java - 1 台计算机上的客户端服务器错误

Question

我正在编写一个小客户端-服务器应用程序，但遇到以下问题:

我可以毫无问题地启动服务器，但是当我尝试与客户端连接时，它显示连接被拒绝:连接。
谷歌和搜索说我使用了错误的端口，但我在服务器和客户端上使用相同的端口。我在代码中找不到任何错误，也不知道为什么它不起作用。

这是代码:
服务器

public class Server extends JFrame implements Runnable {

    private JPanel contentPane;
    private JTextField textFieldPort;
    private JTextField textFieldMessage;

    private ArrayList<Handler> activeUsers;
    private List listUsers;
    private ServerSocket listen;
    private Thread connect;
    private List listProtocoll;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Server frame = new Server();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public Server() {
        setTitle("Server");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 550, 400);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        JLabel lblPort = new JLabel("Port:");
        lblPort.setBounds(10, 11, 24, 14);
        contentPane.add(lblPort);

        textFieldPort = new JTextField();
        textFieldPort.setBounds(44, 8, 114, 20);
        contentPane.add(textFieldPort);
        textFieldPort.setColumns(10);

        JButton buttonStart = new JButton("start");
        buttonStart.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                startServer();
            }
        });
        buttonStart.setBounds(168, 7, 89, 23);
        contentPane.add(buttonStart);

        listProtocoll = new List();
        listProtocoll.setBounds(10, 44, 368, 250);
        contentPane.add(listProtocoll);

        textFieldMessage = new JTextField();
        textFieldMessage.setBounds(10, 300, 267, 20);
        contentPane.add(textFieldMessage);
        textFieldMessage.setColumns(10);

        JButton btnSend = new JButton("send");
        btnSend.setBounds(289, 300, 89, 23);
        contentPane.add(btnSend);

        listUsers = new List();
        listUsers.setBounds(404, 44, 120, 214);
        contentPane.add(listUsers);

        JButton btnKick = new JButton("kick");
        btnKick.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                try {
                    kickUser();
                } catch (IOException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            }
        });
        btnKick.setBounds(414, 264, 89, 23);
        contentPane.add(btnKick);
    }

    /**
     * Methods
     * 
     * @throws IOException
     */
    private void startServer() {
        if (!textFieldPort.getText().toString().trim().equals("")) {
            try {
                listen = new ServerSocket(Integer.valueOf(
                        textFieldPort.getText()).intValue());

                connect = new Thread(this);
                connect.start();

                listProtocoll.add("Server started.");
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    private void listen() {
        while (true) {
            try {
                Socket socket = listen.accept();

                Thread t = new Thread(new Handler(this, socket));
                t.start();
            } catch (Exception e) {
                System.err.print("Fehler.");
            }
        }
    }

    protected void broadcast(String message) throws IOException {
        // TODO: broadcast-method
        for (Handler handler : activeUsers) {
            handler.sendMessageToClient(message);
        }
    }

    protected boolean checkName(String name) {
        for (Handler handler : activeUsers) {
            if (handler.getClientname() == name) {
                return false;
            }
        }
        return true;
    }

    protected void addUser(Handler newClient) throws IOException {
        // TODO: add new user to activeUsers
        activeUsers.add(newClient);
        refreshList();
        sendUserList();
        broadcast("MSG¿" + newClient.getClientname() + " joined the chat.");
    }

    protected void removeUser(Handler removingClient) {
        // TODO: remove
        int index = 0;
        for (Handler handler : activeUsers) {
            if (handler == removingClient) {
                activeUsers.remove(index);
            }
            index++;
        }
        try {
            refreshList();
            sendUserList();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    private void kickUser() throws IOException {
        // TODO: kick selected user from chat and broadcast kick-message
        activeUsers.remove(listUsers.getSelectedIndex());
        refreshList();
        sendUserList();
        broadcast("user " + activeUsers.get(listUsers.getSelectedIndex())
                + " has been kicked.");
    }

