Android网络编程之UDP通信模型实例

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

import android.util.Log;

public class UDPServer implements Runnable {

 private static final int PORT = 6000;

 private byte[] msg = new byte[1024];

 private boolean life = true;

 public UDPServer() {
 }

 /**
  * @return the life
  */
 public boolean isLife() {
  return life;
 }

 /**
  * @param life
  *            the life to set
  */
 public void setLife(boolean life) {
  this.life = life;
 }

 @Override
 public void run() {
  DatagramSocket dSocket = null;
  DatagramPacket dPacket = new DatagramPacket(msg, msg.length);
  try {
   dSocket = new DatagramSocket(PORT);
   while (life) {
    try {
     dSocket.receive(dPacket);
     Log.i("msg sever received", new String(dPacket.getData()));
    } catch (IOException e) {
     e.printStackTrace();
    }
   }
  } catch (SocketException e) {
   e.printStackTrace();
  }
 }
}

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;

public class UDPClient {

 private static final int SERVER_PORT = 6000;

 private DatagramSocket dSocket = null;

 private String msg;

 /**
  * @param msg
  */
 public UDPClient(String msg) {
  super();
  this.msg = msg;
 }

 /**
  * 发送信息到服务器
  */
 public String send() {
  StringBuilder sb = new StringBuilder();
  InetAddress local = null;
  try {
   local = InetAddress.getByName("localhost"); // 本机测试
   sb.append("已找到服务器,连接中...").append("/n");
  } catch (UnknownHostException e) {
   sb.append("未找到服务器.").append("/n");
   e.printStackTrace();
  }
  try {
   dSocket = new DatagramSocket(); // 注意此处要先在配置文件里设置权限,否则会抛权限不足的异常
   sb.append("正在连接服务器...").append("/n");
  } catch (SocketException e) {
   e.printStackTrace();
   sb.append("服务器连接失败.").append("/n");
  }
  int msg_len = msg == null ? 0 : msg.length();
  DatagramPacket dPacket = new DatagramPacket(msg.getBytes(), msg_len,
    local, SERVER_PORT);
  try {
   dSocket.send(dPacket);
   sb.append("消息发送成功!").append("/n");
  } catch (IOException e) {
   e.printStackTrace();
   sb.append("消息发送失败.").append("/n");
  }
  dSocket.close();
  return sb.toString();
 }

}

 EditText msg_et = null;
 Button send_bt = null;
 TextView info_tv = null;

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  msg_et = (EditText) findViewById(R.id.msg_et);
  send_bt = (Button) findViewById(R.id.send_bt);
  info_tv = (TextView) findViewById(R.id.info_tv);

  // 开启服务器
  ExecutorService exec = Executors.newCachedThreadPool();
  UDPServer server = new UDPServer();
  exec.execute(server);

  // 发送消息
  send_bt.setOnClickListener(new OnClickListener() {
   @Override
   public void onClick(View v) {
    UDPClient client = new UDPClient(msg_et.getText().toString());
    info_tv.setText(client.send());
   }
  });
 }
}