如何在java Chat中更新JList

Question

抱歉，我这里遇到了问题，相信我，我已经尽力了。但不幸的是，在考虑发帖寻求帮助之前，我无法收回它。提前感谢您付出的时间和精力。

我正在尝试更新我的客户端 JList（userList），以便当新客户端进入时，初始客户端将被更新。但目前，当有一个客户端时，它可以看到自己，但当另一个客户端进入聊天时，只有该客户端看到两个客户端已连接，初始客户端不会使用 JList 上的名称进行更新。 请帮助简化任何答案，因为我不是 Java 专家。谢谢你！

ClientChat 代码：

 import java.io.*;
 import java.net.*;
 import java.awt.*;
 import java.awt.event.*;
 import javax.swing.*;

  public class  ClientChat extends JFrame {
private Toolkit toolkit; 
private JLabel msgLabel;
private JButton sendBtn;
private JTextArea genMsg;
public static JList userList;
private JTextField msgF;
private ObjectOutputStream output;
private ObjectInputStream input;
private Socket client;
private String chatServer;
private int serverport;
private String Client_name;

public ClientChat( String host, int port,String C_Name){

    // set server to which this client connects
    chatServer = host;
    serverport = port;
    Client_name = C_Name;


    toolkit = Toolkit.getDefaultToolkit();      
    if(toolkit.getScreenSize().getWidth() > 600)
        setSize(600, 605);
    else
        setSize((int)toolkit.getScreenSize().getWidth(),(int)toolkit.getScreenSize().getHeight() - 20);         
        setResizable(false);
        Dimension dimension = getSize();    
        setLayout(new FlowLayout());

        setTitle("FRESHER MARKETING COMPANY");      
        addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent evt) { System.exit(0);}});

        Container container = getContentPane();
        container.setLayout(new FlowLayout());

        // create General Message Screen
        genMsg = new JTextArea(30,43);
        genMsg.setEditable(false);
        genMsg.setFont(new java.awt.Font("Times New Roman", 0, 12)); // NOI18N
        container.add( new JScrollPane( genMsg ));
        JPanel genMsgPanel = new JPanel();
        genMsgPanel.setLayout(new BorderLayout());
        genMsgPanel.add(new JScrollPane(genMsg), BorderLayout.EAST);
        genMsgPanel.setBorder(BorderFactory.createLineBorder(Color.black)); 
        container.add(genMsgPanel);

        // create Friend List View
        userList = new JList();
        userList.setPreferredSize(new Dimension(150,423));
        userList.setFont(new java.awt.Font("Times New Roman", 0, 12)); // NOI18N
        container.add(userList);
        JPanel userListPanel = new JPanel();
        userListPanel.setLayout(new BorderLayout());
        userListPanel.add(userList, BorderLayout.CENTER);
        userListPanel.setBorder(BorderFactory.createLineBorder(Color.black));   
        container.add(userListPanel);

        msgLabel = new JLabel ("Message:");
        container.add(msgLabel);
        JPanel msgFPanel = new JPanel();
        msgFPanel.setLayout(new BorderLayout());
        msgFPanel.add(new JScrollPane(msgLabel), BorderLayout.WEST);
        container.add(msgFPanel);

        // create Message Field
        msgF = new JTextField(37);
        msgF.setEnabled( true );
        msgF.setText("");
        msgF.requestFocus();
        msgF.addActionListener(
            new ActionListener() {

            // send message to server
                public void actionPerformed( ActionEvent event )
                {
                    //sendData( event.getActionCommand() );
                }
            } // end anonymous inner class
            ); // end call to addActionListener
        msgFPanel.add(new JScrollPane(msgF), BorderLayout.CENTER);
            }
public void runClient()
{
    // connect to server, get streams, process connection
    try {
        // Step 1: Create a Socket to make connection
        connectToServer();
        // Step 2: Get the input and output streams
        getStreams();
        handShake();
    }// server closed connection
    catch ( EOFException eofException ) {
        System.out.println( "Server terminated connection" );
    }

    // process problems communicating with server
    catch ( IOException ioException ) {
        ioException.printStackTrace();
    }
}
private void connectToServer() throws IOException
{
    genMsg.setText( "Attempting connection\n" );
    // create Socket to make connection to server
    client = new Socket(InetAddress.getByName( chatServer ), serverport );
    // display connection information
    genMsg.append( "Connected to: " +client.getInetAddress().getHostName() );
}

private void getStreams() throws IOException
{
    // set up output stream for objects
    output = new ObjectOutputStream(client.getOutputStream() );
    // flush output buffer to send header information
    output.flush();
}
private void handShake() throws IOException
{
    String message;
    String value[];
    value = new String [100];
    try {
    output.writeObject(Client_name);
    output.flush();
    input = new ObjectInputStream(client.getInputStream() );
    genMsg.append( "\n Client Name Send"  );
    message = (String) input.readObject();
    int i=0;
     while ( !message.equals( "." ) ){

