使用Socket处理跨进程的实时聊天

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Socket是套接字, 网络通信经常使用的方法, 分为TCP和UDP两种模式, 需要网络权限, 当然也可以应用于跨进程通信. 本文通过一个简易的Android聊天程序, 熟悉Socket的使用方法.



本文源码的GitHub下载地址

逻辑: 客户端向服务端发送数据, 服务端收到后返回客户端数据.

Server

Socket处理属于网络请求, 需要在其他线程中使用, 不能应用于主线程.

new Thread(new TcpServer()).start();

TCP服务的Socket链接. 设置Socket的端口号

ServerSocket(PORT)

, 不断循环的接收数据

serverSocket.accept()

, 在

responseClient()

方法处理数据.

private class TcpServer implements Runnable {
@Override public void run() {
ServerSocket serverSocket = null;
try {
serverSocket = new ServerSocket(PORT);
} catch (IOException e) {
Log.e(TAG, "建立链接失败, 端口:" + PORT);
e.printStackTrace();
return; // 链接建立失败直接返回
}

while (!mIsServiceDestroyed) {
try {
final Socket client = serverSocket.accept();
Log.e(TAG, "接收数据");
new Thread() {
@Override public void run() {
try {
responseClient(client);
} catch (IOException e) {
e.printStackTrace();
}
}
}.start();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

mIsServiceDestroyed

用于判断服务器是否存活, 防止内存泄露.

处理Socket数据, 使用

BufferedReader

读取数据, 使用

PrintWriter

写入数据, 循环检测, 结束时关闭缓存和Socket.

private void responseClient(Socket client) throws IOException {
// 接收客户端消息
BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));

// 向客户端发送消息
PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(client.getOutputStream())), true);
out.println("欢迎欢迎, 我是Spike!");
while (!mIsServiceDestroyed) {
String str = in.readLine();
Log.e(TAG, "信息来自: " + str);
if (str == null) {
break;
}

int i = new Random().nextInt(mDefinedMessages.length);
String msg = mDefinedMessages[i];
out.println(msg);
Log.e(TAG, "发送信息: " + msg);
}

System.out.println("客户端退出");

// 关闭通信
close(out);
close(in);
client.close();
}

服务器使用单独线程, 模拟跨进程通信.

<service
android:name=".TCPServerService"
android:process=":remote"/>

需要申请网络权限, 连网和访问网络状态.

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

Client

客户端, 向服务器发送数据, 并接收服务器返回的数据.

启动服务, 连接TCP服务器.

Intent intent = new Intent(this, TCPServerService.class);
startService(intent);

new Thread(new Runnable() {
@Override public void run() {
connectTCPServer();
}
}).start();

尝试连接服务器, 每隔1秒进行重试, 并初始化发送缓存

PrintWriter

.

Socket socket = null;

// 不停重试直到连接成功为止
while (socket == null) {
try {
socket = new Socket("localhost", TCPServerService.PORT);
mClientSocket = socket;
mPrintWriter = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
mHandler.sendEmptyMessage(MESSAGE_SOCKET_CONNECTED);
Log.e(TAG, "服务器连接成功");
} catch (IOException e) {
SystemClock.sleep(1000);
Log.e(TAG, "连接TCP服务失败, 重试...");
}
}

成功后, 循环调用, 监听

BufferedReader

, 是否有数据返回.

BufferedReader br = new BufferedReader(
new InputStreamReader(socket.getInputStream()));
while (!MainActivity.this.isFinishing()) {
String msg = br.readLine();
Log.e(TAG, "收到信息: " + msg);
if (msg != null) {
String time = new SimpleDateFormat("HH:mm:ss", Locale.ENGLISH).format(System.currentTimeMillis());
String showedMsg = "server " + time + ":" + msg + "\n";
mHandler.obtainMessage(MESSAGE_RECEIVE_NEW_MSG, showedMsg)
.sendToTarget();
}
}

Handler处理数据, 分为连接成功和获取数据两种情况.

private Handler mHandler = new Handler() {
@Override public void handleMessage(Message msg) {
switch (msg.what) {
case MESSAGE_RECEIVE_NEW_MSG:
mTvContent.setText(
String.valueOf(mTvContent.getText().toString() + msg.obj));
break;
case MESSAGE_SOCKET_CONNECTED:
mBSend.setEnabled(true);
break;
default:
break;
}
}
};

点击按钮发送数据, 直接在PrintWriter中写入, 即可.

public void sendMessage(View view) {
String msg = mEtMessage.getText().toString();
if (!TextUtils.isEmpty(msg) && mPrintWriter != null) {
mPrintWriter.println(msg);
mEtMessage.setText("");
String time = new SimpleDateFormat("HH:mm:ss", Locale.ENGLISH).format(System.currentTimeMillis());
String showedMsg = "self " + time + ":" + msg + "\n";
mTvContent.setText(String.valueOf(mTvContent.getText() + showedMsg));
}
}

当我们向服务端发送数据时, 就会获取服务端的返回, 模拟聊天效果.

效果



Socket作为经典的网络通信方式, 有很多应用, 也可以实现跨进程通信, 希望能熟练掌握.

OK, that’s all! Enjoy it!