Question

我创建了一个TCP服务器（PC）客户端（Android）应用程序。我将客户端连接到服务器，但是当我重新启动我的Android应用程序时，我无法建立连接。如何处理这个，所以当我重新启动Android应用程序时，它连接到服务器的端口？服务器是VB.net和客户端java for android

    Sub Main()
    Dim serverSocket As New TcpListener(8888)
    Dim requestCount As Integer
    Dim clientSocket As TcpClient
    serverSocket.Start()
    msg("Server Started")
    clientSocket = serverSocket.AcceptTcpClient()
    msg("Accept connection from client")
    requestCount = 0
    Dim flag As Boolean = True

    While (flag = True)
        Try
            requestCount = requestCount + 1
            Dim networkStream As NetworkStream = _
                    clientSocket.GetStream()
            Dim bytesFrom(10024) As Byte
            networkStream.Read(bytesFrom, 0, CInt(clientSocket.ReceiveBufferSize))
            Dim dataFromClient As String = _
                    System.Text.Encoding.ASCII.GetString(bytesFrom)
            msg("Data from client -  " + dataFromClient)
            Dim serverResponse As String = _
                "Server response " + Convert.ToString(requestCount)
            Dim sendBytes As [Byte]() = _
                Encoding.ASCII.GetBytes(serverResponse)
            networkStream.Write(sendBytes, 0, sendBytes.Length)
            networkStream.Flush()
            msg(serverResponse)
        Catch ex As Exception
            MsgBox(ex.ToString)
        End Try
    End While

    clientSocket.Close()
    serverSocket.Stop()
    msg("exit")
    Console.ReadLine()
End Sub

Sub msg(ByVal mesg As String)
    mesg.Trim()
    Console.WriteLine(" >> " + mesg)
End Sub

public class connectTask extends AsyncTask<String, String, TCPClient> {

    @Override
    protected TCPClient doInBackground(String... message) {

        // we create a TCPClient object and
        mTcpClient = new TCPClient(new TCPClient.OnMessageReceived() {
            @Override
            // here the messageReceived method is implemented
            public void messageReceived(String message) {
                // this method calls the onProgressUpdate
                publishProgress(message);
            }
        });
        mTcpClient.run();
        return null;
    }

public class TCPClient {
private String serverMessage;
public static final String SERVERIP = "192.168.1.65"; //your computer IP address
public static final int SERVERPORT = 4444;
private OnMessageReceived mMessageListener = null;
private boolean mRun = false;

PrintWriter out;
BufferedReader in;

/**
 *  Constructor of the class. OnMessagedReceived listens for the messages received from server
 */
public TCPClient(OnMessageReceived listener) {
    mMessageListener = listener;
}

/**
 * Sends the message entered by client to the server
 * @param message text entered by client
 */
public void sendMessage(String message){
    if (out != null && !out.checkError()) {
        out.println(message);
        out.flush();
    }
}

public void stopClient(){
    mRun = false;
}

public void run() {

    mRun = true;

    try {
        //here you must put your computer's IP address.
        InetAddress serverAddr = InetAddress.getByName(SERVERIP);

        Log.e("TCP Client", "C: Connecting...");

        //create a socket to make the connection with the server
        Socket socket = new Socket(serverAddr, SERVERPORT);

        try {

            //send the message to the server
            out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);

            Log.e("TCP Client", "C: Sent.");

           //receive the message which the server sends back
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            //in this while the client listens for the messages sent by the server
            while (mRun) {
                serverMessage = in.readLine();

                if (serverMessage != null && mMessageListener != null) {
                    //call the method messageReceived from MyActivity class
                    mMessageListener.messageReceived(serverMessage);
                }
                serverMessage = null;

            }


            Log.e("RESPONSE FROM SERVER", "S: Received Message: '" + serverMessage + "'");


        } catch (Exception e) {

            Log.e("TCP", "S: Error", e);

        } finally {
            //the socket must be closed. It is not possible to reconnect to this socket
            // after it is closed, which means a new socket instance has to be created.
            socket.close();
            Log.e("Socket","Closed");
        }

    } catch (Exception e) {

        Log.e("TCP", "C: Error", e);

    }

}

Answer 1

TCP可能是最常用的协议，仅仅因为它用于HTTP，POP，SMTP等许多应用程序.TCP是一种协议，可以保证接收方能够准确接收发送方发送的内容 - 这将是没有错误，它将按照正确的顺序，一切都会正常工作。

 try {
        Socket s = new Socket("http://helloandroid.com&quot",80);
} catch (UnknownHostException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
} catch (IOException e) {
        // TODO Auto-generated catch block
       e.printStackTrace();
}

这是一个简单的客户端TCP请求。如果连接成功建立，您可以获得进行通信所需的过程。

现在让我们看一下服务器端示例：

try {
    Boolean end = false;
    ServerSocket ss = new ServerSocket(12345);
    while(!end){
            //Server is waiting for client here, if needed
            Socket s = ss.accept();
            BufferedReader input = new BufferedReader(new InputStreamReader(s.getInputStream()));
            PrintWriter output = new PrintWriter(s.getOutputStream(),true); //Autoflush
            String st = input.readLine();
            Log.d("Tcp Example", "From client: "+st);
            output.println("Good bye and thanks for all the fish :)");
            s.close();
            if ( STOPPING conditions){ end = true; }
    }
ss.close();


} catch (UnknownHostException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

最后看到客户端：

 try {
    Socket s = new Socket("localhost",12345);

    //outgoing stream redirect to socket
    OutputStream out = s.getOutputStream();

    PrintWriter output = new PrintWriter(out);
    output.println("Hello Android!");
    BufferedReader input = new BufferedReader(new InputStreamReader(s.getInputStream()));

    //read line(s)
    String st = input.readLine();
    . . .
    //Close connection
    s.close();


} catch (UnknownHostException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

就是这样。希望你发现这会有所帮助。

Android TCP服务器客户端

1 个答案: