为什么 BufferedWriter 不会从客户端写入服务器？

Question

我正在使用线程构建客户端-服务器应用程序，但由于某种原因，BufferedWriter 不会通过套接字将数据发送到客户端。 运行客户端后，我还收到了Socket Exception: Connection Reset。 我错过了什么？ 服务器：

public class Servernew {

protected String username;

protected ServerSocket serverSocket;

protected static LinkedList<ClientThreadNew> clients;

public static LinkedList<ClientThreadNew> getClients() {
    return clients;
}

public Servernew(int port) {
    try {

        serverSocket = new ServerSocket(port);

        clients = new LinkedList<ClientThreadNew>();
        System.out.println("Server is now running on port " + port);

        while (true) {

            Socket clientSocket = serverSocket.accept();

            ClientThreadNew clientThread = new ClientThreadNew(
                    clientSocket, username);

            clients.addLast(clientThread);

            clientThread.start();



        }

    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public static void main(String[] args) { 

    new Servernew(4444);
}

}

客户端线程：

public class ClientThreadNew extends Thread implements Runnable {

protected String username;

public String getUsername() {
    return username;
}

public void setUsername(String username) {
    this.username = username;
}

protected Socket clientSocket;

protected BufferedReader inFromClientB;




protected BufferedWriter outToClient;




public ClientThreadNew(Socket clientSocket, String username)
        throws IOException {

    this.clientSocket = clientSocket;
    this.username = username;



    inFromClientB = new BufferedReader(new InputStreamReader(
            clientSocket.getInputStream()));



    outToClient = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));

}

public void run() {


    try {

        while (true) {



            String incomingMessage = inFromClientB.readLine();

            if (incomingMessage != null) {


                setUsername(incomingMessage);


                outToClient.write("hii");
                outToClient.newLine();
                outToClient.flush();




            }

        }
    } catch (IOException e) {
        System.out.print(e);

    }

}

}

客户端测试：

public class ClientTesst {
private static Socket socket;
private static BufferedWriter outToServer;
private String hostname;
private int portnum;
private static BufferedReader inFromServer;

public ClientTesst(String hostname, int portnum) throws IOException {
    this.hostname = hostname;
    this.portnum = portnum;

}

public void connect() throws UnknownHostException, IOException {

    socket = new Socket(hostname, portnum);
    System.out.println("Connection Established");
}

public String listUsers() throws IOException {

    inFromServer = new BufferedReader(new InputStreamReader(
            socket.getInputStream()));
    String listOfUsers = inFromServer.readLine().toString();

    return (listOfUsers);
}

public void sendMessage(String Msg) throws IOException {



    outToServer = new BufferedWriter(new OutputStreamWriter(
            socket.getOutputStream()));
    outToServer.write(Msg);
    outToServer.newLine();
    outToServer.flush();

}

public static void main(String[] args) throws Exception {

    ClientTesst x = new ClientTesst("localhost", 4444);
    x.connect();
    x.sendMessage("client x");

    ClientTesst y = new ClientTesst("localhost", 4444);
    y.connect();
    y.sendMessage("client y");
    y.listUsers();



}

}

Answer 1

在你的ClientTesst 班级你有这个：

private static Socket socket;
private static BufferedReader inFromServer;
private static BufferedWriter outToServer; 

由于所有这些变量都是static，这意味着两个客户端x 和y 将使用相同的socket、outToServer 和inFromServer。

将此变量设为实例变量（通过删除static），以便ClientTesst 的每个实例都有其在套接字和流上。

Answer 2

以下作品-

    class ClientThreadNew extends Thread implements Runnable {   

        protected String username;
        protected Socket clientSocket;
        protected BufferedReader inFromClientB;
        protected BufferedWriter outToClient;

        public String getUsername() {
            return username;
        }

        public void setUsername(String username) {
            this.username = username;
        }

        public ClientThreadNew(Socket clientSocket, String username) throws IOException {
            this.clientSocket = clientSocket;
            this.username = username;
        }

        public void run() {
            try {
                outToClient = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));
                inFromClientB = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
                String incomingMessage, outgoingMessage;
                while ((incomingMessage = inFromClientB.readLine()) != null) {
                    setUsername(incomingMessage);
                    System.out.println("From client: " + incomingMessage);
                    outgoingMessage = "hii";
                    Thread.sleep(2000);
                    outToClient.write(outgoingMessage);
                    outToClient.newLine();
                    outToClient.flush();
                    System.out.println("From server: " + outgoingMessage);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

public class ClientTest {
    private Socket socket;
    private BufferedReader inFromServer;
    private BufferedWriter outToServer;
    private String hostname;
    private int portnum;

    public ClientTest(String hostname, int portnum) throws IOException {
        this.hostname = hostname;
        this.portnum = portnum;
    }    

    public void connect() throws IOException {
        socket = new Socket(hostname, portnum);
        outToServer = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
        inFromServer = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        System.out.println("Connection Established");
    }

    public String listUsers() throws IOException {
        return inFromServer.readLine();
    }

    public void sendMessage(String Msg) throws IOException {
        outToServer.write(Msg);
        outToServer.newLine();
        outToServer.flush();
    }    

    public static void main(String[] args) throws Exception {
        ClientTest x = new ClientTest("localhost", 4444);
        x.connect();
        x.sendMessage("client x");
        String messageFromServer;
        while ((messageFromServer = x.listUsers()) != null) {
            System.out.println("From server: " + messageFromServer);
            Thread.sleep(2000);
            x.sendMessage("client x");
            System.out.println("From client: client x");
        }
    }
}