Sending data from Java to C using socket programming
i am making a program that sends a string from a Java client to a C server using WinSock2. I am using DataOutputStream to send the data through the socket.
The C server, acknowledges the bytes received, but when i try accessing the data, nothing is displayed.
SERVER
Socket socket = null;
DataOutputStream dataOutputStream = null;
DataInputStream dataInputStream = null;
try {
socket = new Socket("10.40.0.86", 2007);
dataOutputStream = new DataOutputStream(socket.getOutputStream());
dataInputStream = new DataInputStream(socket.getInputStream());
//dataOutputStream.writeUTF("How are you doing let us see what is the maximum possible length that can be supported by the protocal");
String line = "hey";
dataOutputStream.writeUTF(line);
dataOutputStream.flush();
//System.out.println(dataInputStream.readLine());
System.out.println((String)dataInputStream.readLine().replaceAll("[^0-9]",""));
//System.out.println(dataInputStream.readInt());
//System.out.println(dataInputStream.readUTF());
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
CLIENT
if (sock开发者_如何转开发et_type != SOCK_DGRAM)
{
retval = recv(msgsock, Buffer, sizeof(Buffer), 0);
printf("Server: Received datagram from %s\n", inet_ntoa(from.sin_addr));
}
output
Server: Received 5 bytes, data "" from client
BUFFER :
Server: Echoing the same data back to client...
BUFFER :
Server: send() is OK.
Your C code needs to understand the data format written by writeUTF() (see the Javadoc), or else more simply you need to use write(char[]) or write(byte[]) at the Java end.
Here is how I solved this :-)
dataOutputStream.write(line.getBytes());
Or to be more specific here is my code:
out.write(("Hello from " + client.getLocalSocketAddress()).getBytes());
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