client.java

j2me中udp传输的功能实验室试过感觉不错！！！！

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import java.io.IOException;
import javax.microedition.io.Connector;
import javax.microedition.io.Datagram;
import javax.microedition.io.UDPDatagramConnection;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

/**
 * @author Administrator
 */
public class Client extends MIDlet implements CommandListener{
        private Display ds;
    private Form fm=new Form("Client");
    private TextField tf= new TextField("输入内容","",255,TextField.ANY);
    private Command cmdSend= new Command("Send",Command.SCREEN,1);
    
      private UDPDatagramConnection udc;
    private Datagram dg;
    
   private final int MAX =255 ;//定义一个空间给接受的数据报最大字节数
    public void startApp() {
            ds= Display.getDisplay(this);
        ds.setCurrent(fm);
        fm.append(tf);
       fm.addCommand(cmdSend);
       fm.setCommandListener(this);
        
        try {
        udc = (UDPDatagramConnection) Connector.open("datagram://192.168.0.101:9999");
      
     } catch (IOException ex) {
            ex.printStackTrace();
        }
       
    }
    public void commandAction(Command c,Displayable d){
        if(c==cmdSend){
            String str=tf.getString();  //发送数据报
    try {
                dg = udc.newDatagram(str.getBytes(), str.getBytes().length);
                
                new ReceiveThread().start();
                udc.send(dg);//送给服务器端
            } catch (IOException ex) {
                ex.printStackTrace();
            }
 
        }
    }
    class ReceiveThread extends Thread{
        public void run(){
            while(true){
                         //接受数据报
      try{
                dg= udc.newDatagram(MAX);
        udc.receive(dg);
        byte[] data=dg.getData();
        fm.append(new String(data,0,dg.getLength())); 
      }catch(Exception e){
          e.printStackTrace();
      }
            }
        }
    }

    public void pauseApp() {
    }

    public void destroyApp(boolean unconditional) {
    }
}