http://www.frank-buss.de/echoservlet/index.html

ho trovato questo codice interessante ...

copiando lo zip nella root di tomcat , riesco a farlo funzionare , solo che devo riuscirci a lavorare , su eclipse o netbeans ...

Solo che a creare una Applet e una servlet ... la Servlet non viene compilata ...


codice:
import java.io.*;

import javax.servlet.ServletException;
import javax.servlet.http.*;

/**
 * Simple demonstration for an Applet <-> Servlet communication.
 */
public class EchoServlet extends HttpServlet {
	/**
	 * Get a String-object from the applet and send it back.
	 */
	public void doPost(
		HttpServletRequest request,
		HttpServletResponse response)
		throws ServletException, IOException {
		try {
			response.setContentType("application/x-java-serialized-object");

			// read a String-object from applet
			// instead of a String-object, you can transmit any object, which
			// is known to the servlet and to the applet
			InputStream in = request.getInputStream();
			ObjectInputStream inputFromApplet = new ObjectInputStream(in);
			String echo = (String) inputFromApplet.readObject();

			// echo it to the applet
			OutputStream outstr = response.getOutputStream();
			ObjectOutputStream oos = new ObjectOutputStream(outstr);
			oos.writeObject(echo);
			oos.flush();
			oos.close();

		} catch (Exception e) {
			e.printStackTrace();
		}
	}

}

---------

La parte interessante di EchoServerlet
	/**
	 * Get a connection to the servlet.
	 */
	private URLConnection getServletConnection()
		throws MalformedURLException, IOException {

		// Connection zum Servlet öffnen
		URL urlServlet = new URL(getCodeBase(), "echo");
		URLConnection con = urlServlet.openConnection();

		// konfigurieren
		con.setDoInput(true);
		con.setDoOutput(true);
		con.setUseCaches(false);
		con.setRequestProperty(
			"Content-Type",
			"application/x-java-serialized-object");

		// und zurückliefern
		return con;
	}

	/**
	 * Send the inputField data to the servlet and show the result in the outputField.
	 */
	private void onSendData() {
		try {
			// get input data for sending
			String input = inputField.getText();

			// send data to the servlet
			URLConnection con = getServletConnection();
			OutputStream outstream = con.getOutputStream();
			ObjectOutputStream oos = new ObjectOutputStream(outstream);
			oos.writeObject(input);
			oos.flush();
			oos.close();

			// receive result from servlet
			InputStream instr = con.getInputStream();
			ObjectInputStream inputFromServlet = new ObjectInputStream(instr);
			String result = (String) inputFromServlet.readObject();
			inputFromServlet.close();
			instr.close();

			// show result
			outputField.setText(result);

		} catch (Exception ex) {
			ex.printStackTrace();
			exceptionArea.setText(ex.toString());
		}
	}
}
Se compilo separatamente la Servlet mi da questo risultato

codice:
messageHTTP method GET is not supported by this URL

descriptionThe specified HTTP method is not allowed for the requested resource (HTTP method GET is not supported by this URL).
e quando lancio la applet , la carica anche , però quando faccio per inviare la stringa con echoApplet , mi da questa eccezione

codice:
java.net.UnknownServiceException: protocol doesn't support output
        at java.net.URLConnection.getOutputStream(URLConnection.java:785)
        at EchoApplet.onSendData(EchoApplet.java:105)
        at EchoApplet.access$000(EchoApplet.java:10)
        at EchoApplet$1.actionPerformed(EchoApplet.java:46)
        at java.awt.Button.processActionEvent(Button.java:388)
        at java.awt.Button.processEvent(Button.java:356)
        at java.awt.Component.dispatchEventImpl(Component.java:4050)
        at java.awt.Component.dispatchEvent(Component.java:3885)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:176)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)

Qualcuno ha qualche idea ???

grazie !