datagramclient.java

java手机程序开发随书光盘源代码

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

public class DatagramClient extends MIDlet implements CommandListener{

	Display display;
	String serverURL = "datagram://127.0.0.1:5678";
	TextBox input;
	Command exitCmd;
	Command okCmd;

	public DatagramClient(){
		display = Display.getDisplay(this);
		input = new TextBox("送出和接收信息", "", 100, TextField.ANY);
		exitCmd = new Command("退出", Command.EXIT, 1);
		okCmd = new Command("送出", Command.OK, 1);
		input.addCommand(exitCmd);
		input.addCommand(okCmd);
		input.setCommandListener(this);
	}

	public void startApp(){
		display.setCurrent(input);
	}

	public void pauseApp(){
	}

	public void destroyApp(boolean conditional){
	}

	public void commandAction(Command c, Displayable d){
		if( c == exitCmd){
			destroyApp(true);
			notifyDestroyed();
		}
		else if(c == okCmd){
			try{
				sendAndReceive(serverURL);
			}
			catch(Exception ex){}
		}
	}

	void sendAndReceive(String url) throws IOException{
		DatagramConnection con = (DatagramConnection)Connector.open(url);
		Datagram datagramOut = con.newDatagram(100);
		Datagram datagramIn = con.newDatagram(100);

		try{
			/* byte[] out = input.getString().getBytes();
			datagramOut.setData(out, 0, out.length);
			con.send(datagramOut); */
			System.out.println("test5");
			con.receive(datagramIn);
			System.out.println("test2");
			byte[] in = datagramIn.getData();
			String response = new String(in);
			System.out.println(response);
			/* input.insert("\nServer>>", input.getCaretPosition());
			input.insert(response, input.getCaretPosition()); */
			System.out.println("test3");
			display.setCurrent(input);
		}
		finally{
			if(con != null)
				con.close();
		}
	}

}