated\r";
            private function onConnect(e:Event):void{
                debug.text += "Connected\r";
                var o:XML = <request cmd="10"/>;
                s.send(o);
            private function onDeactivate(e:Event):void{
                debug.text += "Deactivated\r";
            private function onError(e:IOErrorEvent):void{
                debug.text += e.text + "\r";
            private function onSecurity(e:SecurityErrorEvent):void{
                debug.text += e.text + "\r";
            private function onData(e:DataEvent):void{
                debug.text += e.data;
                s.close();
        ]]>
    </mx:Script>
    <mx:Button label="Test" click="test()"/>
    <mx:TextArea id="debug" width="100%" height="100%"/>
</mx:WindowedApplication>
Any help will be apresciated.
Ladislav.

Hi,
It pass some time but if i remember well, my problem was that i did
not terminate stream output form my server vs air application, and it
returns this security error.
When I send '\0' at the end of my message it work correctly. Yes the
server was my own written socket server (c++ using boost libraries).
Laco.
Sorry late response I'm on hollydays
Staney G ha scritto:
So, how did you walk around the problem? Did you have a control on how server responds?
My test case failed similarly. However, the target server is a public web service.
Will appreciate your answers!
>

Problem with socket packaging

There seems to be a problem with the plastic cpu clip i work as a tech in a computer store we build many systems with msi boards, the plastic clip on the 915G series most times has fallen off and pins in the cpu socket have been damaged.
You should use a plastic insert under the cpu hood to prevent it from falling off.

Quote
Not sure either why DelUK thinks this is not a suitable topic for this forum.
Probably because Del interpreted "You should use a plastic insert under the cpu hood to prevent it from falling off." to mean that "You" was MSI, and not the members of this forum. Oddly enough, I interpreted this the same way. I don't see where Del indicated the topic was not suitable, though.
As Del said, and as mentioned in the Forum Rules, MSI does not participate here. If you feel there is a manufacturing problem, contact MSI directly.