    private void refreshList() {
        for(Handler handler: activeUsers) {
            listUsers.add(handler.getClientname());
        }
    }

    private void sendUserList() throws IOException {
        // TODO: get the names from all active clients and build a String("USR"
        // + "¿" + name1 + "¿" + name2...)
        // TODO: broadcast built String
        String listString = "USR¿";

        for (Handler handler : activeUsers) {
            listString = listString + handler.getClientname() + "¿";
        }

        broadcast(listString);
    }

    @Override
    public void run() {
        // TODO Auto-generated method stub
        listen();
    }
}

处理程序

public class Handler implements Runnable {
    private DataInputStream in;
    private DataOutputStream out;
    private Socket socket;
    private Server server;
    private Date time;
    private String[] split;
    private String clientname;

    public Handler(Server server, Socket socket) throws IOException {
        this.socket = socket;
        if (in == null) {
            in = new DataInputStream(socket.getInputStream());
        }
        if (out == null) {
            out = new DataOutputStream(socket.getOutputStream());
        }
    }

    @Override
    public void run() {
        // TODO Auto-generated method stub
        try {
            receiveMessage();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    private void receiveMessage() throws IOException {
        // TODO Auto-generated method stub
        String inMessage = in.readUTF();
        while (in.readUTF() != null) {
            inMessage = in.readUTF();
            split = inMessage.split("¿");

            if(split[0].equals("NIC")) {
                if(server.checkName(split[2])) {
                    this.clientname = split[2];
                    server.addUser(this);
                }
            }
            if(split[0].equals("MSG")) {server.broadcast(buildMessage(inMessage));}
            if(split[0].equals("BYE")) {disconnect();}
            if(split[0].equals("help")){sendCommands();}
        }

    }
    private void sendCommands() throws IOException {
        sendMessageToClient("MSG" + "¿" + "help = show all available commands.");
        sendMessageToClient("MSG" + "¿" + "bye = disconnect from server.");
    }
    private void disconnect() throws IOException {
        server.removeUser(this);
        socket.close();
        socket.shutdownInput();
        socket.shutdownOutput();
        socket = null;
    }
    private String buildMessage(String message) {
        // TODO: build message with time and parameter-message
        SimpleDateFormat formatter = new SimpleDateFormat("HH:mm");
        time = new Date();

        String newMessage = "" + formatter.format(time) + " " + message;

        return newMessage;
    }
    public String getClientname() {
        return this.clientname;
    }
    protected void sendMessageToClient(String message) throws IOException {
        // TODO Auto-generated method stub
        out.writeUTF(message);
    }
}

客户端

public class Client extends JFrame implements Runnable {

    private JPanel contentPane;
    private JTextField textFieldIp;
    private JTextField textFieldPort;
    private JTextField textFieldMessage;

    private String message;
    private DataInputStream in;
    private DataOutputStream out;
    private Socket socket;
    private List listProtocoll;
    private JLabel lblName;
    private JTextField textFieldName;
    private String name;
    private String ip;
    private int port;
    private List listUsers;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Client frame = new Client();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     * 
     * @throws IOException
     */
    public Client() throws IOException {
        setTitle("Chat");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 549, 350);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        JLabel lblIp = new JLabel("IP:");
        lblIp.setBounds(10, 11, 14, 14);
        contentPane.add(lblIp);

        textFieldIp = new JTextField();
        textFieldIp.setBounds(34, 8, 86, 20);
        contentPane.add(textFieldIp);
        textFieldIp.setColumns(10);

        JLabel lblPort = new JLabel("Port:");
        lblPort.setBounds(130, 11, 29, 14);
        contentPane.add(lblPort);

        textFieldPort = new JTextField();
        textFieldPort.setBounds(169, 8, 106, 20);
        contentPane.add(textFieldPort);
        textFieldPort.setColumns(10);

