Question

我正在制作聊天程序。在连接阶段出现问题。从理论上讲，连接就是这样发生的：

[服务器] accept（）传入连接
[客户端]尝试连接服务器
[服务器＆amp;客户端]初始化IO
[客户]发送带有后缀的用户名，表示
[服务器]接收用户名，检查是否有传入密码（如果有，也可以阅读）
[服务器]检查数据库是否已注册客户
[服务器] ...（对客户的帐户进行多次检查等）
[服务器]如果被接受，则向客户发送答案
[客户]收到答案并解释

请注意，尚未实施步骤6和7，服务器会跳过直接创建新客户帐户并在网络中接受该帐户。

现在，在步骤4中发生了某些事情（如果错误来自客户端没有发送它的名称）或者在步骤5（如果错误来自服务器没有收到名称），则在任何一种情况下，服务器卡在等待客户端的名称，客户端卡住等待服务器的回答（步骤9）。我正在请求您帮助找出此错误的原因以及如何解决此问题。

以下是服务器用于接受新连接的函数的代码：

public void establishConnection() {
    Socket client = null;
    BufferedReader input = null;
    PrintWriter output = null;
    String name = null;
    String password = null;

    try {
        client = server.accept();
        System.out.println("A connection is being established");
        input = new BufferedReader(new InputStreamReader(client.getInputStream()));
        output = new PrintWriter(client.getOutputStream());

        //LOCATION OF THE BUG
        //DESCRIPTION: If the name has been sent, the server seems not to receive it.
        System.out.println("Waiting for the client's name...");
        name = input.readLine();
        if (name.charAt(name.length() - 1) == Keywords.PASSWORD) {
            System.out.println("Waiting for the client's password...");
            password = input.readLine();
        } else
            System.out.println("The client has no password");
        name = name.substring(0, name.length() - 1);

        System.out.println("Creation of the metaClient");
        MetaClient metaClient = new MetaClient(name);
        if (password != null)
            metaClient.setPassword(password);
        metaClient.setSocket(client);
        System.out.println("Activating listening thread");
        metaClient.activateCommunications(this, this);

        /* If there is no already registered clients,
         * the first to connect shall be the owner.
         */
        if (clientsList.size() == 0)
            metaClient.addRight(MetaClient.OWNER);

        clientsList.add(metaClient);

        output.write(Keywords.CONNECTION_ACCEPTED);
        System.out.println("The connection process of user " + metaClient.getName()
                + " is complete.");
    } catch (IOException e) {
        System.out.println("Error when establishing a new connection");
        e.printStackTrace();
    } finally {
        try {
            if (input != null)
                input.close();
            if (output != null)
                output.close();
        } catch (IOException e) {
            System.out.println("Error when closing the IO of the new connection.");
            e.printStackTrace();
        }
    }
}

以下是尝试连接服务器的客户端构建器的代码：

public ChatClient(String ip, int port, String name, String password) throws ConnectException {
    this.name = name;
    boolean connectionRefused = false;
    try {
        System.out.println("Establishing connection to the server...");
        server = new Socket(ip, port);
        BufferedReader input = new BufferedReader(new InputStreamReader(server.getInputStream()));
        PrintWriter output = new PrintWriter(server.getOutputStream());

        //LOCATION OF THE BUG:
        //BUG DESCRIPTION: The name seems not to be sent to the server
        System.out.println("Sending name to the server...");
        if (password == null || password == "") {
            name += Keywords.NO_PASSWORD;
            output.println(name);
        } else {
            name += Keywords.PASSWORD;
            output.println(name);
            System.out.println("Sending password to the server...");
            output.println(password);
        }

        System.out.println("Waiting for the server's response...");
        //Wait for the server's response
        String response = input.readLine();
        if (response.equals(Keywords.CONNECTION_ACCEPTED))
            System.out.println("The connection has been accepted");
        else
            connectionRefused = true;
    } catch (IOException e) {
        System.out.println("Error when connecting to the server");
        e.printStackTrace();
        System.exit(1);
    }

    if (connectionRefused)
        throw new ConnectException("The connection was refused by the server");
    else {
        communication = new CommunicationProtocol(server, this, this);
        communication.start();
    }
}

任何帮助都会非常感激，现在我花了很长时间才试图解决这个问题无济于事。

编辑以回答Scary Wombat的评论：是的，一台机器运行服务器而另一台机器运行客户机。但即使两台计算机在一台计算机上作为两个独立的程序运行，也会发生错误。

服务器未接收数据/客户端未发送数据

0 个答案: