Question

我正在Java上实现一个基本的聊天服务器。实际上我完成了基本的事情，并试图改进它。

现在我想尝试制作一个显示谁在线的列表。我有个问题。我在JTextPane组件上获取字符串，当我按“ENTER”时它会发送消息，但文本光标会转到下一行。我使用setCaretPosition(0);但它没有用。

您可以看到下面的图片并了解问题。

enter image description here

这是我的服务器和服务器线程代码;

import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;


public class Server {

    private ServerSocket ss;
    private Socket s;
    Map<Socket,DataOutputStream> list = new HashMap<Socket,DataOutputStream>();

    public Server(int port_number) throws IOException{

        create_Server(port_number);
    }

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

        int port_number=23;

        new Server(port_number);
    }

    private void create_Server(int port_number) throws IOException{

        ss = new ServerSocket(port_number);

        System.out.println("Server is ready!");

        while(true){

            s=ss.accept();

            System.out.println(s.getLocalAddress().getHostName() + " was connected!");

                        send_con_mes();

            list.put(s,new DataOutputStream(s.getOutputStream()) );

            new ServerThread(s,this).start();
        }

    }

        private void send_con_mes() throws IOException{

                Set<Socket> sckt_list = list.keySet();
        Iterator<Socket> itr = sckt_list.iterator();
                DataOutputStream daos;

                String str;
                Socket sckt;

                while(itr.hasNext()){

                    sckt=itr.next();
                    str = sckt.getLocalAddress().getHostName() + " was connected..." ;

                    daos = list.get(sckt);
                    daos.writeUTF(str);

                }

        }

    public void send_to_All(String msg, Socket socket) throws IOException{

        synchronized(list){

            Set<Socket> sckt_list = list.keySet();
            Iterator<Socket> itr = sckt_list.iterator();
            DataOutputStream daos;

            while(itr.hasNext()){

                Socket sck = itr.next();

                if(sck!=socket){

                    daos = list.get(sck);
                    daos.writeUTF(msg);

                }
            }
        }
    }

    public void remove_Connection(Socket s) throws IOException{

        synchronized(list){

            list.remove(s);
            System.out.println(s.getLocalAddress().getHostName() + " was disconnected!");
            s.close();
        }
    }

}

import java.io.DataInputStream;
import java.io.IOException;
import java.net.Socket;


public class ServerThread extends Thread {

    private Socket s;
    private Server srv;

    public ServerThread(Socket s,Server srv){
        this.s = s;
        this.srv = srv;
    }

    @Override
    public void run() {

        String msg;
                DataInputStream dis;

        try {
            dis = new DataInputStream(s.getInputStream());

            while(true){

                msg = dis.readUTF();
                srv.send_to_All(msg, s);

            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        finally{
            try {
                srv.remove_Connection(s);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

}

所以我想我必须在server.java中实现列表，但问题是如何传递列表并在client.java中使用它。这是我的客户代码：

import java.awt.Frame;
import java.awt.event.KeyEvent;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.DefaultListModel;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/*
 * Client.java
 *
 * Created on 02.Eyl.2011, 16:46:44
 */
/**
 *
 * @author BURAKTAS
 */
public class Client extends javax.swing.JFrame implements Runnable {

    private DataOutputStream dos;
    private DataInputStream dis;
    private Socket s;
    private String Client_name;
    private String Ip_addr;
    private DefaultListModel listModel=new DefaultListModel();


    /** Creates new form Client */
    public Client() {
        initComponents();
        Screen.setEditable(false);

        acc_list.setVisibleRowCount(6);
        listModel.addElement(Client_name);



        start_Chat();

    }

    @Override
    public void run() {

        try {

            while(true){

            String message = dis.readUTF();
            Screen.append(message + "\n");
            }

        } catch (IOException ex) {
            Logger.getLogger(Client.class.getName()).log(Level.SEVERE, null, ex);
        }

    }



    public void start_Chat() {
        try {

            Ip_addr = JOptionPane.showInputDialog("Enter the IP number of the server to connect : ");
            s = new Socket(Ip_addr, 23);

            Client_name = JOptionPane.showInputDialog("Enter your Nickname : ");

            dis = new DataInputStream(s.getInputStream());
            dos = new DataOutputStream(s.getOutputStream());

            new Thread(Client.this).start();

        } catch (UnknownHostException ex) {
            JOptionPane.showMessageDialog(rootPane, "Socket can not connected", "ERROR", JOptionPane.ERROR_MESSAGE);
        } catch (IOException ex) {
            JOptionPane.showMessageDialog(rootPane, "Socket can not connected", "ERROR", JOptionPane.ERROR_MESSAGE);
            start_Chat();
        }