Problem with socket communications

I am trying to put together a client server socket communication pair.
I have one application that runs in the background acting as a server and another that can be started and stopped that acts as a client.
I can start the server and create a server socket with no problem.
I can start the client and it connects to the server.
The server acknowledges the connection and appears to go into a blocking state waiting for the client to send another message.
The server blocks at the line
parent.logit("Waiting for message from EVR..... ");
The problem is that when the client sends another message, the server doesn't hear it.
I am not sure if the problem is with the client or server communication code.
If anyone out there is a socket communication guru, I would appreciate it if you could tell me what I am doing wrong.
Thanks
Server code:
import java.io.*;
import java.net.*;
public class EVRServer
    extends Thread
EVRDataLoader parent = null;
ServerSocket serverSock = null;
Socket clientSock = null;
BufferedReader reader = null;
BufferedWriter writer = null;
int evrPort = 0;
int retryLimit = 10;
int retryCount = 0;
boolean alive = false;
boolean killSocket = false;
boolean evrConnected = false;
boolean retry = true;
EVRListener evrListener = null;
//=============================================================================
// Full constructor
//=============================================================================
   * Full constructor.
   * @param dl DataLoader - Parent application
   * @param port int Socket port
public EVRServer(EVRDataLoader dl, int port)
    parent = dl;
    evrPort = port;
//=============================================================================
// Run method - Main thread executed by start() method
//=============================================================================
   * Main thread executed by start() method
public void run()
    while (retry)
      if (retryCount > retryLimit)
        retry = false;
      parent.logit("Retry count = " + retryCount);
      // Create new server socket connection
      if (serverSock == null)
        try
          serverSock = new ServerSocket(evrPort);
          parent.logit("Created Server Socket for EVR on port " + evrPort);
          alive = true;
          killSocket = false;
          evrConnected = false;
        catch (Exception e)
          parent.logit(
              "ERROR - Could not create Server socket connection for EVR: " +
              e.toString());
          killSocket = true;
          alive = false;
      // Create new client socket connection
      if (clientSock == null)
        try
          parent.logit("Waiting for EVR to connect");
          clientSock = null;
          clientSock = serverSock.accept();
          retryCount = 0;
          evrConnected = true;
          killSocket = false;
          parent.logit("EVR connected on server Socket Port " + evrPort);
        catch (Exception e)
          parent.logit("ERROR - Error accepting EVR connection: " + e.toString());
          killSocket = true;
        try
          reader = new BufferedReader(new InputStreamReader(
              clientSock.getInputStream()));
          writer = new BufferedWriter(new OutputStreamWriter(
              clientSock.getOutputStream()));
          parent.logit( "Created reader "+reader);
          parent.logit( "Created writer "+writer);
        catch (Exception e)
          parent.logit(
              "ERROR - creating reader or writer to EVR: " + e.toString());
          killSocket = true;
      int nullCount = 0;
      while (killSocket == false)
        try
          parent.logit("Waiting for message from EVR..... ");
//          sendMessage("Data Controller connected on port " + evrPort);
          String s = reader.readLine();
          parent.logit("EVR - Received message: " + s);
          if (s != null)
            parent.processEvrMessage( s);
          else
            sleep(1000);
            nullCount++;
            if (nullCount > 10)
              parent.logit("Exceeded retry limit: ");
              killSocket = true;
        catch (Exception ex)
          parent.logit("Error Reading from EVR: " + ex.toString());
          killSocket = true;
      parent.logit( "After while loop");
      evrConnected = false;
      try
        retryCount++;
        parent.logit("Closing EVR connection. ");
        reader.close();
        writer.close();
        clientSock.close();
        writer = null;
        reader = null;
        clientSock = null;
        try
          sleep(1000);
        catch (Exception ee)
          parent.logit("Error after sleep " + ee.toString());
      catch (Exception e)
        parent.logit("Error closing EVR server socket");
//=============================================================================
// Call this method to kill the client socket connection.
//=============================================================================
   * Call this method to kill the client socket connection.
public void killConnection()
    killSocket = true;
//=============================================================================
// Return RTM connected state
//=============================================================================
   * Return RTM connected state
   * @return boolean - Returns true if RTM is connected to server, false if not.
public boolean isRtmConnected()
    return evrConnected;
//=============================================================================
// Returns state of server socket.
//=============================================================================
   * Returns state of server socket.
   * @return boolean - Returns true if server socket is enabled, false if not.
public boolean isServerSocketAlive()
    return alive;
//=============================================================================
// Send a message to the client socket.
//=============================================================================
     * Send a message to the client socket.
     * @param msg String - Message to send.
     * @return boolean - Returns true if message sent OK, false if not.
public boolean sendMessage(String msg)
    parent.logit(" In EVR Server - Send Message - got message: " + msg);
    if (evrConnected)
      try
        parent.logit("Sending message to EVR: " + msg);
        writer.write(msg + "\n");
        writer.flush();
        return true;
      catch (Exception e)
        parent.logit("ERROR - Error sending message to EVR: " + e.toString());
        return false;
    else
      parent.logit("EVR not connected, cannot send message: " + msg);
      return false;
}Client code:
package evrsimulator;
import java.net.*;
import java.io.*;
class PortConnector
      extends Thread
   ServerSocket serverSock = null;
   boolean isIP = false;
   InetAddress addr = null;
   Frame1 parent = null;
   byte[] rawIP;
    //   String initialMsg = "";
   public PortConnector( Frame1 f )
     parent = f;
   // This method is called when the thread runs
   public void run()
      if ( parent.hostName.indexOf( "." ) > 0 )
         isIP = true;
         byte[] rawIP = parent.getRawIP( parent.hostName );
      try
         System.out.println( "Connecting to host " +
                                        parent.hostName + " on port " +
                                        parent.socketPort );
         if ( isIP )
            addr = InetAddress.getByAddress( rawIP );
         else
            addr = InetAddress.getByName( parent.hostName );
         System.out.println( "Inet address = " + addr );
         SocketAddress sockaddr =
               new InetSocketAddress( addr, parent.socketPort );
         // Create an unbound socket
         parent.client = new Socket();
         // This method will block no more than timeoutMs.
         // If the timeout occurs, SocketTimeoutException is thrown.
         parent.client.connect( sockaddr, parent.socketTimeOut );
         parent.socketOut =
               new BufferedWriter( new OutputStreamWriter(
               parent.client.getOutputStream() ) );
         parent.socketIn = new BufferedReader( new InputStreamReader(
               parent.client.getInputStream() ) );
         parent.localName = parent.localName +
               parent.client;
         System.out.println( "Parent socketOut = "+parent.socketOut);
         System.out.println( "Parent socketIn = "+parent.socketIn);
      catch ( UnknownHostException uhe )
         System.out.println( "Unknown Host - " + uhe.getMessage() );
      catch ( SocketTimeoutException ste )
         System.out.println( "Socket time out - " + ste.getMessage());
      catch ( IOException ioe )
         System.out.println( "IO exception - " + ioe.getMessage() );
      // Listen on socket for message from host - thread should block.
      parent.portConnected = true;
      while ( parent.portConnected )
         try
            String msg = parent.socketIn.readLine();
            System.out.println( "Message from Host: " + msg );
            System.out.println( "Message from Host: |" + msg + "|" );
            if( msg.length() > 2)parent.processMessage( msg );
         catch ( IOException ioe )
            System.out.println( "Exception creating server socket." );
      try
         System.out.println(
               "PortConnection - Closing socket and IO connections" );
         parent.socketIn.close();
         parent.socketOut.close();
         parent.client.close();
         parent.clockRunning = false;
         if( parent.heartBeating) heartBeat.interrupt();
      catch ( IOException ioex )
         System.out.println( "Exception closing socket." );
}

Your first problem is that you keep closing and recreating the ServerSocket. Do this once only in the lifetime of the server.
This is such a basic error that I haven't read the rest of the code. Before you go any further I suggest you read the Custom Networking trail of the Java Tutorial.

Problem with Socket Sever

Hello,
I have a problem with a java socket.
I have a server application that generate random number.
I my client application, I connected to server application and red the random number.
My problem is in my application client only read one time. After this, the socket server application close.
How to do the server socket wait a new request from my client application?

Put your accept in a while ....
while (!this.interrupted()) {
Socket socket;
try {
socket = serverSocket.accept();
if (this.isInterrupted()) {
return;
new ClientConnection(); ///////Do your thing here ...
} catch (IOException e) {
return;
HOPE this helps

Problem with socket - Client in C and Server in Java

Hi,
I am building a Java based TCP server socket class in Windows machine. The client is written in C running in Linux.
The client sends data in specified C struct: Eg.
{noformat}struct person {
    int   age;
    float weight;
    int height;
} I am having problem reading it in Java Server. I am using DataInputStream to read byte and trying to decode it in age, float etc. the problem is I can read first two but I cannot properly decode the 'height'.
My question is it possible to directly cast the input stream in corresponding Java object? I guess not but would like to know your ideas.
Is it a good idea to send the struct instead of string?
regards,
rnv

You are perpetrating mistake #1 here. Don't try to send C structs over the wire. The format is dependent on the hardware, the operating system, the compiler, the compiler version, compiler bugs, the #pragmas, and the compiler options in effect. Too many variables. What you should be doing is writing the primitive types to the network, in network byte order, and reading them inJava with the appropriate methods of DataInputStream.

