java TCP socket message breaks

i have a java client-server app in java, both using the same connection class that contains both send/receive messages. for some reason, some of the messages i send are received in a malformed order:

here's the code

//set up
_in = new BufferedReader(new InputStreamReader(this._socket.getInputStream()));
_out = new BufferedWriter(new OutputStreamWriter(this._socket.getOutputStream()));
this._socket.setSoTimeout(S_TIMEOUT);


public synchronized boolean send(String message){
    try {
        _out.write(message);
        _out.write(Connection.DELIMITER);
        _out.flush();
        return true;
    } catch (IOException e) {
    }
    return false;
}


public String receive(){
    int c;
    try {
        String message = "";
        System.out.println("Getting message:");
        c = _in.read();
        while(c != -1 && c != Connection.DELIMITER) {
            message += (char) c;
            c = _in.read();
        }
        if (c == -1) {
            return null;
        }
        return message;
    } catch (IOException e) { }
    return null;
}

some messages, for example "new_order" will might return with "ew_ord". some characters are lost, others are sent separately. this seems odd as its TCP

could this be an encoding related issue?

Delimiter is (char) 0 socket timeout is 20000 (ie 20 senconds). every 10 seconds i send an empty message to make sure socket does not close

EDIT: although it was solved using the Scanner, i must say that the original code worked fine for many messages/various machines for a very long time (a few weeks), and then suddenly failed to work with one specific message on one specific machine (other messages went through just fine). i've done socket data transfer in java MANY times and i've written many read/write methods to handle the sockets. it's the first time i ran into this.

although in the original code i set the encoding (in the posted code i didn't), i believe that the problem was encoding related. at one point, the message that was received had every second character missing. afterwards i changed it a bit, and the first/second character of the message were received in a separate message. from my understanding, it's either an encoding issue or some firewall/other security program that was running on the message sender mach开发者_运维百科ine, that decided to filter outgoing packets.

---

Try replacing your receive with a Scanner and let it do the work for you.

// in your setup
Scanner sc = new Scanner(_in).useDelimiter(Connection.DELIMETER);

public String receive() {
    try {
        return sc.next();
    } catch(IOException e) {
        return "";
    }

}

---

For starters, I would make sure you're printing exceptions in those catch blocks.

Then, you're using the platform default encoding for converting characters to bytes. If these two processes are running on different machines, it's possible they're using different encodings. I would make sure you're specifying an encoding when you set up the Reader and Writer.

---

You can use UTF encoding for getting Full String of Message.

U can try this code and I am Sure About this code because i used it in My Chat Application.

String data=" ";

socket = new Socket("localhost",999);
while(true)
        {
           dos = new DataOutputStream(socket.getOutputStream());
           dis =  new DataInputStream(socket.getInputStream());
           data = dis.readUTF();
           jta.append(data +"\n");
        }

Where jta is JTextArea.

It's for Client Side

Now For Server Side:

try
{

server = new ServerSocket(999);     

Socket  soc = server.accept();  

        while(true)
        {
            String data="";
            try
            {                   
                dis = new DataInputStream(soc.getInputStream());
                dos = new DataOutputStream(soc.getOutputStream());
                data = dis.readUTF();
            }
            catch(Exception e)
            { }
            jta.append(data + "\n");
        }
    }
    catch (IOException e) 
    {
        JOptionPane.showMessageDialog(this, e);
        System.exit(-1);
    }