Java从套接字读取消息未发送完整消息

Question

hello I am using this method to read a message:

public String readMessage() {
    int read = -1;
    byte[] buffer = new byte[5*1024];
    byte[] redData;
    try {
        while ((read = this.session.getInputStream().read(buffer)) > -1) {
            redData = new byte[read];
            System.arraycopy(buffer, 0, redData, 0, read);
            return new String(redData,"UTF-8");

        }
    } catch (IOException e) {
        e.printStackTrace();
    }
    return null;
}

And when I write something like "hello how are you today?"

Response (Exact format, including these new lines):

[/127.0.0.1:54930]:     
[/127.0.0.1:54930]: are

[/127.0.0.1:54930]: you

[/127.0.0.1:54930]: today?

Thats how I read chat messages, first I check which packet was requested, if the packet type was 0, then I get instance of packethandler, and pass the client object to the Chat handling packet which will read the message here, like this:

public void startClientService() throws IOException {
    while(true) {
        int packetType = this.in.read();
        packets.getPacket(packetType);
    }
}
public void getPacket(int packetType) {
    switch (packetType) {
    case 0:
        chat.processPacket(this.client);
        break;
    }
}

And the chat packet:

@Override
public void processPacket(Session c) {
    String clientMessage = c.readMessage();
    System.out.println("[" + c.getStream().getRemoteSocketAddress() + "]: " + clientMessage.toString());
}

And there the print message happens.

Why does it print parts of the messages, in new lines? not even the full message.

This is my client:

public static void main(String[] args) throws UnknownHostException, IOException {
    Socket socket = new Socket("127.0.0.1", 43594);
    Scanner r = new Scanner(System.in);
    PrintWriter out = new PrintWriter(socket.getOutputStream());
    String input;
    while(true) {
        input = r.next();
        if (input != null) {
            sendMessage(input, out);
        }
    }

}

public static void sendMessage(String message, PrintWriter out) {
    out.write(0);
    out.flush();
    out.write(message + "\n");
    out.flush();
}

Thanks.

Session:

public class Session extends Thread implements Runnable {

    private Socket session;
    private Client client;
    private PrintWriter out;
    private BufferedReader in;  
    private PacketHandler packets;

    public Session(Socket session) {
        this.session = session;
        this.client = new Client(this);
        try {
            this.setStream();
        } catch (IOException e) {
            e.printStackTrace();
        }
        this.packets = new PacketHandler(this);
        System.out.println("[New session created]: " + session.getRemoteSocketAddress());
    }   

    public void run() {
        try {
            this.startClientService();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public Socket getStream() {
        return this.session;
    }

    public void setStream() throws IOException {
        this.out = new PrintWriter(this.session.getOutputStream());
        this.in = new BufferedReader(new InputStreamReader(this.session.getInputStream()));
    }

    public Client getClient() {
        return this.client;
    }

    public String readMessage() {
        int read = -1;
        byte[] buffer = new byte[5*1024];
        byte[] redData;
        try {
            while ((read = this.session.getInputStream().read(buffer)) > -1) {
                redData = new byte[read];
                System.arraycopy(buffer, 0, redData, 0, read);
                return new String(redData,"UTF-8");

            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    public void startClientService() throws IOException {
        while(true) {
            int packetType = this.in.read();
            packets.getPacket(packetType);
        }
    }

    public void destruct() throws IOException {
        this.session.close();
        System.out.println("Session killed");
    }

}

Answer 1

looks like you are returning as soon as you get some data from stream.

  while ((read = this.session.getInputStream().read(buffer)) > -1) {
            redData = new byte[read];
            System.arraycopy(buffer, 0, redData, 0, read);
            return new String(redData,"UTF-8");

        }

Read the data completely and make a string object out of it and return it

    BufferedReader br = new BufferedReader(new InputStreamReader(this.session.getInputStream()));
String msg = br.readLine();
br.close();
    return msg;

try this way. This will give you entire data to a buffer and can return as line of string.No need of loop

Answer 2

The the amount of data returned from one call to read has no relationship to how the data divided when sent. One send can result in any number of reads, and multiple sends may be combined into one read.