socketsjavafxhashmaphashtableserversocket
Send Message to All in Client Server Chat Application in JavaFX
I was able to send message to clients connected to server but when
- When Client Bunny sends message to Joel(receives message) and vice versa.
- When second time Bunny sends message to Joel (doesn't receive message).
How do I iterate hashtable loop again to send and receive messages.
Server Class
import java.io.*; //Input and output to read and write data.
import java.net.*; //serversocket and initaddress
import java.util.Date; //to get date
import java.util.Enumeration; //enumeration
import java.util.Hashtable; // hashtable
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import javafx.application.Application; //
import javafx.application.Platform; //platformrun later to append text
import javafx.event.EventHandler; // on click actions
import javafx.geometry.Insets; //insets
import javafx.geometry.Pos; //position
import javafx.scene.Scene; //scene
import javafx.scene.control.TextArea; //textarea
import javafx.scene.layout.StackPane; //stackpane
import javafx.stage.Stage; //stage
import javafx.stage.WindowEvent; //event close
public class Server extends Application { //class server
static InetAddress inetAddress; //inetaddress
private final Hashtable<Object, Object> outputStreams = new Hashtable(); //hashtable
TextArea textarea = new TextArea(); //textarea
static DataInputStream inputFromClient = null; //datainputstream
static DataOutputStream outputToClient = null; //dataoutputstream
static int clientNo = 0; //client connected
static ServerSocket serverSocket; //server socket
Hashtable<Object, Object> hmap = new Hashtable<>();
@Override // Override the start method in the Application class
public void start(Stage primaryStage) { //Stage to show everything
StackPane root = new StackPane(); //root add all the elements
root.setPadding(new Insets(10, 10, 10, 10)); //padding
root.setAlignment(textarea, Pos.CENTER); //positioning textarea to center
textarea.setMaxSize(400, 400); //maxsize of textarea
textarea.setWrapText(true); //wraptext for the textarea
new Thread(() -> { //thread to hold the server for the connections
try {
// Create a server socket
ServerSocket serverSocket = new ServerSocket(8001); //The server creates a server socket and, once a connection to a client is established, connects to the client with a client socket.
textarea.appendText("MultiThreadServer started at " + new Date() + '\n'); //server started with date.
while (true) { //accept multiple connections
// Listen for a new connection request
Socket socket = serverSocket.accept(); //listening for new connection from server port.
// inputFromClient = new DataInputStream(socket.getInputStream());
outputToClient = new DataOutputStream(socket.getOutputStream()); //outputstream to output to client
// Increment clientNo
clientNo++;
Platform.runLater(() -> {
// Display the client number
textarea.appendText("Starting thread for client " + clientNo + " at " + new Date() + '\n');
// Find the client's host name, and IP address
InetAddress inetAddress = socket.getInetAddress();
textarea.appendText("Client " + clientNo + "'s host name is " + inetAddress.getHostName() + "\n");
textarea.appendText("Client " + clientNo + "'s IP Address is " + inetAddress.getHostAddress() + "\n");
});
HandleAClient hd = new HandleAClient(socket);
hmap.put(socket, outputToClient);
hd.start();
// outputStreams.put(socket, outputToClient); //using hashtable to store client socket and outputstream
// Create and start a new thread for the connection
// new HandleAClient(this, socket);
}
} catch (IOException ex) {
textarea.appendText(ex + " \n");
}
}).start();
root.getChildren().addAll(textarea); // add UI elements to the root
Scene scene = new Scene(root, 450, 400); // creating scene of size 450 width and height 500
primaryStage.setTitle("Server"); // Set the stage title
primaryStage.setScene(scene); // Place the scene in the stage
primaryStage.show(); // Display the stage
primaryStage.setOnCloseRequest(new EventHandler<WindowEvent>() { //close scene
@Override
public void handle(WindowEvent t) {
primaryStage.close();
Platform.exit();
System.exit(0);
}
});
}
// Used to get the output streams
Enumeration getOutputStreams() {
return outputStreams.elements();
}
// Used to send message to all clients
void sendToAll(String message) {
// Go through hashtable and send message to each output stream
for (Enumeration e = getOutputStreams(); e.hasMoreElements();) {
DataOutputStream dout = (DataOutputStream) e.nextElement();
try {
// Write message
dout.writeUTF(message);
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
class HandleAClient extends Thread {
private Socket socket; // A connected socket
private String text = "";
/**
* Construct a thread
*/
public HandleAClient(Socket socket) throws IOException {
this.socket = socket;
}
/**
* Run a thread
*/
public void run() {
try {
// Create data input stream
inputFromClient = new DataInputStream(socket.getInputStream()); //receive input from client
textarea.appendText(new Date() + " Connection from " + socket + "\n");//showing connection from client
text = inputFromClient.readUTF(); // read string or message from client
// serversocket.sendToAll(text);
Set set = hmap.entrySet();
Iterator it = set.iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
System.out.println("key " + entry.getKey() + " : " + entry.getValue());
DataOutputStream dout = (DataOutputStream) entry.getValue();
dout.writeUTF(text);
dout.flush();
}
Platform.runLater(() -> {
textarea.appendText(new Date() + " " + text + "\n");//append text
});
} catch (IOException e) {
textarea.appendText("Error " + e + " \n");
try {
this.socket.close(); //socket close
} catch (IOException ex) {
textarea.appendText("Error " + e + " \n");
}
e.printStackTrace();
}
}
}
public static void main(String[] args) { //The keyword void simply tells the compiler that main( ) does not return a value.
