java聊天服务器查看在线帐户

Question

我正在用 Java 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”时它发送消息但文本光标转到下一行。我使用 setCaretPosition(0); 但它没有用。

您可以看到下图并理解问题。

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，但问题是我如何传递列表并在 client.java 中使用它。这是我的客户端代码:

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，我将不胜感激。还是谢谢你。

Answer 1

这是因为您清除了监听器 keyPressed 方法中的文本字段。因此，键事件仍然存在，然后添加文本(在本例中为换行符)。快速而肮脏的解决方法是在调用 write() 之前添加一个 evt.consume();。