Send binary file using xml

Question

Hi all,
I've got an application wich currently sends xml messages through sockets between server and client. Now, I'd like to be able of sending binary files (jpegs and other images...) as some content of these files. Is it possible with CDATA? Do you know any URL with an example or something?
thanks a lot!

Answer 1

This is a little example that shows the solution I adopted.
Two classes, a server and a client, execute the server in a given port and the client with "localhost" as ip and the same port as the server.
Ex: java Server 5555
java Client localhost 5555
the code:
import java.net.*;
import java.io.*;
public class Server {
    public static void main(String[] args) {
        ServerSocket serverSocket = null;
        if(args.length!=1){
            System.out.println("ERROR: java Server <port>");
        } else {
               // Create listening socket
               try {
                    serverSocket = new ServerSocket((new Integer(args[0])).intValue());
               } catch (IOException e) {
                    System.out.println("ERROR: not possible to listen on the specified port");
                    System.exit(1);
               // Create wait for connection
               Socket clientSocket = null;
               try {
                    clientSocket = serverSocket.accept();
               } catch (IOException e) {
                    System.err.println("ERROR: Accept failed.");
                    System.exit(1);
               try{
                      // Get the output channel
                    PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
                    // Send a xml message
                    out.print("<?xml version=\"1.0\" encoding=\"UTF-8\"?><FOO><VAR message=\"ugly harcoded XMLmessage\"/></FOO>\0");
                    out.flush();
                    out.close();
                    clientSocket.close();
                    serverSocket.close();
               } catch(IOException IOE){
                    System.out.println("ERROR: on send");
import java.io.*;
import org.w3c.dom.Document;
import java.net.*;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.xml.sax.SAXException;
import org.xml.sax.InputSource;
public class Client {
     public static void handleIncomingMessage(Document doc){
        System.out.println("DO WHAT YOU WANT WITH THE XML!");
    public static void main(String[] args){
        BufferedReader in = null;
        Socket socket = null;
        if(args.length!=2){
            System.out.println("ERROR: java Client <ip> <port>");
        } else {
            String ip = args[0];
            int port = (new Integer(args[1])).intValue();
               // Open a socket to the server
            try {
                    socket = new Socket(ip,port);
               } catch (UnknownHostException e) {
                    System.out.println("ERROR: Unknow host!");
                    System.exit(1);
               } catch (IOException e) {
                    System.out.println("ERROR: I/O error");
                    System.exit(1);
          try {
            // Get the input channel
               in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        } catch (IOException e) {
            System.err.println("ERROR: I/O error");
            System.exit(1);
          // Create a DocumentBuilder to convert the socket's incoming String
        // to a XML parsed Document
          Document XMLmessage =null;
        DocumentBuilder builder = null;
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
          try{
               builder = factory.newDocumentBuilder();
        } catch (ParserConfigurationException PCE) {
            System.out.println(PCE.toString());
          try{
            String messageRead = "";
            char caracter;
            StringBuffer sb = null;
               // Read from the socket until \0
               sb = new StringBuffer();
               caracter =(char)in.read();
               while(caracter != '\0'){
                    sb.append(caracter);
                    caracter = (char)in.read();
               messageRead = sb.toString();
               System.out.println("Recieved: "+messageRead);
            // Parse the read message
               try{
                    XMLmessage = builder.parse(new InputSource((Reader)new StringReader(messageRead)));
                    // Work with it
                    handleIncomingMessage(XMLmessage);
               } catch(IOException IOE){
                    System.out.println(IOE.toString());
               } catch(SAXException SE) {
                    System.out.println(SE.toString());
          } catch(IOException IOE){
               System.out.println("ERROR: I/O error");
}hope it helps!
any comment about the code will be welcome