通过TCP套接字发送和接收数据的问题

Question

我在尝试使用我的android（Basic4Android）与运行.net TCP服务器的PC进行通信时出现问题。我需要能够有按钮发送4byte命令到服务器并接收回应。当我在android上运行程序时，服务器确实连接并接收到字符串“INFO”，但是直到我重新启动程序并且它只是再次发送命令“INFO”时才发送或接收任何内容。当我按下按钮发送命令时，我没有遇到任何错误，但服务器从未收到任何内容。该服务器是一个用VB.NET编写的Windows窗体多线程程序。我写了一个VB.NET客户端程序，该程序可以作为我正在尝试执行的一个示例。这是我第一次尝试Android应用程序，到目前为止我只是修改了我在教程中找到的网络示例。

的代码如下... 感谢

Sub Process_Globals 
    Dim Socket1 As Socket 
End Sub 

Sub Globals 
    Dim Button_ARM As Button 
    Dim Button_STAY As Button 
    Dim Button_AUTO As Button 
    Dim Button_OFF As Button 
    Dim Label_Received As Label 
    Dim Label_Sent As Label 
    Dim tr As TextReader 
    Dim tw As TextWriter 
    Dim sb As StringBuilder 
End Sub 

Sub Activity_Create(FirstTime As Boolean) 
    Activity.LoadLayout("Alarm_Control") 
    Socket1.Initialize("Socket1") 
    Socket1.Connect("#.#.#.#" , 8000, 20000) 'My IP address goes here 
End Sub 

Sub Socket1_Connected (Successful As Boolean) 
    If Successful = False Then 
     Msgbox(LastException.Message, "Error connecting") 
     Return 
    End If 
    tr.Initialize(Socket1.InputStream) 
    tw.Initialize(Socket1.OutputStream) 
    tw.WriteLine("INFO") 
    Label_Sent.Text = "Sent INFO" 
    tw.Flush  
    sb.Initialize 
    sb.Append(tr.ReadLine) 
    Label_Received.Text = sb.ToString 
    'Socket1.Close 
End Sub 

Sub Button_ARM_Click 
    tw.WriteLine("O001") 
    tw.Flush 
    Label_Sent.Text = "Sent O001" 
End Sub 

Sub Button_STAY_Click 
    tw.WriteLine("O002") 
    tw.Flush 
    Label_Sent.Text = "Sent O002" 
End Sub 

Sub Button_OFF_Click 
    tw.WriteLine("O000") 
    tw.Flush 
    Label_Sent.Text = "Sent O000" 
End Sub 

Answer 1

你是如何在服务器端读取数据？请注意，TextWriter.WriteLine写入一个以chr（10）结尾的行。确保你没有等待chr（13）和chr（10）。

Answer 2

我在列表程序调用的线程中使用networkStream.read和networkStream.write。 vb.net客户端程序与vb.net服务器正常工作。

Public Sub handlerThread() 
    Dim handlerSocket As Socket 
    handlerSocket = alSockets(alSockets.Count - 1) 
    Dim networkStream As NetworkStream = New NetworkStream(handlerSocket) 
    Dim bytes(4) As Byte 
    networkStream.Read(bytes, 0, CInt(4))  ' Read the stream into 4-byte array 
    Dim clientdata As String = Encoding.ASCII.GetString(bytes) 
    Label_Received.Text = clientdata 
    Dim responseString As String = "Received " + clientdata 
    Dim sendBytes As [Byte]() = Encoding.ASCII.GetBytes(responseString) 
    networkStream.Write(sendBytes, 0, sendBytes.Length) 
    Label_Sent.Text = responseString 
    handlerSocket = Nothing 
End Sub 

Answer 3

Chr（10）在这里似乎没有问题。 我在使用这个Java服务器代码相同的问题：

import java.io.*; 
import java.net.*; 

public class ec192 { 
    public static void main(String[] args) throws IOException { 

    Socket echoSocket = null; 
    PrintWriter out = null; 
    BufferedReader in = null; 

    try { 

    echoSocket = new Socket("192.168.0.45", 2222); 
     out = new PrintWriter(echoSocket.getOutputStream(), true); 
     in = new BufferedReader(new InputStreamReader(
           echoSocket.getInputStream())); 
    } catch (UnknownHostException e) { 
     System.err.println("Don't know about host: taranis."); 
     System.exit(1); 
    } catch (IOException e) { 
     System.err.println("Couldn't get I/O for " 
         + "the connection to: 2222 taranis."); 
     System.exit(1); 
    } 

BufferedReader stdIn = new BufferedReader(
           new InputStreamReader(System.in)); 
String userInput; 

    while ((userInput = stdIn.readLine()) != null) { 
    out.println(userInput); 
    System.out.println("echo: " + in.readLine()); 
} 

out.close(); 
in.close(); 
stdIn.close(); 
echoSocket.close(); 
    } 
}