Question

I’m developing a client-server app where the server is C++ and the client is Java.

To communicate them, I use sockets. Now, I can transfer sucessfully Strings via the socket with this:

Client side:

public void serializeAndSendMessage(String msg) {
    try {
        os.write( msg.getBytes() );
        os.flush();
    }
    catch ( Exception e ) {
        e.printStackTrace();
    }
}

Server side:

char recvbuf[DEFAULT_BUFLEN];
int iResult = recv(ClientSocket, recvbuf, recvbuflen, 0);
    if (iResult > 0) {
        printf("Bytes received: %d\n", iResult);
        recvbuf[iResult] = 0; //set the end of the msg

How can I pass other data, like a Double or an Int? Is it possible to get a Double into a String, and then convert it back in the C++ server from char to Double?

Thanx.

Answer 1

You really want something like Google ProtocolBuffers which takes care of the serialization and deserialization of arbitrary data structures in a cross-platform and cross-language manner.

There are other libraries providing an alternative to ProtoBuf such as Apache thrift (and some of which add the networking which ProtoBuf is missing). That said, ProtoBuf is a fine choice as it is mature, used by Google themselves and has Java and C++ as core languages with first-tier support.