一個簡單的局域網Socket聊天程序

原文地址

這是一個簡單的LAN Socket聊天程序，客戶端是Android程序。

下面是關鍵代碼和運行效果：

服務器端代碼關鍵代碼

class ChatService {

    private static final int PORT = 50000;
    private static HashMap<String, Socket> socketList = new HashMap<>();
    private ExecutorService executorService;
    private ServerSocket serverSocket;

    public ChatService () {}

    public void service () {
        try {
            serverSocket = new ServerSocket(PORT);
            executorService = Executors.newCachedThreadPool();
            System.out.println("server start...");
            while (true) {
                Socket client = serverSocket.accept();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(client.getInputStream()));
                String username = bufferedReader.readLine();
                System.out.println(username + " login");
                socketList.put(username, client);
                executorService.execute(new ServerThread(client , bufferedReader));
            }

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static class ServerThread implements Runnable {

        private Socket socket;
        private BufferedReader bufferedReader;
        private PrintWriter printWriter;
        private String message;

        public ServerThread (Socket socket , BufferedReader bufferedReader) throws IOException {
            this.socket = socket;
            this.bufferedReader = bufferedReader;
        }

        @Override
        public void run() {
            try {
                while ((message = bufferedReader.readLine()) != null) {
                    String[] info = message.split("\\|");
                    if (info[2].equals("exit")) {
                        socketList.remove(socket);
                        bufferedReader.close();
                        if (printWriter != null) {
                            printWriter.close();
                        }
                        socket.close();
                        System.out.println(info[0] + " exit");
                        break;
                    } else {
                        sendMessage(info[1]);
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        private void sendMessage(String to) throws IOException {
            System.out.println(message);
            Socket client = socketList.get(to);
            if (client != null) {
                printWriter = new PrintWriter(
                        new BufferedWriter(new OutputStreamWriter(client.getOutputStream())) , true);
                printWriter.println(message);
            }
        }

    }
}

客戶端代碼關鍵代碼（Android）

public class MainActivity extends Activity implements OnClickListener {

    private void login () {
        if (etUsername.getText().toString().equals("")) {
            Toast.makeText(this, "請輸入用戶名", Toast.LENGTH_LONG).show();
            return; 
        } else {
            new loginTask().execute();
        }
    }

    private class loginTask extends AsyncTask<Void, Object, Boolean> {

        @Override
        protected Boolean doInBackground(Void... params) {
            btLogin.setClickable(false);
            try {
                socket = new Socket(IP, PORT);
                printWriter = new PrintWriter(
                        new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())) , true);
                printWriter.println(etUsername.getText().toString());
                bufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                Log.i(TAG, etUsername.getText().toString());
                return true;
            } catch (Exception e) {
                e.printStackTrace();
            } 
            return false;
        }

        @Override
        protected void onPostExecute(Boolean result) {
            if (result) {
                btSend.setClickable(true);
            } else {
                btLogin.setClickable(true);
            }
        }
    }

    private void send () {
        if (etTo.getText().toString().equals("")
                || etMessage.getText().toString().equals("")) {
            Toast.makeText(this, "請輸入完整信息", Toast.LENGTH_LONG).show();
            return; 
        } else {
            new sendTask().execute();
        }
    }

    private class sendTask extends AsyncTask<Void, Object, Boolean> {

        @Override
        protected Boolean doInBackground(Void... params) {
            try {
                String to = etTo.getText().toString();
                String message = etMessage.getText().toString();
                printWriter.println(etUsername.getText().toString() + "|" + to + "|" + message);
                return true;
            } catch (Exception e) {
                e.printStackTrace();
            }
            return false;
        }

        @Override
        protected void onPostExecute(Boolean result) {
            if (result) {
                tvRecord.post(new Runnable() {
                    @Override
                    public void run() {
                        tvRecord.append("\n" + etUsername.getText().toString() + " : " + etMessage.getText().toString());
                    }
                });
            }
        }

    }

    /**
     * 接收消息
     */
    private Runnable runnable = new Runnable() {
        public void run() {
            while (true) {
                try {
                    if (bufferedReader != null && (strMessage = bufferedReader.readLine()) != null) {
                        String[] info = strMessage.split("\\|");
                        strMessage = info[0] + " : " + info[2];
                        tvRecord.post(new Runnable() {
                            @Override
                            public void run() {
                                tvRecord.append("\n" + strMessage);
                            }
                        });
                    }                    
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    };

}

代碼很簡單，實現的功能也很簡單，就是一個一對一的聊天，兩點比較重要：
1、線程池
2、消息格式爲：from|to|message（發送方|接受方|消息）

運行效果

服務器：

客戶端1：

客戶端2：

源碼下載

IM_LAN