datagramsender.java

Java ME手机应用开发大全一书的配套光盘上的源码

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

public class DatagramSender extends MIDlet{
  // MIDlet构造程序
  public DatagramSender() {}

  // 被应用程序管理器调用来启动MIDlet。
  public void startApp() 
	  {
   try {
	        //建立并打开数据报连接
            DatagramConnection sender = 
                    (DatagramConnection)Connector.open("datagram://localhost:5555");
            //声明要发送的测试数据的长度
			int length=10;
			//声明要发送数据的数组
            byte[] buffer = new byte[length];
            for (int i = 0; i < length; i++) {
                buffer[i] = (byte)('0' + (i % 10));
            }
			//构造Datagram对象
            Datagram dgram = sender.newDatagram(buffer, buffer.length);
			//发送数据报
            sender.send(dgram);
            
            // 等待数据报返回
            for (int i = 0; i < length; i++) {
                buffer[i] = (byte)0;
            }
			//接收客户端发回的数据
            sender.receive(dgram);
            length = dgram.getLength();
            System.out.println("Received return packet, length is " + length);
            
            // 显示客户端发回的数据报中的数据
            for (int i = 0; i < length; i++) {
                System.out.print(buffer[i] + " ");
            }
            System.out.println();
        } 
		catch (IOException ex) {
            System.out.println("IOException: " + ex);
        }
  

  }
  public void pauseApp() {
  }
  public void destroyApp(boolean unconditional) {
  }


   
}