Problem with socket in java and c++

I am connecting to a server developed in java that use sys/socket.h, this server use DataInputStream
class and readUTF so:
in = new DataInputStream(socket.getInputStream());
inputString = in.readUTF()
My application in C++ it use winsock2.h and I utilize the method "send" in order to send the plots to the server
java got hold of:
#define MAXLONGITUD 10000
char bufEnviados[MAXLONGITUD + 1];
bufEnviados[0] = (0xff & (longitud >> 8));
bufEnviados[1] = (0xff & longitud);
send(sock, bufEnviados,strlen(bufEnviados), 0 );
I send the two first characters with UTF format so that the server in java could recognize them.
The application operated correctly it until received an old plot of 6.236 characters later
from which it close the connection with the socket and it fall my application!
I have carried out several tests and I don't succeed in sending more than those 6.236 characters, however it achievement receibing whatever quantity of characters without problems!
Could somebody help me to resolve this problem? I am attempting of everything and I don't achieve it!
Ahead of time thank you!

alfaximena wrote:
#define MAXLONGITUD 10000
char bufEnviados[MAXLONGITUD + 1];
bufEnviados[0] = (0xff & (longitud >> 8));
bufEnviados[1] = (0xff & longitud);
send(sock, bufEnviados,strlen(bufEnviados), 0 );
Are you sending characters or binary data? You mention "plot" which sounds like binary data. You cannot send binary data via character encoding. Characters in java are not just bits, they are mapped values. If you encode it with something like base64 then that should be ok.
I can only suppose that your testing was with data sets greater than 255, because strlen() would not have worked otherwise.
Since you have the size then use it rather than using strlen().
I send the two first characters with UTF format so that the server in java could recognize them.
The application operated correctly it until received an old plot of 6.236 characters later
from which it close the connection with the socket and it fall my application!
There is nothing special about that particular number. So I would guess that the data in that set is the problem. Probably because you are in fact sending binary data. If, for example, a byte with a value of zero showed up in the sequence then strlen() would return an incorrect value compared to the size that you told java you are sending.

Problem with socket and object writing

Hi,
I programm this client/server app, the client has a point (graphic ) , the server has a point and when the mouse is moving it moves the point and the new position is send via the socket.
The probleme is that i don't receive the good thing.
When i display the coord of the point before sending it's good , but when receiving from the socket the coords are always the same ...
i don't understand .
Well , try and tell me ...
Thx.

oups, the program can be usefull ...
import java.applet.*;
import java.awt.*;
import java.util.*;
import java.awt.event.*;
public class server_JFrame extends javax.swing.JFrame implements MouseListener,MouseMotionListener{
point p1,p2;
server s;
public server_JFrame()
this.setSize(600,400);
addMouseListener(this);
addMouseMotionListener(this);
p2=new point(50,50,new Color(0,0,255));
p1=new point(200,200,new Color(255,0,0));
s = new server(p2,this);
public void paint(Graphics g)
super.paint(g);
g.setColor(p1.get_color());
g.fillOval(p1.get_x(), p1.get_y(),10,10);
g.setColor(p2.get_color());
g.fillOval(p2.get_x(), p2.get_y(),10,10);
public void mouseClicked(MouseEvent e) { }
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {}
public void mouseDragged(MouseEvent e) {}
public void mouseMoved(MouseEvent e)
p1.set_x(e.getX());
p1.set_y(e.getY());
s.write_point(p1);
repaint();
public static void main(String args[])
     server_JFrame sjf = new server_JFrame();
sjf.setDefaultCloseOperation(EXIT_ON_CLOSE);
     sjf.setTitle("server");
sjf.show();
import java.io.*;
import java.net.*;
import java.util.*;
import java.awt.*;
public class server {
point p_;
Container c_;
ObjectInputStream Istream_;
ObjectOutputStream Ostream_;
public server(point p,Container c)
p_=p;
c_=c;
try
ServerSocket server = new java.net.ServerSocket(80);
System.out.println("attente d'un client");
java.net.Socket client = server.accept();
System.out.println("client accept�");
Istream_ = new ObjectInputStream(client.getInputStream());
Ostream_ = new ObjectOutputStream(client.getOutputStream());
ThreadRead tr = new ThreadRead(Istream_,p_,c_);
catch (Exception exception) { exception.printStackTrace(); }
public void write_point(point p)
try
System.out.print("x="+p.get_x());
System.out.println(" y="+p.get_y());
Ostream_.flush();
Ostream_.writeObject(p);
Ostream_.flush();
catch (Exception exception) {exception.printStackTrace();}
import java.applet.*;
import java.awt.*;
import java.util.*;
import java.awt.event.*;
public class client_JFrame extends javax.swing.JFrame implements MouseListener,MouseMotionListener{
point p1,p2;
client c;
public client_JFrame()
this.setSize(600,400);
addMouseListener(this);
addMouseMotionListener(this);
p1=new point(50,50,new Color(0,0,255));
p2=new point(200,200,new Color(255,0,0));
c = new client(p2,this);
public void paint(Graphics g)
super.paint(g);
g.setColor(p1.get_color());
g.fillOval(p1.get_x(), p1.get_y(),10,10);
g.setColor(p2.get_color());
g.fillOval(p2.get_x(), p2.get_y(),10,10);
public void mouseClicked(MouseEvent e) { }
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {}
public void mouseDragged(MouseEvent e) {}
public void mouseMoved(MouseEvent e)
p1.set_x(e.getX());
p1.set_y(e.getY());
c.write_point(p1);
repaint();
public static void main(String args[])
     client_JFrame cjf = new client_JFrame();
cjf.setDefaultCloseOperation(EXIT_ON_CLOSE);
     cjf.setTitle("client");
cjf.show();
import java.io.*;
import java.net.*;
import java.util.*;
import java.awt.*;
public class client {
point p_;
Container c_;
ObjectInputStream Istream_;
ObjectOutputStream Ostream_;
public client(point p,Container c)
p_=p;
c_=c;
try
ipJDialog ipjd = new ipJDialog();
String ip = ipjd.getvalue();
Socket socket = new Socket(ip,80);
System.out.println("connection avec serveur reussi");
Ostream_ = new ObjectOutputStream(socket.getOutputStream());
Istream_ = new ObjectInputStream(socket.getInputStream());
ThreadRead tr = new ThreadRead(Istream_,p_,c_);
catch (Exception exception) {*exception.printStackTrace();*/System.out.println("connection avec serveur echou�");}
public void write_point(point p)
try
System.out.print("x="+p.get_x());
System.out.println(" y="+p.get_y());
Ostream_.flush();
Ostream_.writeObject(p);
Ostream_.flush();
catch (Exception exception) {exception.printStackTrace();}
import java.io.*;
import java.net.*;
import java.util.*;
import java.awt.*;
public class client {
point p_;
Container c_;
ObjectInputStream Istream_;
ObjectOutputStream Ostream_;
public client(point p,Container c)
p_=p;
c_=c;
try
ipJDialog ipjd = new ipJDialog();
String ip = ipjd.getvalue();
Socket socket = new Socket(ip,80);
System.out.println("connection avec serveur reussi");
Ostream_ = new ObjectOutputStream(socket.getOutputStream());
Istream_ = new ObjectInputStream(socket.getInputStream());
ThreadRead tr = new ThreadRead(Istream_,p_,c_);
catch (Exception exception) {*exception.printStackTrace();*/System.out.println("connection avec serveur echou�");}
public void write_point(point p)
try
System.out.print("x="+p.get_x());
System.out.println(" y="+p.get_y());
Ostream_.flush();
Ostream_.writeObject(p);
Ostream_.flush();
catch (Exception exception) {exception.printStackTrace();}
import java.io.Serializable;
import java.awt.*;
public class point implements Serializable{
private int x_;
private int y_;
private Color c_;
public point(int x, int y, Color c) {
x_=x;
y_=y;
c_=c;
public int get_x() { return x_ ; }
public int get_y() { return y_ ; }
public void set_x(int x) { x_=x ; }
public void set_y(int y) { y_=y ; }
public Color get_color() { return c_ ; }
}

Problem in socket...

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