Question

我创建了一个serverSocket并接受客户端连接。但是，当我尝试从客户端读取时，它抛出以下异常。如果我将HashMap更改为ArrayList，则它也无效。

Exception in thread "Thread-3" java.lang.ClassCastException: java.awt.Point cannot be cast to java.util.HashMap
at ServerSide.Server.getPoints(Server.java:112)
at ServerSide.Server.run(Server.java:69)

public void getPoints() throws IOException, ClassNotFoundException {
    points = (HashMap<Point, Boolean>) objectInputStream.readObject();
    Iterator iterator = points.entrySet().iterator();
    while (iterator.hasNext()) {
        Map.Entry<Point, Boolean> currentPoint = (Map.Entry<Point, Boolean>) iterator.next();
        currentPoint.setValue(firgure.isHit(currentPoint.getKey().x, currentPoint.getKey().y));
    }
    objectOutputStream.writeObject(points);
}

发送方式：

@Override
public HashMap<Point, Boolean> update(HashMap<Point, Boolean> points) throws IOException {
    output.println("hit");
    output.flush();
    toServer.writeObject(points);
    try {
        return (HashMap<Point, Boolean>) fromServer.readObject();
    } catch (ClassNotFoundException e) {
        System.out.println("Some shit with classCast!");
        return null;
    }
}

UDP新类型例外：

java.io.StreamCorruptedException: invalid type code: 3F
  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1377)
  at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371)
  at ServerSide.Server.getPoints(Server.java:102)
  at ServerSide.Server.run(Server.java:69)

此视频展示了它（不）的工作方式： http://www.youtube.com/watch?v=8924rrSyWfY&feature=youtu.be

也许我的服务器或客户端不好？谁能看到一些错误？（我很抱歉我的英语）

服务器

public class Server extends Thread {
    public static final int PORT = 1234;
    private static ServerSocket serverSocket;
    private Socket client;
    private ObjectInputStream objectInputStream;
    private ObjectOutputStream objectOutputStream;
    private BufferedReader bufferedReader;
    private PrintWriter printWriter;
    private Firgure firgure;
    private HashMap<Point, Boolean> points;


    private Server(Socket client) {
        System.out.println("Client connected");
        this.client = client;
        firgure = new Firgure();
        try {
            this.client.setSoTimeout(0);
        } catch (SocketException e) {
            e.printStackTrace();
        }
        setDaemon(true);
        setPriority(NORM_PRIORITY);
        start();
    }

    static public void serverStart() throws IOException {
        System.out.println("Server startes");
        serverSocket = new ServerSocket(PORT);
        serverSocket.setSoTimeout(0);
        System.out.println("Wait client");
        while (true) new Server(serverSocket.accept());
    }

    static public void main(String[] args) throws IOException {
        serverStart();
    }

    @Override
    public void run() {
        try {
            objectInputStream = new ObjectInputStream(client.getInputStream());
            objectOutputStream = new ObjectOutputStream(client.getOutputStream());
            bufferedReader = new BufferedReader(new InputStreamReader(client.getInputStream()));
            printWriter = new PrintWriter(client.getOutputStream(), true);
            points = new HashMap<Point, Boolean>();
            String inputLine;

            do {
                inputLine = bufferedReader.readLine();
                if (inputLine.equalsIgnoreCase("hit")) getPoints();
                else if (inputLine.equalsIgnoreCase("echo")) echo();
                else if (inputLine.equalsIgnoreCase("close")) close();
                else if (inputLine.equalsIgnoreCase("set")) set();
                else if (inputLine.equalsIgnoreCase("get")) get();
                else continue;
            } while (true);
        } catch (NullPointerException e) {
            System.out.println("Client disconnect");
        } catch (IOException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        } catch (java.lang.ClassNotFoundException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        }
    }

    public int getR() {
        return firgure.getR();
    }

    public void setR(int R) {
        firgure.setR(R);
    }

    public void set() throws IOException, ClassNotFoundException {
        setR((Integer) objectInputStream.readObject());
    }

    public void get() throws IOException {
        objectOutputStream.writeObject(new Integer(getR()));
    }

    public void getPoints() throws IOException, ClassNotFoundException {
        try {
            points = (HashMap<Point, Boolean>) objectInputStream.readObject();
        } catch (StreamCorruptedException e) {
            e.printStackTrace();
            points = new HashMap<Point, Boolean>();
        } catch (ClassCastException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }

        Iterator iterator = points.entrySet().iterator();
        while (iterator.hasNext()) {
            Map.Entry<Point, Boolean> currentPoint = (Map.Entry<Point, Boolean>) iterator.next();
            currentPoint.setValue(firgure.isHit(currentPoint.getKey().x, currentPoint.getKey().y));
        }
        objectOutputStream.writeObject(points);
    }

    public void echo() throws IOException {
        printWriter.println(bufferedReader.readLine());
    }

    private void close() {
        try {
            if (objectInputStream != null) objectInputStream.close();
            if (objectOutputStream != null) objectOutputStream.close();
            if (bufferedReader != null) bufferedReader.close();
            if (client != null) client.close();
        } catch (IOException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        }
    }
}

客户端

public class Client implements IModel {
    private static final int PORT = 1234;
    private static final String HOST = "localhost";
    private Socket server;
    private ObjectOutputStream toServer;
    private ObjectInputStream fromServer;
    private BufferedReader input;
    private PrintWriter output;

    @Override
    public HashMap<Point, Boolean> update(HashMap<Point, Boolean> points) throws IOException {
        output.println("hit");
        output.flush();
        toServer.writeObject(points);
        try {
            return (HashMap<Point, Boolean>) fromServer.readObject();
        } catch (ClassNotFoundException e) {
            System.out.println("Some shit with classCast!");
            return null;
        }
    }

    @Override
    public void connect() throws IOException {
        server = new Socket(HOST, PORT);
        toServer = new ObjectOutputStream(server.getOutputStream());
        fromServer = new ObjectInputStream(server.getInputStream());
        input = new BufferedReader(new InputStreamReader(server.getInputStream()));
        output = new PrintWriter(server.getOutputStream(), true);
    }

    @Override
    public void disconnect() throws IOException {
        if (output != null) output.close();
        if (input != null) input.close();
        if (fromServer != null) fromServer.close();
        if (toServer != null) toServer.close();
        if (server != null) server.close();
    }

    @Override
    public boolean isConnected() throws IOException {
        if (server == null) return false;
        return server.isConnected();
    }

    @Override
    public int getFigureRadius() throws IOException {
        output.println("get");
        output.flush();
        try {
            return (Integer) fromServer.readObject();
        } catch (ClassNotFoundException e) {
            System.out.println("Some shit with cast");
            return 0;
        }
    }

    @Override
    public void setFigureRadius(int newRadius) throws IOException {
        output.println("set");
        output.flush();
        toServer.writeObject(newRadius);
    }
}

Answer 1

从您的异常消息中可以清楚地看到这一点。您正在发送一个Point并尝试接收HashMap。

Answer 2

从日志中获得投射错误：

 points = (HashMap<Point, Boolean>) objectInputStream.readObject();

调试试试：

Object obj = objectInputStream.readObject();

if(obj instanceof Map<Point, Boolean>){
 ...
}
else if(obj instanceof String){
 ...
}

套接字ClassCastException HashMap

2 个答案: