A qt client connect with a java server
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I have a problem when I am trying to send a msg from my qt client to java server.
this is the java code, the error that i take is " ID ERROR reading: null "
@ public void run() {
System.out.println("Server Thread " + ID + " running.");
while (true) {
try {
server.handle(ID, DataInputStream.readUTF());
}
catch (IOException ioe) {
System.out.println(ID + " ERROR reading: " + ioe.getMessage());
server.remove(ID);
stop();
}
}
}
@my void in Qt client for send a msg is
@void MainWindow::sendTheMsg()
{
QByteArray buffer;
buffer.append(nickName);
buffer.append(": ");
buffer.append(ui->lineEdit->text());
socket->write("<i>"+buffer+"</i>");
qDebug() << buffer;}
@also I have tried to change the encode to UTF8 with this code
@ QString qtext = "Hello";
socket->write(qtext.toUtf8());
@but nothing!
any idea plz!
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Since you have not provided the initialization part for server nor for client I assume that you checked all possible errors during initialization.
Have you tried to send anything to the Java server from another application, "netcat":http://netcat.sourceforge.net/ or "ncat":http://nmap.org/ncat/ for example?
Have you tried to use the same tools to receive anything from Qt client?
Try to run "wireshark":http://www.wireshark.org/ to see what happens between client and server.
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my server is the following
chatServer.java
@import java.net.;
import java.io.;public class ChatServer implements Runnable {
private ChatServerThread clients[] = new ChatServerThread[50];
private ServerSocket server = null;
private Thread thread = null;
private int clientCount = 0;public ChatServer(int port) {
try {
System.out.println("Binding to port " + port + ", please wait ...");
server = new ServerSocket(port);
System.out.println("Server started: " + server);
start();
} catch (IOException ioe) {
System.out.println("Can not bind to port " + port + ": " + ioe.getMessage());
}
}public void run() {
while (thread != null) {
try {
System.out.println("Waiting for a client ...");
addThread(server.accept());
} catch (IOException ioe) {
System.out.println("Server accept error: " + ioe);
stop();
}
}
}public void start() {
if (thread == null) {
thread = new Thread(this);
thread.start();
}
}public void stop() {
if (thread != null) {
thread.stop();
thread = null;
}
}private int findClient(int ID) {
for (int i = 0; i < clientCount; i++)
if (clients[i].getID() == ID)
return i;
return -1;
}public synchronized void handle(int ID, String input) {
if (input.equals(".bye")) {
clients[findClient(ID)].send(".bye");
remove(ID);
} else
for (int i = 0; i < clientCount; i++)
clients[i].send(ID + ": " + input);
}public synchronized void remove(int ID) {
int pos = findClient(ID);
if (pos >= 0) {
ChatServerThread toTerminate = clients[pos];
System.out.println("Removing client thread " + ID + " at " + pos);
if (pos < clientCount - 1)
for (int i = pos + 1; i < clientCount; i++)
clients[i - 1] = clients[i];
clientCount--;
try {
toTerminate.close();
} catch (IOException ioe) {
System.out.println("Error closing thread: " + ioe);
}
toTerminate.stop();
}
}private void addThread(Socket socket) {
if (clientCount < clients.length) {
System.out.println("Client accepted: " + socket);
clients[clientCount] = new ChatServerThread(this, socket);
try {
clients[clientCount].open();
clients[clientCount].start();
clientCount++;
} catch (IOException ioe) {
System.out.println("Error opening thread: " + ioe);
}
} else
System.out.println("Client refused: maximum " + clients.length + " reached.");
}public static void main(String args[]) {
ChatServer server = null;
if (args.length != 1)
System.out.println("Usage: java ChatServer port");
else
server = new ChatServer(Integer.parseInt(args[0]));
}}
@and ChatServerThread.java
@import java.net.;
import java.io.;public class ChatServerThread extends Thread {
private ChatServer server = null;
private Socket socket = null;
private int ID = -1;
private DataInputStream streamIn = null;
private DataOutputStream streamOut = null;public ChatServerThread(ChatServer _server, Socket _socket) {
super();
server = _server;
socket = _socket;
ID = socket.getPort();
}public void send(String msg) {
try {
streamOut.writeUTF(msg);
streamOut.flush();
streamOut.writeUTF("writeUTF");
streamOut.writeInt(1234);} catch (IOException ioe) {
System.out.println(ID + " ERROR sending: " + ioe.getMessage());
server.remove(ID);
stop();
}
}public int getID() {
return ID;
}public void run() {
System.out.println("Server Thread " + ID + " running.");
while (true) {
try {
server.handle(ID, streamIn.readUTF());
} catch (IOException ioe) {
System.out.println(ID + " ERROR reading: " + ioe.getMessage());
server.remove(ID);
stop();
}
}
}public void open() throws IOException {
streamIn = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
streamOut = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
}public void close() throws IOException {
if (socket != null)
socket.close();if (streamIn != null)
streamIn.close();if (streamOut != null)
streamOut.close();
}
}
@but I cant change the code of server..only the client side which is written in Qt.
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What you will get if you try to read input without processing it.
@
public void run() {
System.out.println("Server Thread " + ID + " running.");
while (true) {
try {
System.out.println(streamIn.readUTF());
//server.handle(ID, streamIn.readUTF());
} catch (IOException ioe) {
System.out.println(ID + " ERROR reading: " + ioe.getMessage());
server.remove(ID);
stop();
}
}
}
@[EDIT] Did you try to use wireshark and, or netcat?
