非常简单的 TCP 客户端 [英] Really simple TCP client
问题描述
我想用我的应用程序输入我的服务器的 url，例如http://192.168.1.8/ 和端口，例如1234.当我的服务器收到 TCP 请求消息时，它会发回一个文件(服务器已经实现).
I want with my app to enter in the url of my server e.g. http://192.168.1.8/ and the port e.g. 1234.
When my server receives the TCP Request message, it sends back a file (the server is already implemented).
我认为我不需要像 AsyncTask 这样复杂的东西，因为我不想保持连接.收到服务器的答复，我的连接必须关闭.
I think that I don't need something complicated like an AsyncTask, as I do not want to keep the connection. Receiving the answer from the server, my connection must be closed.
非常感谢任何有关前进方向或提示的指示.
Any indication for a way forward or a tip is highly appreciated.
推荐答案
这是一个简单的 TCP 客户端，它使用我基于 本教程(本教程的代码也可以在在此 GitHub 存储库中).
Here is a simple TCP client that uses Sockets that I got working based on code in this tutorial (the code for the tutorial can also be found in this GitHub repository).
请注意，此代码适用于在客户端和服务器之间来回发送字符串，通常采用 JSON 格式.
Note that this code is geared to sending strings back and forth between the client and server, usually in JSON format.
这是TCP客户端代码:
Here is the TCP client code:
import android.util.Log;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
public class TcpClient {
public static final String TAG = TcpClient.class.getSimpleName();
public static final String SERVER_IP = "192.168.1.8"; //server IP address
public static final int SERVER_PORT = 1234;
// message to send to the server
private String mServerMessage;
// sends message received notifications
private OnMessageReceived mMessageListener = null;
// while this is true, the server will continue running
private boolean mRun = false;
// used to send messages
private PrintWriter mBufferOut;
// used to read messages from the server
private BufferedReader mBufferIn;
/**
* 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(final String message) {
Runnable runnable = new Runnable() {
@Override
public void run() {
if (mBufferOut != null) {
Log.d(TAG, "Sending: " + message);
mBufferOut.println(message);
mBufferOut.flush();
}
}
};
Thread thread = new Thread(runnable);
thread.start();
}
/**
* Close the connection and release the members
*/
public void stopClient() {
mRun = false;
if (mBufferOut != null) {
mBufferOut.flush();
mBufferOut.close();
}
mMessageListener = null;
mBufferIn = null;
mBufferOut = null;
mServerMessage = null;
}
public void run() {
mRun = true;
try {
//here you must put your computer's IP address.
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
Log.d("TCP Client", "C: Connecting...");
//create a socket to make the connection with the server
Socket socket = new Socket(serverAddr, SERVER_PORT);
try {
//sends the message to the server
mBufferOut = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);
//receives the message which the server sends back
mBufferIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
//in this while the client listens for the messages sent by the server
while (mRun) {
mServerMessage = mBufferIn.readLine();
if (mServerMessage != null && mMessageListener != null) {
//call the method messageReceived from MyActivity class
mMessageListener.messageReceived(mServerMessage);
}
}
Log.d("RESPONSE FROM SERVER", "S: Received Message: '" + mServerMessage + "'");
} 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();
}
} catch (Exception e) {
Log.e("TCP", "C: Error", e);
}
}
//Declare the interface. The method messageReceived(String message) will must be implemented in the Activity
//class at on AsyncTask doInBackground
public interface OnMessageReceived {
public void messageReceived(String message);
}
}
然后，在您的 Activity 中声明一个 TcpClient 作为成员变量:
Then, declare a TcpClient as a member variable in your Activity:
public class MainActivity extends Activity {
TcpClient mTcpClient;
//............
然后，使用 AsyncTask 连接到您的服务器并在 UI 线程上接收响应(请注意，从服务器接收的消息在 AsyncTask 中的 onProgressUpdate() 方法覆盖中处理):
Then, use an AsyncTask for connecting to your server and receiving responses on the UI thread (Note that messages received from the server are handled in the onProgressUpdate() method override in the AsyncTask):
public class ConnectTask extends AsyncTask<String, String, TcpClient> {
@Override
protected TcpClient doInBackground(String... message) {
//we create a TCPClient object
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;
}
@Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
//response received from server
Log.d("test", "response " + values[0]);
//process server response here....
}
要开始连接到您的服务器，请执行 AsyncTask:
To start the connection to your server, execute the AsyncTask:
new ConnectTask().execute("");
然后，向服务器发送消息:
Then, sending a message to the server:
//sends the message to the server
if (mTcpClient != null) {
mTcpClient.sendMessage("testing");
}
您可以随时关闭与服务器的连接:
You can close the connection to the server at any time:
if (mTcpClient != null) {
mTcpClient.stopClient();
}
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