        JButton btnConnect = new JButton("connect");
        btnConnect.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                try {
                    connect();
                } catch (IOException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            }
        });
        btnConnect.setBounds(434, 7, 89, 23);
        contentPane.add(btnConnect);

        listProtocoll = new List();
        listProtocoll.setBounds(10, 54, 391, 204);
        contentPane.add(listProtocoll);

        listUsers = new List();
        listUsers.setBounds(413, 55, 110, 203);
        contentPane.add(listUsers);

        textFieldMessage = new JTextField();
        textFieldMessage.setBounds(10, 281, 384, 20);
        contentPane.add(textFieldMessage);
        textFieldMessage.setColumns(10);

        Button button = new Button("send");
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                sendMessage(buildMessage("MSG"));
            }
        });
        button.setBounds(413, 281, 70, 22);
        contentPane.add(button);

        lblName = new JLabel("Name:");
        lblName.setBounds(285, 11, 46, 14);
        contentPane.add(lblName);

        textFieldName = new JTextField();
        textFieldName.setBounds(325, 8, 99, 20);
        contentPane.add(textFieldName);
        textFieldName.setColumns(10);

    }

    /***
     * Methods
     * 
     * @throws IOException
     * @throws UnknownHostException
     */
    private void connect() throws UnknownHostException, IOException {
        // TODO: connect body
        this.name = textFieldName.getText().toString().trim();
        this.ip = textFieldIp.getText().toString().trim();
        this.port = Integer.valueOf(textFieldPort.getText().trim()).intValue();

        System.out.println("trying to connect to Server " + ip + " / " + port);

        socket = new Socket(ip, port);

        if (in == null) {
            in = new DataInputStream(socket.getInputStream());
        }
        if (out == null) {
            out = new DataOutputStream(socket.getOutputStream());
        }

        out.writeUTF("NIC" + "¿" + textFieldName.getText().toString().trim());

        System.out.println("Successfully connected!" + "\n");
    }

    protected void disconnect() throws IOException {
        // TODO: disconnect body
        socket.close();
        socket.shutdownInput();
        socket.shutdownOutput();
    }

    protected void showMessage(String message) {
        // TODO: add message to protocol-list
        listProtocoll.add(message);
        listProtocoll.makeVisible(listProtocoll.getItemCount() - 1);
    }

    private void sendMessage(String capital) {
        // TODO: send message to server which broadcasts the message
        try {
            out.writeUTF(buildMessage(capital));
        } catch (Exception e) {
            System.err.print(e);
        }
    }

    private String buildMessage(String capital) {
        // TODO: build message with nickname and text
        // the following code should be in the Server-class
        // if (textFieldName.getText().toString().trim() == "help") {
        // showCommands();
        // }
        // if (textFieldName.getText().toString().trim() == "exit") {
        // disconnect();
        // }
        message = capital + "¿" + textFieldName.getText().toString() + ": "
                + textFieldMessage.getText().toString();

        return message;
    }

    protected void receiveMessage() throws Exception {
        // TODO: wait for incoming message then call showMessage()
        message = in.readUTF();
        while (in.readUTF() != null) {
            message = in.readUTF();
            checkMessage(message);
        }
    }

    private void checkMessage(String message) {
        String[] split = message.split("¿");
        if (split[0].equals("USR")) {
            refreshUserlist(split);
        }
        if (split[0].equals("MSG")) {
            showMessage(split[1]);
        }
    }

    public String getName() {
        return this.name;
    }

    private void refreshUserlist(String[] newList) {
        listUsers.removeAll();
        for (int i = 1; i < newList.length; i++) {
            listUsers.add(newList[i]);
        }
    }

    @Override
    public void run() {
        // TODO Auto-generated method stub
        try {
            receiveMessage();
        } catch (Exception e) {
            System.err.print(e);
        }
    }

}

Answer 1

附加到 0.0.0.0(所有网络接口(interface))而不是特定的主机名或 IP 号码。