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package project.robot.network;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

import project.robot.BluetoothConnection;
import android.os.AsyncTask;

public class TCPServer extends AsyncTask<Void, Integer, Void> {
    int port;               //Port on which server is running
    String clientIP;        //IP address of remote client
    ServerSocket serverSocket;  //Server Socket
    Socket clientSocket;    //Socket connected to client
    DataOutputStream out;   //Output stream object to send data
    DataInputStream in;         //Input Stream object to receive data

    boolean flag;
    boolean videoFlag;  //Used to toggle video
    private VideoThread vthread;    //Video Thread Object

    public static BluetoothConnection conn;

    /*
     * Starts a TCP Server which listens to incoming connections
     */
    public TCPServer(int port) {
        this.port = port;
        videoFlag = false;
        vthread = null;
    }

    @Override
    protected Void doInBackground(Void... arg0) {
        int msg;    

        //Initiating server socket
        try {
            serverSocket = new ServerSocket(port);
            flag = true;
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            System.out.println("Tcpserver: unable to bind socket");
            e1.printStackTrace();
            flag = false;
        }

        System.out.println("TCPServer: Server started");

        while(flag) {
            try {
                //Accepting incoming connection
                clientSocket = serverSocket.accept();
                clientIP = clientSocket.getInetAddress().getHostAddress();
                System.out.println("TCPServer: Connected to client at " + clientIP);

                //Getting input and output streams
                in = new DataInputStream(clientSocket.getInputStream());
                out = new DataOutputStream(clientSocket.getOutputStream());
                msg = 1;

                //Start VideoThread
                try {
                    vthread = new VideoThread(clientIP);
                    vthread.startVideo();
                    System.out.println("TCPServer: Video started");
                    videoFlag = true;
                } catch (Exception e) {
                    e.printStackTrace();
                    vthread = null;
                    System.out.println("TCPServer: Error while starting video");
                }

                //Reading input commands and signaling processing function
                while(flag && msg != 0) {
                    msg = in.readInt();
                    publishProgress(msg);
                }

                //Stopping video streaming if running
                if(vthread != null) {
                    vthread.stopVideo();
                    vthread = null;
                }
                System.out.println("TCPServer: Video stopped");

                //Closing Connection to client
                clientSocket.close();
                clientSocket = null;
                System.out.println("TCPServer: Closed connection to host at " + clientIP);
                clientIP = "null";

            } catch (IOException e) {
                if(clientSocket != null) {
                    clientSocket = null;
                }
                flag = false;
                System.out.println("TCPServer: Error while accepting or closing client connection");
            }
        }

        //Closing serverSocket
        if(serverSocket != null) {
            try {
                serverSocket.close();
                System.out.println("TCPServer: Server Socket Closed");
            } catch (IOException e) {
                e.printStackTrace();
                System.out.println("TCPServer: Error while closing socket");
            }
            serverSocket = null;
        }

        System.out.println("TCPServer: Server stopped");
        return null;
    }

    private void sendSignal(int signal) {
        if(conn != null)
            conn.send(signal);
        else
            System.out.println("TCPServer: null conn, can't send value");
    }


    @Override
    protected void onProgressUpdate(Integer... integers) {
        //Method is called every time a publishProgress is called from doInBackground
        for(Integer integer : integers) {
            System.out.println("TCPServer: Message received - " + integer);
            switch(integer) {
            case 1:
                //Enable SMS service
                if(vthread != null)
                    vthread.msgFlag = true;
                break;
            case 2:
                //Move backward
                sendSignal(2);
                break;
            case 4:
                //Move left
                sendSignal(4);
                break;
            case 5:
                //Stop
                sendSignal(5);
                break;
            case 6:
                //Move right
                sendSignal(6);
                break;
            case 7:
                //Buzzer toggle
                sendSignal(7);
            case 8:
                //Move forward
                sendSignal(8);
                break;
            case 9:
                //Toggle Video
                toggleVideo();
                break;
            default:
                System.out.println("TCPServer: Unrecognized instruction : " + integers[0]);
                break;
            }
        }
    }

    /*
     * Toggles video streaming state
     * if it was on then it will stop it
     * else it will start video streaming
     */
    private void toggleVideo() {
        //If videoFlag is true then stop Video else start video
        if(vthread==null)
            return;

        if(vthread.videoStream) {
            vthread.videoStream = false;
            System.out.println("TCPServer: Video streamming stopped");
        } else {
            System.out.println("TCPServer: Video streamming started");
            vthread.videoStream = true;
        }
    }


    /*
     * `s the server process
     */
    public void stop() {
        System.out.println("TCPServer: Stopping server");
        flag = false;

        //Stopping video if it is running
        if(vthread != null) {
            vthread.stopVideo();
            vthread = null;
        }
        System.out.println("TCPServer: Video stopped");

        //Closing server socket
        if(serverSocket != null) {
            try {
                serverSocket.close();
                System.out.println("TCPServer: Server Socket Closed");
            } catch (IOException e) {
                e.printStackTrace();
                System.out.println("TCPServer: Error while closing socket");
            }
            serverSocket = null;
        }
    }
}

请有人告诉我 telnet 是如何工作的（或者告诉我在哪里可以找到有关该教程的教程）。我得到了上面的代码。我必须将上面的代码（适用于蓝牙）更改为 telnet 代码（适用于 wifi）。

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1 回答 1

3

你的问题有点奇怪，就像问“浏览器教程”，显示下载网页的代码，并询问浏览器的工作原理。

Telnet 只是一个可以连接到服务器并发送接收文本的应用程序（如浏览器）。这段代码也是一个连接到服务器并发送接收信息的应用程序（快速浏览后，主要是整数）。

很多代码主要处理建立连接和传递参数。您会感兴趣的是数据连接：

            //Getting input and output streams
            in = new DataInputStream(clientSocket.getInputStream());
            out = new DataOutputStream(clientSocket.getOutputStream());

稍后的

            //Reading input commands and signaling processing function
            while(flag && msg != 0) {
                msg = in.readInt();
                publishProgress(msg);
            }

然后

private void sendSignal(int signal) {
    if(conn != null)
        conn.send(signal);
    else
        System.out.println("TCPServer: null conn, can't send value");
}

您应该首先了解 Java 中的 Socket 编程（此处为教程）。在你理解了这一点之后，你就会明白为什么你的问题有点奇怪了。您还可以开始弄清楚如何编写代码以使用其他协议进行连接。是的，在编写代码之前，您可以先使用 telnet 手动尝试。

如果你真的需要“telnet 教程”，你可以下载任何使用纯文本连接的 RFC，然后在 telnet 上模拟协议。HTTP、FTP、SMTP 和 IRC 都很容易上手。尝试使用 telnet 发送电子邮件。

于 2012-05-31T06:31:04.510 回答