java - 无法将多个客户端添加到此 Java 聊天中

Question

我正在尝试使用 java 构建一个具有多个客户端和单个服务器的简单聊天应用程序，但我似乎一次不能拥有多个客户端类型。

当只有客户端和服务器时一切正常。

但是，当我尝试添加第二个客户端时，事情就出了问题。

第二个客户端能够建立连接，但随后代码的流部分中的某些内容似乎被阻塞，因为代码无法继续通过第二个客户端中的 setupStreams 点。

这是客户端:

package instantMessanger;

import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import java.util.Random;
import javax.swing.text.AttributeSet;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyleContext;



 public class ClientRunner {
    public static void main(String[] args){
        Client client = new Client("127.0.0.1"); //using local host
        client.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        client.startRunning();
    }
}

public class Client extends JFrame{

    /**
     * An Instant Messaging Client
     */
    private static final long serialVersionUID = 1L;
    private JTextField userText;
    private JTextPane chatWindow;
    private JScrollPane sPane;
    private ObjectOutputStream output;
    private ObjectInputStream input;
    private String message = "";
    private String serverIP; 
    private Socket connection;
    private String ClientUserName; 

    //constructor
    public Client(String host){
        super("Client Instant Messanger");
        serverIP = host;
        userText = new JTextField();
        userText.setEditable(false);
        userText.addActionListener(
                new ActionListener(){
                    public void actionPerformed(ActionEvent event){
                        sendMessage(event.getActionCommand()); //takes text from text area and sends it
                        userText.setText("");
                    }
                }
        );
        add(userText, BorderLayout.NORTH);
        //chatWindow = new JTextArea();
        chatWindow = new JTextPane();
        sPane = new JScrollPane(chatWindow);
        add(sPane, BorderLayout.CENTER);
        setSize(600, 300);
        setVisible(true); 
    }

    //start
    public void startRunning(){
        try{
            connectToServer();
            setupStreams();
            whileChatting();
        }catch(EOFException e){
            showMessage("\n Client terminated the connection ");
        }catch(IOException i){
            i.printStackTrace();
        }finally{
            cleanUp();
        }
    }

    //connect to server
    private void connectToServer() throws IOException{
        showMessage("Attempting connection... \n");
        connection = new Socket(InetAddress.getByName(serverIP), 6879);
        showMessage("Connected to: " + connection.getInetAddress().getHostName());
    }

    //generate username with random (unique) number
    private void generateUserName(){
        ClientUserName = "CLIENT"+ (int)Math.floor(Math.random() * ( 10 ));
    }

    //set up streams to send and receive messages
    private void setupStreams() throws IOException{
        output = new ObjectOutputStream(connection.getOutputStream());
        output.flush();
        input = new ObjectInputStream(connection.getInputStream());
    }

    //while chatting with server
    private void whileChatting() throws IOException{
        generateUserName();
        ableToType(true);
        do{
            try{
                message = (String) input.readObject();
                showMessage("\n" + message);
            }catch(ClassNotFoundException c){
                showMessage("\n user input not accepted");
            }
        }while(!message.equals("SERVER - END"));
    }

    //clean up
    private void cleanUp(){
        showMessage("\n Closing the chat!");
        ableToType(false);
        try{
            output.close();
            input.close();
            connection.close();
        }catch(IOException i){
            i.printStackTrace();
        }   
    }

    //send message to server
    private void sendMessage(String message){
        try{
            output.writeObject(ClientUserName + " — " + message);
            output.flush();
            showMessage("\n" + ClientUserName + " — " + message);
        }catch(IOException ioE){
            appendToPane(chatWindow, "\n Error sending message", Color.RED);
        }
    }

    //change + update chatWindow
    private void showMessage(final String message){
        System.out.println("the message is: " + message + " ends here");
        SwingUtilities.invokeLater(
                //create the thread
                new Runnable(){
                    public void run(){
                        if(message.contains("CLIENT")){
                            appendToPane(chatWindow, message, Color.blue); //append the message to the history
                        }else if(message.contains("SERVER")){
                            appendToPane(chatWindow, message, Color.MAGENTA); 
                        }else{
                            appendToPane(chatWindow, message, Color.green); 
                        }
                    }
                }
        );
    }

    //allow user to type into text box
    private void ableToType(final boolean tof){
        SwingUtilities.invokeLater(
                new Runnable(){
                    public void run(){
                        userText.setEditable(tof);
                    }
                }
        );
    }

    //append to pane
    private void appendToPane(JTextPane tp, String msg, Color c)
    {
        StyleContext sc = StyleContext.getDefaultStyleContext();
        AttributeSet aset = sc.addAttribute(SimpleAttributeSet.EMPTY, StyleConstants.Foreground, c);

        aset = sc.addAttribute(aset, StyleConstants.FontFamily, "Lucida Console");
        aset = sc.addAttribute(aset, StyleConstants.Alignment, StyleConstants.ALIGN_JUSTIFIED);

        int len = tp.getDocument().getLength();
        tp.setCaretPosition(len);
        tp.setCharacterAttributes(aset, false);
        tp.replaceSelection(msg);
    }



