A simple socket chat demo

ChatClient.java

package socket;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Iterator;

/**
 * 实现一个多人聊天Demo
 * ChatClient：客户端，可以发送消息
 * ChatServer：服务端，接收消息并发送给所有用户
 * Created by tikitoo on 2/6/15.
 */
public class ChatClient {
    JTextArea inComing;
    JTextField outGoing;
    BufferedReader reader;
    PrintWriter writer;
    Socket socket;

    public static void main(String[] args) {
        new ChatClient().go();
    }

    /**
     * 设置界面
     */
    public void go() {
        JFrame frame = new JFrame("Simple Chat Client");
        JPanel mainPanel = new JPanel();

        inComing = new JTextArea(15, 50);
        inComing.setLineWrap(true);
        inComing.setWrapStyleWord(true);
        inComing.setEditable(false);
        inComing.setBackground(Color.DARK_GRAY);

        // 添加滚动
        JScrollPane scrollPane = new JScrollPane(inComing);
        scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
        scrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);

        outGoing = new JTextField(20);
        JButton sendBtn = new JButton("Send");
        sendBtn.addActionListener(new SendButtonListener());

        mainPanel.add(scrollPane);
        mainPanel.add(outGoing);
        mainPanel.add(sendBtn);

        setUpNetworking();

        // 多线程读取消息
        Thread readerThread = new Thread(new InComingReader());
        readerThread.start();

        frame.getContentPane().add(BorderLayout.CENTER, mainPanel);
        frame.setSize(400, 500);
        frame.setVisible(true);
    }

    /**
     * Socket 连接
     */
    private void setUpNetworking() {
        try {
            socket = new Socket("127.0.0.1", 8902);
            InputStreamReader streamReader = new InputStreamReader(socket.getInputStream());
            reader = new BufferedReader(streamReader);

            writer = new PrintWriter(socket.getOutputStream());
            System.out.println("network connecting");
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    /**
     * 发送按钮监听
     *   使用输出流发送数据给服务器
     */
    public class SendButtonListener implements ActionListener {
        @Override
        public void actionPerformed(ActionEvent e) {
            writer.println(outGoing.getText());
            writer.flush();

            outGoing.setText("");
            outGoing.requestFocus();
        }
    }

    /**
     * 读取服务器发送过来的数据
     */
    public class InComingReader implements Runnable {
        @Override
        public void run() {
            String message;
            try {
                while ((message = reader.readLine()) != null) {

                    System.out.println("read: " + message);
                    // inComing.append(message + "\n");
                    inComing.setText(message);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

ChatServer.java

package socket;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Iterator;

/**
 * 服务器端
 *   接受数据，并将接收的数据转发给所有用户
 * Created by tikitoo on 2/6/15.
 */
public class ChatServer {

    /** 将读取的PrintWriter（不同客户端） 对象 */
    ArrayList clientOutputStream;
    public static void main(String[] args) {
        new ChatServer().go();
    }

    class ClientHandler implements Runnable {
        BufferedReader reader;
        Socket socket;

        public ClientHandler(Socket clientSocket) {
            try {
                socket = clientSocket;
                InputStreamReader isReader = new InputStreamReader(socket.getInputStream());
                reader = new BufferedReader(isReader);

            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        @Override
        public void run() {
            String message;
            try {
                while ((message = reader.readLine()) != null) {
                    System.out.println("read: " + message);
                    tellEveryOne(message);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    void go() {
        clientOutputStream = new ArrayList();
        try {
            ServerSocket ss = new ServerSocket(8902);

            while (true) {
                Socket socket = ss.accept();
                PrintWriter writer = new PrintWriter(socket.getOutputStream());
                clientOutputStream.add(writer);

                Thread t = new Thread(new ClientHandler(socket));
                t.start();
                System.out.println("go a connection");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    void tellEveryOne(String message) {
        Iterator iter = clientOutputStream.iterator();
        while (iter.hasNext()) {
            PrintWriter writer = (PrintWriter) iter.next();
            writer.println(message);
            writer.flush();
        }
    }
}