launch(args);
}
}
Client Class
import java.io.*; //Input and output to read and write data.
import java.net.*; //serversocket and initaddress
import javafx.application.Application; //
import javafx.application.Platform; //platformrun later to append text
import javafx.event.EventHandler; // on click actions
import javafx.geometry.Insets; //insets
import javafx.geometry.Pos; //position
import javafx.scene.Scene; //scene
import javafx.scene.control.TextArea; //textarea
import javafx.scene.layout.StackPane; //stackpane
import javafx.stage.Stage; //stage
import javafx.stage.WindowEvent; //event close
import javafx.scene.control.Button; // button
import javafx.scene.control.Label; //label
import javafx.scene.control.TextField; //textfield
public class Client extends Application {
// IO streams
static DataOutputStream toServer = null; //datainputstream
static DataInputStream fromServer = null; //dataoutputstream
Label usernamelabel = new Label("Set your name :"); //set name label
Label textarealabel = new Label("Type your message in the textarea"); //text label
Label textlabel = new Label("Enter Text :"); //enter text
TextField textfield = new TextField(); //textfield
TextField namefield = new TextField(); //name field
Button send = new Button("Send"); //sendbutton
TextArea messagefield = new TextArea(); //textarea
static ServerSocket serverSocket; //serversocket
// Override the start method in the Application class
public void start(Stage primaryStage) throws IOException {
StackPane root = new StackPane(); //stacpane
root.setPadding(new Insets(10, 10, 10, 10));
StackPane.setAlignment(usernamelabel, Pos.TOP_LEFT);
namefield.setMaxWidth(200);
StackPane.setAlignment(namefield, Pos.TOP_CENTER);
StackPane.setMargin(textlabel, new Insets(30, 0, 0, 0));
StackPane.setMargin(textfield, new Insets(30, 0, 0, 0));
StackPane.setAlignment(textlabel, Pos.TOP_LEFT);
textfield.setMaxWidth(200);
StackPane.setAlignment(textfield, Pos.TOP_CENTER);
StackPane.setAlignment(send, Pos.BOTTOM_CENTER);
messagefield.setMaxSize(450, 250);
StackPane.setAlignment(textarealabel, Pos.BOTTOM_CENTER);
StackPane.setMargin(textarealabel, new Insets(0, 0, 35, 0));
StackPane.setAlignment(messagefield, Pos.CENTER);
root.getChildren().addAll(usernamelabel, namefield, send, messagefield, textarealabel, textlabel, textfield); //adding all the UI elements
// Create a scene and place it in the stage
Scene scene = new Scene(root, 500, 400);
primaryStage.setTitle("Client"); // Set the stage title
primaryStage.setScene(scene); // Place the scene in the stage
primaryStage.show(); // Display the stage
send.setOnAction(e -> { //send button action
try {
if (namefield.getText().trim().length() == 0) { //name field is empty
messagefield.appendText("Name field is empty. Please enter your name\n");
} else if (textfield.getText().trim().length() == 0) { //message field is empty
messagefield.appendText("Message field is empty. Please enter your message to send\n");
}
// Send the radius to the server
if (namefield.getText().trim().length() > 0 && textfield.getText().trim().length() > 0) {
toServer.writeUTF(namefield.getText().trim() + " : " + textfield.getText().trim());
toServer.flush();
}
} catch (IOException ex) {
messagefield.appendText(ex+" \n");
}
});
try {
// Create a socket to connect to the server
Socket socket = new Socket("localhost", 8001); //socket with port number to connect server
// Create an output stream to send data to the server
toServer = new DataOutputStream(socket.getOutputStream());
new ReceiveMessage(socket); // send socket receieve class
// }
} catch (Exception ex) {
messagefield.setText(ex.toString() + '\n');
}
primaryStage.setOnCloseRequest(new EventHandler<WindowEvent>() { //scene close
@Override
public void handle(WindowEvent t) {
Platform.exit();
System.exit(0);
}
});
}
class ReceiveMessage implements Runnable { //class receive message
private final Socket socket;//socket
public ReceiveMessage(Socket socket) { // constructor
this.socket = socket; //socket intializes
Thread thread = new Thread(this);
thread.setDaemon(true);
thread.start();
}
public void run() {
try {
fromServer = new DataInputStream(socket.getInputStream()); //to read from server
while (true) { // to continously receieve messages
// Get area from the server
String textmessage = fromServer.readUTF(); //read message from server
toServer.flush(); // flush
Platform.runLater(() -> {
messagefield.appendText(textmessage + " \n"); //append to textarea
});
}
} catch (IOException e) {
messagefield.appendText("Error " + e);
}
}
}
public static void main(String[] args) { //The keyword void simply tells the compiler that main( ) does not return a value.
