Java学习笔记_网络+多线程

支持同时收发的客户端和服务器端

客户端

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

public class ChatClient {
    private JTextArea incoming;
    private JTextField outgoing;
    private PrintWriter writer;
    private BufferedReader reader;
        
    public static void main(String[] args) {
        ChatClient client = new ChatClient();
        client.go();
    }
    
    private void go() {
        build_gui();
        setup_net();
    }
    
    private void build_gui() {
        JFrame frame = new JFrame("Chat Client");
        JPanel panel = new JPanel();
        
        incoming = new JTextArea(15, 50);
        incoming.setLineWrap(true);
        incoming.setWrapStyleWord(true);
        incoming.setEditable(false);
        JScrollPane qScroller = new JScrollPane(incoming);
        qScroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
        qScroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
        panel.add(incoming);
        
        outgoing = new JTextField(20);
        panel.add(outgoing);
        
        JButton button = new JButton("Send");
        button.addActionListener(new SendButtonListener());
        panel.add(button);
        
        frame.add(BorderLayout.CENTER, panel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(600, 400);        
        frame.setVisible(true);
    }
    
    public class SendButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent a) {
            String msg = outgoing.getText();
            try {
                writer.println(msg);
                writer.flush();
            } catch (Exception ex) { ex.printStackTrace(); }
            outgoing.setText("");
            outgoing.requestFocus();
        }
    }
    
    class ReceiveThreadJob implements Runnable {
        public void run() {
            String msg;
            try {
                while ( (msg = reader.readLine()) != null ) {
                    incoming.append(msg + "\n");
                }
            } catch (IOException ex) { System.out.println("server disconnected"); }        
        }
    }
    
    private void setup_net() {
        try {
            Socket s = new Socket("127.0.0.1", 4242);
            writer = new PrintWriter(s.getOutputStream());
            InputStreamReader streamReader = new InputStreamReader( s.getInputStream() );
            reader = new BufferedReader( streamReader );    

            Runnable receive_thread_job = new ReceiveThreadJob();
            Thread receive_thread = new Thread( receive_thread_job );
            receive_thread.start();
            
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}

服务器端

import java.io.*;
import java.net.*;
import java.util.ArrayList;

public class ChatServer {
    BufferedReader reader;
    ArrayList<PrintWriter> writer_array = new ArrayList<PrintWriter>();

    public static void main(String[] args) {
        ChatServer server = new ChatServer();
        server.go();
    }
    
    private void go() {
        setup_net();
    }
    
    private void setup_net() {
        try {
            ServerSocket serverSock = new ServerSocket(4242);
            while (true) {
                Socket s = serverSock.accept();
                System.out.println("client connected");
                InputStreamReader streamReader = new InputStreamReader( s.getInputStream() );
                reader = new BufferedReader( streamReader );                            
                PrintWriter writer = new PrintWriter(s.getOutputStream());
                writer_array.add(writer);                
                Runnable server_proc_thread_job = new ServerProcThreadJob();
                Thread server_proc = new Thread( server_proc_thread_job );
                server_proc.start();
            }
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
    
    class ServerProcThreadJob implements Runnable {
        public void run() {
            String msg;
            try {
                while ( (msg = reader.readLine()) != null ) {
                    System.out.println(msg);
                    for ( PrintWriter writer: writer_array ) {
                        writer.println(msg);
                        writer.flush();
                    }
                }
            } catch (IOException ex) { System.out.println("client disconnected"); }
        }
    }
}