我希望我的应用输入我服务器的网址，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）。
我认为我不需要像AsyncTask那样复杂的东西，因为我不想保持连接。从服务器接收答案，我的连接必须关闭。
对前进方式或提示的任何指示都表示高度赞赏。
答案 0 :(得分：31)
这是一个简单的TCP客户端，它使用我根据this tutorial中的代码工作的套接字（教程的代码也可以找到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。
这是TCP客户端代码：
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Activity：
中声明一个TcpClient作为成员变量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是在AsyncTask中的onProgressUpdate()方法覆盖中处理的）：
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....
}
要开始与服务器的连接，请执行AsyncTask：
new ConnectTask().execute("");
然后，向服务器发送消息：
//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：
if (mTcpClient != null) {
mTcpClient.stopClient();
}
答案 1 :(得分：5)
感谢您的代码。在我的情况下，我无法接收数据，因为我没有使用基于行的协议。 我写了一个替代实现，它适用于我的特定服务器设置：
在TcpClient.java文件中，＆＃34; run（）＆＃34;命令你应该用下面的代码片段替换
public void run（）{
mRun = true;
try {
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
Log.e("TCP Client", "C: Connecting...");
Socket socket = new Socket(serverAddr, SERVER_PORT);
try {
mBufferOut = new PrintWriter(socket.getOutputStream());
Log.e("TCP Client", "C: Sent.");
mBufferIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
int charsRead = 0; char[] buffer = new char[1024]; //choose your buffer size if you need other than 1024
while (mRun) {
charsRead = mBufferIn.read(buffer);
mServerMessage = new String(buffer).substring(0, charsRead);
if (mServerMessage != null && mMessageListener != null) {
mMessageListener.messageReceived(mServerMessage);}
mServerMessage = null;
}
Log.e("RESPONSE FROM SERVER", "S: Received Message: '" + mServerMessage + "'");
//其余代码没问题，见原文
您的MainActivity.java中的doInBackgroud将收到的消息发布到onProgressUpdate，您可以将其显示在其他对象中，例如TextView的
@Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
Log.d("test", "response " + values[0]);
response.setText(response.getText() + "/n" +values[0]);
}
//＆＃34;响应＆＃34;是函数中声明的TextView对象
public class MainActivity extends AppCompatActivity {
TextView response; //...so on
和功能
protected void onCreate(Bundle savedInstanceState) {
response = (TextView) findViewById(R.id.textView); //..so on
答案 2 :(得分：1)
首先在android清单中为您的应用授予互联网权限
<uses-permission android:name="android.permission.INTERNET"/>
您可以使用AsyncTask轻松发送请求并接收文件
public void send_request() {
send_request sr = new send_request();
sr.execute();
}
class send_request extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... voids) {
try { /*note : ip address must be in Quotation mark*/
/*note : port doesn't need to be inside the Quotation mark*/
Socket s = new Socket(/*ip address :*/"192.168.1.8",/*port :*/ 1234);
PrintWriter printWriter = new PrintWriter(s.getOutputStream());
printWriter.write("your message");
printWriter.flush();
printWriter.close();
s.close();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
public void onPostExecute(final String Data) {
/*Data is what you receive from your server*/
Log.e("my_Data","Data is : " + Data);
}
}
答案 3 :(得分：0)
在TcpClient中尝试以下代码：
public void run() {
mRun = true;
try {
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
Log.e("TCP Client", "C: Connecting...");
Socket socket = new Socket(serverAddr, SERVER_PORT);
try {
mBufferOut = new PrintWriter(socket.getOutputStream());
Log.e("TCP Client", "C: Sent.");
mBufferIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
int charsRead = 0; char[] buffer = new char[2024]; //choose your buffer size if you need other than 1024
while (mRun) {
charsRead = mBufferIn.read(buffer);
mServerMessage = new String(buffer).substring(0, charsRead);
if (mServerMessage != null && mMessageListener != null) {
Log.e("in if---------->>", " Received : '" + mServerMessage + "'");
}
mServerMessage = null;
}
Log.e("-------------- >>", " Received : '" + 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();
Log.e("-------------- >>", "Close socket " );
}
} catch (Exception e) {
Log.e("TCP", "C: Error", e);
}
}
它正常工作。上面其他代码中的这一行会导致错误。
mMessageListener.messageReceived（mServerMessage）;
删除此行，您的应用程序运行良好。您也可以监视您在android studio中的登录。
您可以在Golang中的服务器上使用此代码。这是我的服务器：
package main
import (
"bufio"
"flag"
"fmt"
"net"
"strconv"
)
var addr = flag.String("addr", "", "The address to listen to; default is \"\" (all interfaces).")
var port = flag.Int("port", 37533, "The port to listen on; default is 37533.")
func main() {
flag.Parse()
fmt.Println("Starting server...")
src := *addr + ":" + strconv.Itoa(*port)
listener, _ := net.Listen("tcp", src)
fmt.Printf("Listening on %s.\n", src)
defer listener.Close()
for {
conn, err := listener.Accept()
if err != nil {
fmt.Printf("Some connection error: %s\n", err)
}
go handleConnection(conn)
}
}
func handleConnection(conn net.Conn) {
remoteAddr := conn.RemoteAddr().String()
LocalAddr :=conn.LocalAddr().String()
fmt.Println("Client LocalAddr " + LocalAddr)
fmt.Println("Client connected from " + remoteAddr)
scanner := bufio.NewScanner(conn)
for {
ok := scanner.Scan()
if !ok {
break
}
handleMessage(scanner.Text(), conn)
}
fmt.Println("Client at " + remoteAddr + " disconnected.")
}
func handleMessage(message string, conn net.Conn) {
fmt.Println("> " + message)
if len(message) > 0 {
conn.Write([]byte("This is from Golang.\n"))
fmt.Println("----------> we send it....")
}
}
答案 4 :(得分：0)
最终的部署环境是什么？您的代码指向本地IP。当您将其部署到真实的服务器环境时，事情可能会改变吗？ 如果在托管服务器中启动此代码，请注意NAT问题。这样您将无法获取数据包。 考虑使用更复杂的协议（例如Socket.io可以提供帮助）