        //genMsg.append("\n"+message );
        value[i++] =message; 
        message = (String) input.readObject();
    }
    userList.setListData(value);
    message = (String) input.readObject();
    genMsg.append("\n"+message );
    }
    // process problems sending object
    catch ( IOException ioException ) {
        genMsg.append( "\nError writing object" );
    }
     catch ( ClassNotFoundException classNotFoundException ) {
        System.out.println( "\nUnknown object type received" );
        }

}
public static void main( String args[] )    { 

    ClientChat application;
    application = new ClientChat( "127.0.0.1",5130,args[0] );
    application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );
    application.runClient();
  }
 } 

ServerChat 代码：

 import java.io.*;
 import java.net.*;
 import java.util.*;
 import java.awt.*;
 import java.awt.event.*;
 import javax.swing.*;

 public class ServerChat extends JFrame 
 {
private ObjectInputStream input;
private ObjectOutputStream output;
private JTextField enterField;
public static JTextArea displayArea;
private ServerSocket server;
private Socket connection;  
private ServerThread c1[];
//private Client Cname;
private static String clientList[];
private int counter = 0;

public ServerChat()
{
    super( "Server" );
    Container container = getContentPane();
    clientList = new String[100];
    // create enterField and register listener
    enterField = new JTextField();
    enterField.setEnabled( false );
    enterField.addActionListener(

    new ActionListener() {
        // send message to client
        public void actionPerformed( ActionEvent event )
        {
            //sendData( event.getActionCommand() );
        }
    } // end anonymous inner class
    ); // end call to addActionListener

    container.add( enterField, BorderLayout.NORTH );
    // create displayArea
    displayArea = new JTextArea();
    container.add( new JScrollPane( displayArea ), BorderLayout.CENTER );
    setSize( 300, 150 );
    setVisible( true );
}
public void runServer()
{
    // set up server to receive connections;
    // process connections
    try {
    // Step 1: Create a ServerSocket.
    server = new ServerSocket( 5130, 100);
    c1 = new ServerThread[100];
    while ( true ) {
        // Step 2: Wait for a connection.
        waitForConnection();
        handShake();
        displayArea.append("\nHanshake Complete");
        //c1[counter] = new ServerThread(connection,counter);   
        //c1[counter].start();
        ++counter;
        }
    }
    // process EOFException when client closes connection
    catch ( EOFException eofException ) {
    System.out.println( "Client terminated connection" );
    }
    // process problems with I/O
    catch ( IOException ioException ) {
    ioException.printStackTrace();
    }
}
private void waitForConnection() throws IOException
{
    displayArea.append( "\nWaiting for connection " );
    // allow server to accept a connection
    connection = server.accept();
    displayArea.append( "\nClient connected : Client");
}
private void handShake() throws IOException
{
    output = new ObjectOutputStream(connection.getOutputStream() );
    output.flush();
    String message;
    input = new ObjectInputStream(connection.getInputStream() );
    try {
        message = (String) input.readObject();
        clientList[counter]= message;
        displayArea.append( "\nClient connected : "+message);
        for (int i=0; i<=counter;i++ )
        {
            output.writeObject(clientList[i]);
            output.flush();
        }
        output.writeObject(".");
        output.flush();
        }
     // catch problems reading from client
    catch ( ClassNotFoundException classNotFoundException ) {
        System.out.println( "\nUnknown object type received" );
        }
        catch ( IOException ioException ) {
    ioException.printStackTrace();
    }
}
 public static void main( String args[] )
{
    ServerChat application = new ServerChat();
    application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );
    application.runServer();
}
}

ServerThread 代码：

import java.io.*;
 import java.net.*;
 import java.awt.*;
 import java.awt.event.*;
 import javax.swing.*;
 public class ServerThread extends Thread 
 {
private Socket connection;
private ObjectOutputStream output;
private ObjectInputStream input;
private int counter;
public ServerThread(Socket con,int count)
{
    connection = con;
    counter = count;

}
public void run()
{
        try 
        {
            getStreams();
            processConnection();
        }
        // process EOFException when client closes connection
    catch ( EOFException eofException ) {
    System.out.println( "Client terminated connection" );
    }

    // process problems with I/O
    catch ( IOException ioException ) {
    ioException.printStackTrace();
    }
}
    private void getStreams() throws IOException
    {
    // set up output stream for objects
    output = new ObjectOutputStream(connection.getOutputStream() );
    // flush output buffer to send header information
    output.flush(); 
    output.writeObject( "SERVER>>> Connection successful");
    output.flush();
    }
private void processConnection() throws IOException
{
    // send connection successful message to client
    String message = "SERVER>>> Connection successful";

    output.writeObject( message );
    output.flush();
}
private void closeConnection() throws IOException
{
    ServerChat.displayArea.append( "\nUser terminated connection" );

    output.close();
    input.close();
    connection.close();
    }
 }

Answer 1

您对Swing 中的并发有真正的问题，所有输出BackGround Tasks 必须包装到 invokeLater() 中，如果您在这里等待可能且重复的网络故障，那么最好将其包装到 invokeAndWait() 中

1) 仅创建一种方法，用于将字符串添加/附加到 JTextArea

2) 方法将字符串添加/附加到 JTextArea 包装到 invokeLater()

3) 检查这个 线程并通过给定示例修改/更改所有方法