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Have you tried another client like ncat or netcat ?
Have you tried wireshark to see what is sent ?[quote author="parkir" date="1407169299"]But when I use the Qt client with a server written in Qt, everything is ok and respectively for the java client and server.[/quote]
You can compare what is sent between a Java client and Java Server with Qt client and Java server using wireshark.
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IIRC(If I Memeber Correctly) Zenmap is for scanning the computer ports not for sniffing a traffic.
But anyway. I tested your java code and simple client. My client connects to server, sends text and disconnect.
I see that client connect to java server and sends text and disconnect.
The error message 55130 ERROR reading: null appears when a client is disconnected, which is ok.The same happens if I use ncat.
I don't see that ChatServer::handle() is called. I guess something should be done in the server to process the input.
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Here is modified ChatServerThread.java that works.
At least as I think it should work.public class ChatServerThread extends Thread
{
private ChatServer server = null;
private Socket socket = null;
private int ID = -1;
private BufferedReader streamIn = null;
private BufferedWriter streamOut = null;public ChatServerThread(ChatServer _server, Socket _socket)
{
super();
server = _server;
socket = _socket;
ID = socket.getPort();
}public void send(String msg)
{
try {
streamOut.write(msg + "\n");
streamOut.flush();
}
catch (IOException ioe) {
System.out.println(ID + " ERROR sending: " + ioe.getMessage());
server.remove(ID);
stop();
}
}public int getID()
{
return ID;
}public void run()
{
System.out.println("Server Thread " + ID + " running.");
while (true) {
try {
String input = streamIn.readLine();
if (input != null) {
server.handle(ID, input);
} else {
System.out.println(ID + " we lost the client :-(.\n");
server.remove(ID);
stop();
}
}
catch (IOException ioe) {
System.out.println(ID + " ERROR reading: " + ioe.getMessage());
server.remove(ID);
stop();
}
}
}public void open() throws IOException
{
streamIn =
new BufferedReader(new InputStreamReader(socket.getInputStream()));
streamOut =
new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
}public void close() throws IOException
{
if (socket != null)
socket.close();if (streamIn != null) streamIn.close(); if (streamOut != null) streamOut.close();}
}
@ -
I think so the problem is the client..
I post you the mainwindow.cpp
@#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QStackedWidget>
#include "about.h"
#include <QMessageBox>MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);//set background color setStyleSheet("background-color: rgb(87,87,87)"); //the login group ui->loginGroup->setStyleSheet("background-color: rgb(112,128,144); color:white"); //button ui->btn_login->setStyleSheet("QPushButton { background-color: rgb(176,196,222); color:black }"); ui->btnSend->setStyleSheet("QPushButton { background-color: rgb(176,196,222); color:black }"); //label ui->label_welcome->setStyleSheet("QLabel {font-family:Pristina; font-size: 30px; color:white;}"); //QlineEdit ui->txt_nickname->setStyleSheet("QLineEdit {background-color: white; color:black}"); ui->txt_serverIP->setStyleSheet("QLineEdit {background-color: white; color:black}"); ui->msgArea->setStyleSheet("QLineEdit {background-color: white; color:black}"); //the place who display everything from the chat room ui->roomTextMsg->setStyleSheet("background-color: rgb(112,128,144); color:white"); //set the IP of my server ui->txt_serverIP->setText("localhost"); //menu bar ui->menuAbout->setStyleSheet("background-color: rgb(112,128,144); color:white"); socket = new QTcpSocket(this); ui->stackedWidget->setCurrentWidget(ui->loginPage); //socket->write(QString("\n"+nickName ).toUtf8()); connect(socket, SIGNAL(readyRead()), this, SLOT(readyRead())); connect(socket, SIGNAL(connected()), this, SLOT(connected()));}
MainWindow::~MainWindow()
{
delete ui;
thread->deleteLater();
}void MainWindow::displayMsg(QByteArray sentMsg)
{
QString msg = QString(sentMsg.data());
ui->roomTextMsg->append(msg);
}void MainWindow::sendTheMsg()
{
QByteArray buffer;
buffer.append(nickName);
buffer.append(": ");
buffer.append(ui->msgArea->text());
socket->write("<i>"+ buffer +"</i>");
qDebug() << buffer;ui->msgArea->clear();}
void MainWindow::on_btnSend_clicked()
{
if( !(ui->msgArea->text() == ""))
{
sendTheMsg();
}
}void MainWindow::readyRead()
{
thread = new QThread();
ui->roomTextMsg->append(socket->readAll());
socket->flush();
socket->waitForBytesWritten(3000);socket->moveToThread(thread); thread->start();}
void MainWindow::on_btn_login_clicked()
{
nickName = ui->txt_nickname->text().trimmed();socket->connectToHost(ui->txt_serverIP->text(), 1234); socket->waitForConnected(3000);}
void MainWindow::connected()
{
// Flip over to the chat page:
ui->stackedWidget->setCurrentWidget(ui->chatRoom);// And send our username to the chat server. socket->write(QString("\n"+nickName + " ..connected\n").toUtf8());--}
void MainWindow::on_msgArea_returnPressed()
{
if( !(ui->msgArea->text() == ""))
{
sendTheMsg();
}
}
@
this is the client code..this code I have to change and me it to communicate with the server..but I cant find why cannot send and recieve a msg