datagramclient.java

《精通JAVA手机游戏与应用程序设计》随书光盘

package DatagramExample;

import javax.microedition.midlet.*;
import javax.microedition.io.*;
import javax.microedition.lcdui.*;

import java.io.*;

public class DatagramClient extends MIDlet implements Runnable, CommandListener {
	private Display display;

	private Form f;

	private StringItem si;

	private TextField tf;

	private boolean stop;

	private Command sendCommand = new Command("Send", Command.ITEM, 1);

	private Command exitCommand = new Command("Exit", Command.EXIT, 1);

	DatagramConnection dc;

	public DatagramClient() {

		display = Display.getDisplay(this);
		f = new Form("Socket Server");
		si = new StringItem("Status:", " ");
		tf = new TextField("Send:", "", 100, TextField.ANY);
		f.append(tf);
		f.append(si);

		f.addCommand(exitCommand);
		f.addCommand(sendCommand);
		f.setCommandListener(this);
		display.setCurrent(f);

		Thread t = new Thread(this);
		t.start();

	}

	protected void startApp() {
		// TODO 自动生成方法存根

	}

	protected void pauseApp() {
		// TODO 自动生成方法存根

	}

	protected void destroyApp(boolean arg0) {
		// TODO 自动生成方法存根

	}

	public void run() {
		// TODO 自动生成方法存根

		try {

			dc = (DatagramConnection) Connector
					.open("datagram://localhost:5555");

			si.setText("Connected to server");

			while (true) {
				Datagram dg = dc.newDatagram(100);
				dc.receive(dg);
				// Have we actually received something or
				// is this just a timeout ?
				if (dg.getLength() > 0) {
					si.setText("Message received - "
							+ new String(dg.getData(), 0, dg.getLength()));
				}
			}

		} catch (ConnectionNotFoundException cnfe) {
			Alert a = new Alert("Client", "Please run Server MIDlet first",
					null, AlertType.ERROR);
			a.setTimeout(Alert.FOREVER);
			display.setCurrent(a);
		} catch (IOException ioe) {
			ioe.printStackTrace();
		}

	}

	public void stop() {

	}

	public void commandAction(Command c, Displayable d) {
		// TODO 自动生成方法存根
		if (c == sendCommand) {

			try {
				byte[] bytes = tf.getString().getBytes();
				Datagram dg = null;
				// Are we a sender thread for the client ? If so then there's
				// no address parameter

				dg = dc.newDatagram(bytes, bytes.length);

				dc.send(dg);
			} catch (Exception ioe) {
				ioe.printStackTrace();
			}

		}
		if (c == exitCommand) {

			destroyApp(false);
			notifyDestroyed();
		}

	}

}