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.
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);
}
}
I must to do chat server for my subject.
Where is my problem ?
I need to write UDP server class which should send and receive messages from users and transfer it to GUI
Second server should have methods for collect public keys of any user, changing owns ect. Additionally he should store this these keys
What do I have?
I have some code from first server, two Threads for sending and receiving messages and some code in client , but it isn't synchronized. And I don't know how to do it
This is some code from client main method: tfServer --> text field for getting this from user
InetAddress ia = InetAddress.getByName(tfServer.getText());
SenderThread sender = new SenderThread(ia,Integer.valueOf(tfPort.getText()));
sender.start();
ReceiverThread receiver = new ReceiverThread(sender.getSocket());
receiver.start();
First server code :
import java.net.* ;
public class Server {
int port;
private final static int PACKETSIZE = 100 ;
private boolean isStopped = false;
public Server(){
}
public Server(int port) {
this.port = port;
}
public void stop() {
this.isStopped = true;
}
public void start() {
try
{
DatagramSocket socket = new DatagramSocket(this.port) ;
System.out.println( "Serwer gotowy..." ) ;
if(!this.isStopped){
for( ;; ){
DatagramPacket packet = new DatagramPacket( new byte[PACKETSIZE], PACKETSIZE ) ;
socket.receive( packet ) ;
System.out.println( packet.getAddress() + " " + packet.getPort() + ": " + new String(packet.getData()) ) ;
socket.send( packet ) ;
}
}
}
catch( Exception e )
{
System.out.println( e ) ;
}
}
}
And class from first server to receive :
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
public class ReceiverThread extends Thread {
private DatagramSocket udpClientSocket;
private boolean stopped = false;
public ReceiverThread(DatagramSocket ds) throws SocketException {
this.udpClientSocket = ds;
}
public void halt() {
this.stopped = true;
}
public void run() {
byte[] receiveData = new byte[1024];
while (true) {
if (stopped)
return;
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
try {
udpClientSocket.receive(receivePacket);
String serverReply = new String(receivePacket.getData(), 0, receivePacket.getLength());
System.out.println("UDPClient: Response from Server: \"" + serverReply + "\"\n");
Thread.yield();
}
catch (IOException ex) {
System.err.println(ex);
}
}
}
}
Second class from first server to send messages :
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
public class ReceiverThread extends Thread {
private DatagramSocket udpClientSocket;
private boolean stopped = false;
public ReceiverThread(DatagramSocket ds) throws SocketException {
this.udpClientSocket = ds;
}
public void halt() {
this.stopped = true;
}
public void run() {
byte[] receiveData = new byte[1024];
while (true) {
if (stopped)
return;
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
try {
udpClientSocket.receive(receivePacket);
String serverReply = new String(receivePacket.getData(), 0, receivePacket.getLength());
System.out.println("UDPClient: Response from Server: \"" + serverReply + "\"\n");
Thread.yield();
}
catch (IOException ex) {
System.err.println(ex);
}
}
}
}
And server PKI :
public class ServerPKI {
}
Whenever I run my Chat Server it works until the client connects and then I get a Null Pointer exception at
connections.add(socket);
which crashes it and then this happens every time I run it.
I know my client side is fine because I watched a tutorial a few months ago on how to do this and that server works with my client without crashing
private static ServerSocket server;
private static Socket socket;
private static Scanner input;
private static PrintWriter output;
private static final int port = 444;
private static String message;
private static ArrayList<Socket> connections;
private static Server serverClass;
public Server() {
message = "";
connections = new ArrayList<Socket>();
serverClass = new Server();
}
public void run() {
try {
try {
input = new Scanner(socket.getInputStream());
output = new PrintWriter(socket.getOutputStream());
while(true) {
checkConnection();
if(!input.hasNext()) {
return;
}
message = input.nextLine();
System.out.println("Client said: " + message);
for(int i = 1; i <= connections.size(); i++) {
Socket tempSock = (Socket) connections.get(i - 1);
output.println(message);
output.flush();
}
}
}
finally {
socket.close();
}
}
catch(Exception e) {
System.out.print(e);
}
}
public void checkConnection() throws IOException {
if(!socket.isConnected()) {
for(int i = 1; i <= connections.size(); i++) {
if(connections.get(i) == socket) {
connections.remove(i);
}
}
for(int i = 1; i <= connections.size(); i++) {
Socket disconnectedUser = (Socket) connections.get(i - 1);
System.out.println(disconnectedUser + " has Disconnected!");
}
}
}
public static void main(String[] args) throws IOException{
try {
server = new ServerSocket(port);
System.out.println("Waiting for Clients... ");
while(true) {
socket = server.accept();
connections.add(socket);
System.out.println("Client connected from: " + socket.getLocalAddress().getHostName());
Thread thread = new Thread(serverClass);
thread.start();
}
}
catch(Exception e) {
e.printStackTrace();
}
}
If you get an NPE at connections.add(socket), it can only be because connections is null. Which it is, because you haven't constructed an instance of Server: instead you are trying to execute all its code from main(). The only place you call new Server() from is inside the constructor for Server, which you have clearly never executed at all, as you would have got a StackOverflowError from the infinite recursion.
This code is a real mess:
fix the infinite recursion
construct an instance of Server in your main() method
make connections non-static
make socket a local variable in the accept loop
fix your loops to iterate from 0 to connections.size()-1
and try again.
How do I make this program exit when I run it in terminal using the Java JDK in Ubuntu?
I want to type in "end" when this program is running, but I can't get it to work.
It listens for clients and calls a thread thingy to create a socket for the new client.
I can't figure out how to make this program end. I tried everything.
I started learning java yesterday.
Please help me....
import java.net.*; //jave lib
import java.io.*; //io lib
public class MultiServerConnections { //initiate class
public static void main(String[] args) throws IOException {
int portNum = 5342; //set server port number
boolean listen = true;
System.out.println("Listening for Connections"); //print message
ServerSocket server_Socket = null; //set server_Socket to null
try {
server_Socket = new ServerSocket(portNum); //set server port
} catch (IOException e) {
System.err.println("Port " + portNum + " is unavailable"); //port is taken error
System.exit(1);
}
BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in)); //set reader
String input;
//while (TCPglobals.checkRequests){
while (listen == true){
new MultiServer(server_Socket.accept()).start();
input = stdIn.readLine();
//if(TCPglobals.checkRequests == false) //|| (input = stdIn.readLine()) == "end")
if(input == "end") {
System.out.println("end connection?");
System.exit(1);
}
}//while
server_Socket.close(); //close server socket
}
}
I have a java applet recently stopped working after the server is updated, more specifically:
1. The server is updated from Sun, running Solaris 9, 32 bit. (installed in 2005) to CentOS 5, (linux) on 64 bit.
2. The applet has two major classes 1) collect.class: collects data from a canvas 2) server.class: listens to collect.class through a PORT and acts accordingly;
but the applet got stuck and I check the start_server.sh (which produces a report nohup.out) there is a line
Exception creating server socket: java.net.BindException: Address already in use
This is weird, because PORT = 9999 which collect.class uses with no problem. How comes the problem happens only in server.class (who listens to collet.class).
Please help!
ADDITIONAL INFORMATION:
I.IN COLLECT.JAVA:
There is a canvas with grid on it, the user draw some area on the grid and click "Submit".
-> The MineCanvas.submit() is triggered -> The value of the area is computed by MineCanvas.ComputeGridValue() -> then Collect.cleintSend (stuck here)
import java.applet.*;
import java.awt.*;
import java.net.*;
import java.io.*;
import java.util.*;
public class Collect extends Applet {
...
public static final int PORT = 8888;
...
public boolean action(Event e, Object arg) {
...
if (arg.equals("Submit")) {
if (action(null, "Update Grid")) {
minecanvas.Submit();
} else {
return true;
}
}
return true;
}
...