    }

    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        font_chooser = new javax.swing.JColorChooser();
        jScrollPane1 = new javax.swing.JScrollPane();
        Screen = new javax.swing.JTextArea();
        Send_Button = new javax.swing.JButton();
        jScrollPane2 = new javax.swing.JScrollPane();
        acc_list = new javax.swing.JList();
        disco_button = new javax.swing.JButton();
        jScrollPane3 = new javax.swing.JScrollPane();
        Text_Field = new javax.swing.JTextPane();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("BrkChat_Server vs 1.0");
        setResizable(false);

        Screen.setColumns(20);
        Screen.setRows(5);
        jScrollPane1.setViewportView(Screen);

        Send_Button.setText("Send");
        Send_Button.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                Send_ButtonActionPerformed(evt);
            }
        });

        acc_list.setModel(new javax.swing.AbstractListModel() {
            String[] strings = { "Item 1", "Item 2", "Item 3", "Item 4", "Item 5" };
            public int getSize() { return strings.length; }
            public Object getElementAt(int i) { return strings[i]; }
        });
        acc_list.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_INTERVAL_SELECTION);
        jScrollPane2.setViewportView(acc_list);

        disco_button.setText("Disconnect");
        disco_button.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                disco_buttonActionPerformed(evt);
            }
        });

        Text_Field.setCursor(new java.awt.Cursor(java.awt.Cursor.TEXT_CURSOR));
        Text_Field.addKeyListener(new java.awt.event.KeyAdapter() {
            public void keyPressed(java.awt.event.KeyEvent evt) {
                Text_FieldKeyPressed(evt);
            }
        });
        jScrollPane3.setViewportView(Text_Field);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jScrollPane3, javax.swing.GroupLayout.DEFAULT_SIZE, 383, Short.MAX_VALUE)
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 383, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(disco_button, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 108, Short.MAX_VALUE)
                    .addComponent(Send_Button, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 108, Short.MAX_VALUE)
                    .addComponent(jScrollPane2, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 108, Short.MAX_VALUE))
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 286, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jScrollPane2, javax.swing.GroupLayout.DEFAULT_SIZE, 288, Short.MAX_VALUE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(Send_Button, javax.swing.GroupLayout.DEFAULT_SIZE, 79, Short.MAX_VALUE)
                    .addComponent(jScrollPane3, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.PREFERRED_SIZE, 76, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(disco_button, javax.swing.GroupLayout.PREFERRED_SIZE, 31, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(11, 11, 11))
        );

        pack();
    }// </editor-fold>

private void write(){

            try {

            Text_Field.setCaretPosition(0);
            String str = Text_Field.getText();

            dos.writeUTF(Client_name + " : " + str);
            Screen.append(Client_name + " : " + str + "\n");
            Text_Field.setText("");
        } catch (IOException ex) {
            Logger.getLogger(Client.class.getName()).log(Level.SEVERE, null, ex);
        }
}

private void Send_ButtonActionPerformed(java.awt.event.ActionEvent evt) {                                            

    write();

}                                           

private void disco_buttonActionPerformed(java.awt.event.ActionEvent evt) {
        try {
            s.close();
            this.setVisible(false);
            System.exit(0);
        } catch (IOException ex) {
            Logger.getLogger(Client.class.getName()).log(Level.SEVERE, null, ex);
        }
}

private void Text_FieldKeyPressed(java.awt.event.KeyEvent evt) {

        if(evt.getKeyCode()==KeyEvent.VK_ENTER){
            write();

        }
}

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Windows".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(Client.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Client.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Client.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Client.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {

                new Client().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JTextArea Screen;
    private javax.swing.JButton Send_Button;
    private javax.swing.JTextPane Text_Field;
    private javax.swing.JList acc_list;
    private javax.swing.JButton disco_button;
    private javax.swing.JColorChooser font_chooser;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JScrollPane jScrollPane2;
    private javax.swing.JScrollPane jScrollPane3;
    // End of variables declaration

}

如果你能帮助我，我感激不尽。无论如何，谢谢。

Answer 1

这是因为您清除了侦听器keyPressed方法中的文本字段。因此，关键事件仍然存在，并且之后添加文本（在这种情况下为换行符）。快速而肮脏的解决方法是在致电evt.consume();之前添加write()。

Answer 2

实现此目的的一种方法是实现一些事件，该事件包含每次用户连接/断开连接时发送给所有用户的用户名列表。为了简单起见，您还可以从FTP实现中获取一个页面，并为每个用户使用两个通道 - 一个用于文本，另一个用于系统命令。

无论哪种方式，您基本上只需序列化包含所有必要信息的事件并将其发送给所有客户端。那些基本上只需要反序列化它，检查它们有什么样的事件并相应地处理它。这样您就可以让Java Serialization API处理所有复杂的工作 - 尽管您也可以定义自己的协议并使用protobuf或其他东西（更高效;更多工作）。

java聊天服务器查看在线帐户

2 个答案: