示例：Socket应用之简易聊天室

在实际应用中，Server总是在指定的端口上监听是否有Client请求，一旦监听到Client请求，Server就会启动一个线程来响应该请求，而Server本身在启动完线程之后马上又进入监听状态。

示例：Socket应用之简易聊天室

当一个Client连接Server之后，Server将向所有Client发送一个消息，这就需要Server和Client都一直处于监听状态。

在Server，1. 通过一个List来存储所有连接进来的Socket 2. 为每个client开启了一个线程来响应请求。

服务端程序

public class Server {

  private static final int SERVER_PORT = 54321;

  private static List<Socket> mClientList = new ArrayList<Socket>();

  private ExecutorService mExecutorService;

  private ServerSocket mServerSocket;

  public Server () {

    try {

      mServerSocket = new ServerSocket(SERVER_PORT);

      mExecutorService = Executors.newCachedThreadPool();

      socket client = null;

      while(true) {

        client = mServerSocket.accept();

        mClientList.add(client);

        mExecutorService.execute(new ThreadServer(client));

      }

    } catch (IOException e) { }

  }

  // 为每个client独立开启一个线程。

  static class ThreadServer implements Runnable {

    private Socket mSocket;

    private BufferedReader mBufferedReader;

    private PrintWriter mPrintWriter;

    private String mStrMsg;

    public ThreadServer(Socket socket) throw IOException {

      mSocket = socket;

      mBufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream));

      mStrMsg = “user(”+mSocket.getInetAddress()+”) come, total client count: ” + mClientList.size();

      sendMessage();

    }

    public void run() {

      try {

        while((mStrMsg = mBufferedReader.readLine())!=null){

          if(mStrMsg.trim().equals(“exit”)) {

            // 当一个client退出时

            mClientList.remove(mSocket);

            mBufferedReader.close();

            mPrintWriter.close();

            mStrMsg = “user(”+mSocket.getInetAddress()+”) exit, total client count: ” + mClientList.size();

            mSocket.close();

            sendMessage();

            break;

          } else {

            mStrMsg = mSocket.getInetAddress() + “:”+ mStrMsg;

            sendMessage();

          } // else

        } // while

      }  catch(IOException e) { }

    }

    // 发送信息给所有client

    private void sendMessage() throws IOException {

      for(Socket socket : mClientList) {

        mPrintWriter = new PrintWriter(client.getOutputStream(), true);

        mPrintWriter.println(mStrMsg);

      }

    }

  }

}

 

客户端程序

// android client app

在onCreate方法中

// 点击“登录”连接服务器

mSocket = new Socket(SERVER_IP, SERVER_PORT);

// 取得输入输出流

mBufferedReader = new BufferedReader(new InputStreamReader(mSocket.getInputStream()));

mPrintWriter = new PrintWriter(mSocket.getOutputStream(), true);

// 点击“发送消息”

String msg = mMsgBox.getText().toString();

mPrintWriter.print(msg);

mPrintWriter.flush();

// 开启线程监听服务器发来的消息

new Thread(mRunnable).start();

 

// 监听Server发来消息的线程

private Runnable mRunnable = new Runnable(){

  public void run() {

    while(true) {

      try {

        if((mStrMsg = mBufferedReader.readLine())!=null) {

          mStrMsg += “\n”;

          mHandler.sendMessage(mHandler.obtainMessage());

        }

      } catch(Exception e) { }

    }

  }

};

 

Handler mHandler = new Hander(){

  super.handleMessage(msg);

  try {

    mMsgLabel.append(mstrMsg);

  } catch(Exception e) { }

}