public void clientSend(){
s = new Socket(this.getCodeBase().getHost(), PORT);
in = new DataInputStream(s.getInputStream());}
out = new DataOutputStream(s.getOutputStream());
listener = new SolutionListener(in, minecanvas);}
minecanvas.mode = MineCanvas.SUBMITTING;
minecanvas.repaint();
int n = 1;
out.writeBytes(minecanvas.gridh + "\n" + minecanvas.gridw + "\n");
for (int h = 0; h < minecanvas.gridh; h++) {
for (int w = 0; w < minecanvas.gridw; w++) {
out.writeBytes(n + " " + minecanvas.AllCells[w][h].net + "\n");
n++;
}
}
out.writeBytes("done\n");
s = null;
in = null;
out = null;
}
}
class MineCanvas extends Canvas {
...
public int gridw = 0; // number of grid squares width-ly
public int gridh = 0; // number of grid squares height-ly
public GridCell[][] AllCells; // array of grid cells comprising the grid
...
// compute values for minecanvas
public void ComputeGridValue() {...}
public void Submit() {
ComputeGridValue();
parent.clientSend();
}
...
}
...
}
II. SERVER.JAVA
import java.io.*;
import java.net.*;
public class Server extends Thread {
private OPM_Server opm; // this is the corresponding server for collect
...
public Server() {
...
opm = new OPM_Server();
}
public static void main(String[] args) {
new Server();
}
}
...
// OPM: correspond to Collect
class OPM_Server extends Thread {
public final static int DEFAULT_PORT = 8888;
protected int port;
protected ServerSocket listen_socket;
public static void fail(Exception e, String msg) {
System.err.println(msg + ": " + e);
System.exit(1);
}
public OPM_Server() {
this.port = DEFAULT_PORT;
try { listen_socket = new ServerSocket(port); }
catch (IOException e){ fail(e, "Exception creating server socket");}
System.out.println("Server: listening on port " + port);
this.start();
}
public void run() {
try {
while(true) {
System.out.println("I got to before ServerSocket");
Socket client_socket = listen_socket.accept();
OPM_Connection c = new OPM_Connection(client_socket);
}
}
catch (IOException e) {fail(e, "Exception while listening for connections");}
}
}
...
class OPM_Connection extends Thread {
protected Socket client;
protected BufferedReader in;
protected DataOutputStream out;
File mine_data = new File("mine_data"); // output file data
FileOutputStream file_stream;
DataOutputStream file_out;
public OPM_Connection(Socket client_socket) {
client = client_socket;
try {
in = new BufferedReader(new InputStreamReader(client.getInputStream()));
out = new DataOutputStream(client.getOutputStream());
} catch (IOException e) {
try {
client.close();
} catch (IOException e2) {
}
;
System.err.println("Exception while getting socket stream: "
+ e.toString());
return;
}
this.start();
}
public void run() {
...
file_stream = new FileOutputStream(mine_data);
file_out = new DataOutputStream(file_stream);
...// write to mine data
file_out = null;
if (inputGood == true) {
System.out.println(pid + "> ---Got all info from client");
Runtime r = Runtime.getRuntime();
Process Aproc = null;
Process Bproc = null;
int returnVal = -1;
try {
Aproc = r.exec("runOPM");
} catch (IOException e) {
inputGood = false;
System.out.println(pid + "> runOPM didn't exec");
}
try {
returnVal = Aproc.waitFor();
} catch (InterruptedException e) {
inputGood = false;
System.out.println(pid + "> runOPM didn't return");
}
System.out.println(pid + "> ---All execing done");
File report = new File("mine_report");
FileInputStream report_stream = null;
...
// create a mine report
System.out.println(pid + "> ---Done sending data back to client");
}
try {
client.close();
} catch (IOException e2) {
}
;
System.out.println(pid + "> EXITING THREAD");
}
}
Exception creating server socket: java.net.BindException: Address
already in use
This exception means that the port number the socket is trying to bind to (the port number your socket is trying to use in the local-end of the connection) is already in use by some other program. To fix it, you either need to find out what other software is using the port and see if you can safely change it, or change the port your program is using.
Edit: It might be worth trying to look for rarely used port(s), to lessen the chance of using yet another port that is known to be used by some common software, here's Wikipedias list of typical TCP and UDP ports in use by common programs and services.