launch(args);
}
}
Server class executed and taking clients
Client one connected
Client Two connected
Thank you.
Solution
The mistake I made in the code was after client sends message to server and sends message to all the clients connected to the server after that server connection is paused or halted I don't know why. I have used enumeration method to send messages to all the clients connected to the server. This is how I solved the issue. Hope my answer will help someone who is trying to implement client-server (multiple clients) chat application using thread.
import java.io.*;
import java.net.*;
import java.util.ArrayList;
import java.util.Date;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.TextArea;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import javafx.stage.WindowEvent;
public class Server extends Application {
static InetAddress inetAddress;
private final Hashtable<Object, Object> outputStreams = new Hashtable();
TextArea textarea = new TextArea();
static int clientNo = 0;
static ServerSocket serverSocket;
Hashtable<Object, Object> hmap = new Hashtable<>();
ArrayList<Object> clients = new ArrayList<Object>();
public void start(Stage primaryStage) {
StackPane root = new StackPane();
root.setPadding(new Insets(10, 10, 10, 10));
root.setAlignment(textarea, Pos.CENTER);
textarea.setMaxSize(400, 400);
textarea.setWrapText(true);
root.getChildren().addAll(textarea);
Scene scene = new Scene(root, 450, 400);
primaryStage.setTitle("Server");
primaryStage.setScene(scene);
primaryStage.show(); // Display the stage
primaryStage.setOnCloseRequest(new EventHandler<WindowEvent>() {
@Override
public void handle(WindowEvent t) {
primaryStage.close();
Platform.exit();
System.exit(0);
}
});
new Thread(() -> {
listen();
}).start();
}
private void listen() {
try {
// Create a server socket
serverSocket = new ServerSocket(8001);
textarea.appendText("MultiThreadServer started at " + new Date() + '\n');
while (true) {
Socket socket = serverSocket.accept();
inputFromClient = new DataInputStream(socket.getInputStream());
DataOutputStream outputToClient = new DataOutputStream(socket.getOutputStream());
clientNo++;
Platform.runLater(() -> {
textarea.appendText("Starting thread for client " + clientNo + " at " + new Date() + '\n');
InetAddress inetAddress = socket.getInetAddress();
textarea.appendText("Client " + clientNo + "'s host name is " + inetAddress.getHostName() + "\n");
textarea.appendText("Client " + clientNo + "'s IP Address is " + inetAddress.getHostAddress() + "\n");
});
hmap.put(socket, outputToClient);
new HandleAClient(socket);
}
} catch (IOException ex) {
textarea.appendText(ex + " \n");
}
}
Enumeration getOutputStreams() {
return hmap.elements();
}
void sendToAll(String message) {
for (Enumeration e = getOutputStreams(); e.hasMoreElements();) {
DataOutputStream dout = (DataOutputStream) e.nextElement();
try {
dout.writeUTF(message);
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
void All(String text) throws IOException {
Set set = hmap.entrySet();
Iterator it = set.iterator();
System.out.println("Text " + text);
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
System.out.println("key " + entry.getKey() + " : " + entry.getValue());
DataOutputStream dout = (DataOutputStream) entry.getValue();
dout.writeUTF(text);
dout.flush();
}
}
class HandleAClient extends Thread {
private final Socket socket; // A connected socket
private String text = "";
/**
* Construct a thread
*/
public HandleAClient(Socket socket) throws IOException {
this.socket = socket;
start();
}
/**
* Run a thread
*/
public void run() {
try {
DataInputStream inputFromClient = new DataInputStream(socket.getInputStream()); //receive input from client
while (true) {
textarea.appendText(new Date() + " Connection from " + socket + "\n");
text = inputFromClient.readUTF();
serversocket.sendToAll(text);
All(text);
Platform.runLater(() -> {
textarea.appendText(new Date() + " " + text + "\n");
});
}
} catch (IOException e) {
textarea.appendText("Error " + e + " \n");
try {
this.socket.close();
} catch (IOException ex) {
textarea.appendText("Error " + e + " \n");
}
e.printStackTrace();
}
}
}
public static void main(String[] args) { //The keyword void simply tells the compiler that main( ) does not return a value.
launch(args);
}
}
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