Java套接字编程问题（发送和接收数据）

Question

Client has sendpoints() method which is called by some other class that I did not include. Anyways, sendpoints() is called and sends integers to the server, which receives them and send back to all the clients that are connected to the server(broadcast).

The problem is, clients keep sending integers while server is stuck in the thread I created for receiving integers(I think the server is not reading from inputstream).

I tried changing the stream, I tried putting integers together in a object and send it with ObjectOutputStream but none of these seems to work. I need help (pointStruct is a class that holds some integer values I created)

import java.net.*;
import java.util.*;
import java.awt.*;
import java.io.*;
import javax.swing.*;



public class Server {


    private ArrayList dataclient;
    private ArrayList messageclient;

    private ServerSocket dataserver;
    private ServerSocket messageserver;

    public static void main(String[] args) {
        Server s1 = new Server();
        s1.start();

    }

    // Start running server
    public void start() {
        try {
            dataserver = new ServerSocket(4999);
            messageserver = new ServerSocket(5000);
            Socket dataconn;
            Socket messageconn;

            dataclient = new ArrayList();
            messageclient = new ArrayList();
            dataconn= null;
            messageconn= null;
            System.out.println("[server]start");

            //start accepting connections
            while (true) {
                try {
                dataconn = dataserver.accept();
                System.out.println("[server]accepted dataconn");

                messageconn = messageserver.accept();
                System.out.println("[server]accepted messageconn");

                //add clients to arraylist

                dataclient.add(dataconn.getOutputStream());

                messageclient.add(messageconn.getOutputStream());

                }
                catch (Exception ex) {
                    ex.printStackTrace();
                }

                //creating receiver threads
                Thread t1 = new Thread(new DataReceiver(dataconn));
                Thread t2 = new Thread(new MessageReceiver(messageconn));
                System.out.println("[server]Thread successfully created");
                t1.start();
                t2.start();
                System.out.println("[server]Thread successfully started");
            }
        }
        catch(Exception ex) {
            ex.printStackTrace();
        }
    }

    //receive data from clients
    public class DataReceiver implements Runnable {

        BufferedReader br;
        InputStream is;

        int x,y;
        int x2,y2;
        int t;
        int red;
        int green;
        int blue;
        int size;
        int dummy;

        DataReceiver(Socket s){
            try {
                is=s.getInputStream();
                //br = new BufferedReader(isr);
            }
            catch(Exception ex) {
                ex.printStackTrace();
            }
        }
        public void run() {
        while(true) {
            try{

                Iterator it = dataclient.iterator();
                dummy=is.read();
                if(dummy==9999) {
                System.out.println("[server]executing data thread");
                x=is.read();
                System.out.println("[server]read a line"+x);
                y=is.read();
                System.out.println("[server]read a line"+y);

                //x2=isr.read();
                //y2=isr.read();
                t=is.read();
                red=is.read();
                green=is.read();
                blue=is.read();
                size=is.read();

                dummy=0;
                //broadcast data

                while (it.hasNext()) {
                    OutputStream os = (OutputStream)it.next();
                    os.write(9999);
                    os.write(x);
                    os.write(y);
                    os.write(t);
                    os.write(255);
                    os.write(0);
                    os.write(0);
                    os.write(size);
                }
                System.out.println("[server]data broadcasted");
                }
            }
            catch(Exception ex) {
                ex.printStackTrace();
            }


    }
    }   
    }

    //------------------------receive message from clients------------------------
    public class MessageReceiver implements Runnable {

        MessageReceiver(Socket s) {

        }

        public void run() {


        }

    }
}




public class networkHandler{
    PrintWriter writer;
    BufferedReader reader;
    PrintWriter pwriter;
    BufferedReader preader;
    Socket sock;
    Socket pointsock;
    InputStream is;
    JTextArea incoming;
    pointHandler ph;

    public networkHandler(pointHandler _ph) {
        init();
        ph=_ph;
        setUpNetworking();
        Thread readerThread = new Thread(new IncomingReader());
        readerThread.start();
        Thread pointerThread = new Thread(new ReceivingPoints());
        pointerThread.start();
    }

    public void init() {
        incoming = new JTextArea(20,20);
    }
    private void setUpNetworking() {
        try {