}

这是服务器:

package instantMessanger;

import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.AttributeSet;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyleContext;

public class ServerRunner {
    public static void main(String[] args){
        Server server = new Server();
        server.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //close when hit x
        server.startRunning(); //run the server class
      }
   }

public class Server extends JFrame{

    /**
     * An Instant Messaging Server
     */
    private static final long serialVersionUID = 3671904040330502199L;
    private JTextField userText;
    private JTextPane chatWindow;
    private ObjectOutputStream output;
    private ObjectInputStream input;
    private ServerSocket server;
    private Socket connection;
    private String text = "";

    //constructor
    public Server(){
        super("Server Instant Messanger");
        userText = new JTextField();
        userText.setEditable(false); //before connected to anyone else, can't type
        userText.addActionListener(
                new ActionListener(){
                    public void actionPerformed(ActionEvent event){
                        sendMessage(event.getActionCommand()); //send the text when enter is hit
                        userText.setText(""); //after the text is sent, message field goes back to blank
                    }
                }
        );
        add(userText, BorderLayout.NORTH);
        chatWindow = new JTextPane();
        add(new JScrollPane(chatWindow));
        setSize(600, 300);
        setVisible(true); 
    }

    //set up and run the server
    public void startRunning(){
        try{
            server = new ServerSocket(6879, 100); //port num is first arg
            while (true){
                try{
                    //connect and have conversation
                    waitForConnection();
                    setupStreams();
                    whileChatting();
                }catch(EOFException eofException){
                    //when host ends the connection, throw and catch exception
                    showMessage("\n Server ended the connection");
                }finally{
                    cleanUp();
                }
            }
        }catch(IOException ioException){
            ioException.printStackTrace();
        }
    }

    //wait for connection, then display connection info
    private void waitForConnection() throws IOException{
        showMessage("Waiting for someone to connect ... \n");
        connection = server.accept(); //accept a connection and create socket 
        new ThreadedSocket(connection).start();
        showMessage("Connected to: "+ connection.getInetAddress().getHostName() );
    }

    public class ThreadedSocket extends Thread {
        Socket socket;
              ThreadedSocket( Socket socket ) {
                this.socket = socket;
              }
    }

    //get stream to send and receive data
    private void setupStreams() throws IOException {
        output = new ObjectOutputStream(connection.getOutputStream()); // stream for send message 
        output.flush();
        input = new ObjectInputStream(connection.getInputStream()); //stream for receive message
    }

    //during the chat conversation
    private void whileChatting() throws IOException{
        ableToType(true); //allow the user to type
        do{
            try{
                text = (String) input.readObject();
                showMessage('\n' + text);
            }catch(ClassNotFoundException classNotFoundException){
                showMessage("\n user input not accepted");
            }       
        }while(!text.contains("END")); //if user types END, end convo
    }

    //close streams and sockets after done to cleanup
    private void cleanUp() {
        showMessage("\n Closing connections..... \n");
        ableToType(false);
        try{
            output.close(); //close input
            input.close();  //close output
            connection.close();  //close the connection     
        }catch(IOException ioException){
            ioException.printStackTrace();
        }
    }

    //send a message to the client
    private void sendMessage(String message){
        try{
            output.writeObject("SERVER - " + message); //replace server with username?
            output.flush(); //flush the buffer
            showMessage("\nSERVER - " + message);
        }catch(IOException ioException){
            appendToPane(chatWindow,"\n Error: Message not sent", Color.red);
        }
    }

    //update the chatWindow
    private void showMessage(final String text){
        SwingUtilities.invokeLater( //create a thread that updates the GUI
                new Runnable(){
                    public void run(){
                        if(text.contains("CLIENT")){
                            appendToPane(chatWindow, text, Color.blue); //append the message to the history
                        }else if(text.contains("SERVER")){
                            appendToPane(chatWindow, text, Color.MAGENTA); 
                        }else{
                            appendToPane(chatWindow, text, Color.green); 
                        }
                    }
                }
        );
    }

    //let the user type when connected
    private void ableToType(final boolean tof){
        SwingUtilities.invokeLater( //create a thread that updates the GUI
                new Runnable(){
                    public void run(){
                        userText.setEditable(tof); //set to passed in true or false
                    }
                }
        );
    }

    //append to pane
    private void appendToPane(JTextPane tp, String msg, Color c)
    {
         StyleContext sc = StyleContext.getDefaultStyleContext();
         AttributeSet aset = sc.addAttribute(SimpleAttributeSet.EMPTY, StyleConstants.Foreground, c);

         aset = sc.addAttribute(aset, StyleConstants.FontFamily, "Lucida Console");
         aset = sc.addAttribute(aset, StyleConstants.Alignment, StyleConstants.ALIGN_JUSTIFIED);

         int len = tp.getDocument().getLength();
         tp.setCaretPosition(len);
         tp.setCharacterAttributes(aset, false);
         tp.replaceSelection(msg);
     }


}

任何和所有的帮助将不胜感激!

Answer 1

您正尝试对服务器的所有连接使用一个变量。这不起作用，因为一旦创建新的套接字连接，以前的连接将被垃圾收集。当接受新连接时，请将其添加到列表中。我不会提供代码示例，因为这需要更改代码的大部分部分并且会使答案变得臃肿。

请注意，它还要求您为每个连接创建单独的输入/输出流，而现在一旦建立新连接，您就会覆盖先前连接的流。