Java网络中的EOFException

Question

it is my first time using java networking. I have to use it for a project i am working on which is a simple card game. My server and client will communicate as the "Connection Received" does get printed. But after this line the following error occurs:

java.io.EOFException
at java.io.ObjectInputStream$BlockDataInputStream.peekByte(Unknown Source)
at java.io.ObjectInputStream.readObject0(Unknown Source)
at java.io.ObjectInputStream.readObject(Unknown Source)
at ClientConnectionManager.reciveData(ClientConnectionManager.java:49)
at LogicThread.getHandSize(GameLogic.java:22)
at LogicThread.run(GameLogic.java:16)
at java.lang.Thread.run(Unknown Source)
Exception in thread "Thread-4" java.lang.NullPointerException
at LogicThread.getHandSize(GameLogic.java:22)
at LogicThread.run(GameLogic.java:16)
at java.lang.Thread.run(Unknown Source)

the classes in question are:

static ObjectInputStream input;
static ObjectOutputStream output;
static Socket socket;

    public static void connectToServer(){
    try {
        System.out.println("connecting");
        socket = new Socket(ip, port);
        input = new ObjectInputStream(socket.getInputStream());
        output = new ObjectOutputStream(socket.getOutputStream());
        output.flush();
        System.out.println("connected");
        reciveData();
        logic.startLogic();
        //listenForData();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public static Object reciveData(){
    try {
        Object obj = input.readObject(); - Error is on this line
        System.out.println(obj);
        return obj;
    } catch (ClassNotFoundException | IOException e) {
        e.printStackTrace();
    }
    return null;
}

The server code for sending data:

    ServerSocket server;
    server = new ServerSocket(2302);
    Socket connection;
    connection = server.accept();
    output = new ObjectOutputStream(connection.getOutputStream());

    public void sendData(Object data){
    try {
        output.writeObject(data);
        output.flush();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

I am not sure what causes this because the server sends a "Connection Received" which the client receives with no issue and prints. But any call from outside the connectToServer() Method cause the error above.

Answer 1

The peer has closed the connection. Somewhere the server is closing the accepted socket or one of its streams.

That implies that if the server has really called sendData() it must have thrown an exception you haven't mentioned.