            // setup message port
            System.out.println("networking establish started");
            sock = new Socket("127.0.0.1",5000);
            System.out.println("[NH]port 5000 established");

            // setup point port
            pointsock = new Socket("127.0.0.1",4999);
            System.out.println("[NH]port 4999 established");

            //message i/o stream
            InputStreamReader streamReader = new InputStreamReader(sock.getInputStream());
            reader = new BufferedReader(streamReader);
            writer = new PrintWriter(sock.getOutputStream());


            //point i/o stream
            InputStreamReader pstreamReader = new InputStreamReader(pointsock.getInputStream());
            System.out.println("networking establishing: Stream");
            preader= new BufferedReader(pstreamReader); 
            pwriter= new PrintWriter(pointsock.getOutputStream());
            System.out.println("networking establishing: Stream");
        }
        catch(IOException ex) {
            ex.printStackTrace();
        }
        System.out.println("networking established");
    }

    //send message to the server
    public void writeStream(String input){
        try {
            writer.println(input);

            writer.flush();     
        }
        catch(Exception ex) {
            ex.printStackTrace();
        }
    }
    public JTextArea getServerMessage() {
        return incoming;
    }

    //receiving message from server
    public class IncomingReader implements Runnable {

        @Override
        public void run() {
            String message;
            try {
                while ((message = reader.readLine())!=null){
                    System.out.println("[NH] read from server:"+message);
                    incoming.append(message+"\n");
                }
            }
            catch(Exception ex) {
                ex.printStackTrace();
            }

        }

    }

    //receiving points from server
    public class ReceivingPoints implements Runnable {

        int x,y;
        int x2,y2;
        int red;
        int green;
        int blue;
        int t;
        int size;
        int dummy;
        pointStruct ps;
        Color cr;
        Point p;

        synchronized public void run() {
            try {
                is = pointsock.getInputStream();
                p= new Point();
            }
            catch(Exception ex) {
                ex.printStackTrace();
            }

            while(true) {
                try {
                dummy=is.read();
                if(dummy==9999) {

                x=is.read();
                y=is.read();

                //x2=preader.read();
                //y2=preader.read();

                t=is.read();
                red=is.read();
                green=is.read();
                blue =is.read();
                size=is.read();






                //create dummy pointStruct  
                ps = new pointStruct();
                cr = new Color(red,green,blue);

                p.x=x;
                p.y=y;
                ps.setP1(p);
                p.x=x2;
                p.y=y2;
                //ps.setP2(p);
                ps.setT((char)t);
                ps.setS(size);
                ps.setC(cr);

                ph.save(ps);
                dummy=0;
                }

                }   
                catch(Exception ex) {
                ex.printStackTrace();
                }

            System.out.println("[NH]receiving done");
            }
    }}


    public void sendPoints(pointStruct ps) {        
        OutputStream os;
        try{
            os=pointsock.getOutputStream();
            os.write(9999);
            os.write(ps.getP1().x);
            os.write(ps.getP1().y);
            //pwriter.print(ps.getP2().x);
            //pwriter.print(ps.getP2().y);

            os.write(ps.getT());
            os.write(ps.getC().getRed());
            os.write(ps.getC().getGreen());
            os.write(ps.getC().getBlue());
            os.write(ps.getS());
        }
        catch(Exception ex) {
            ex.printStackTrace();
        }
        System.out.println("[NH]points sent to server");
    }       
}

Answer 1

You are reading the stream incorrectly, InputStream.read() returns a byte from the stream, but cast to an int.

InputStream.read() returns values from 0 to 255 is read is successful, and -1 if no more reading can be done (end of stream).

For example, InputStream.read() != 9999 always. So this ReceivingPoints.run() block will not fire:

while (true) {
    try {
        dummy = is.read();
        if (dummy == 9999) {}
    } catch(Exception ex) {
        ex.printStackTrace();
    }
}

You are looking for DataInputStream , it has methods for reading and writing other basic types than just bytes.