UDP是一个无连接协议，传输数据之前源端和终端不建立连接。对于udp来说并没有服务端和客户端，都是发送端和接收端。
android中使用DatagramSocket来创建udp的socket，使用DatagramPocket来存储数据。
1、创建DatagramSocket
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2、发送数据
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3、发送文件
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4、接收数据 这里的udpSocket.receive(DatagramPacket)阻塞方法，要在子线程中进行
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整体的代码
public class DealUdpService extends Service {
public DealUdpService() {
}
@Override
public IBinder onBind(Intent intent) {
return new MyBinder();
}
public class MyBinder extends Binder {
private DatagramSocket udpSocket;
private ExecutorService mExecutorService;//线程池
private String netIP = "192.168.2.223";//目标ip
private int netPort = 9000;//目标端口
private int heartTime = 5000;//间隔时间，接收和发送数据
private Handler uHandler = new Handler();
private int linkCount = 0;//连接次数
public void startUdp() {
if (mExecutorService == null) {
mExecutorService = Executors.newCachedThreadPool();
}
mExecutorService.execute(initSocket);
}
private Runnable initSocket = new Runnable() {
@Override
public void run() {
try {
// InetAddress address = InetAddress.getByName(netIP);
//这里必须要设置null，不然下面设置本地端口会报异常
udpSocket = new DatagramSocket(null);
udpSocket.setReuseAddress(true);
//设置本地端口
udpSocket.bind(new InetSocketAddress(9000));
//udpSocket.connect(address,netPort);
linkCount = 1;
uHandler.post(jieshou);
uHandler.post(fasong);
}catch (Exception e){
e.printStackTrace();
linkCount++;
Log.i("sun", "连接失败，进行第" + linkCount + "次重连");
uHandler.postDelayed(new Runnable() {
@Override
public void run() {
mExecutorService.execute(initSocket);
}
}, heartTime);
}
}
};
private Runnable fasong = new Runnable() {
@Override
public void run() {
sendData("123456789");
Log.i("sun", "发送数据");
}
};
//发送数据，可以暴露出去，在其他地方调用
private void sendData(String ss) {
mExecutorService.execute(new Runnable() {
@Override
public void run() {
try {
//uHandler.postDelayed(fasong,5000);定时发送
byte[] data = ss.getBytes();
DatagramPacket send = new DatagramPacket(data, data.length,new InetSocketAddress(netIP, netPort));
udpSocket.send(send);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* 发送文件
*/
private void sendFile(){
mExecutorService.execute(new Runnable() {
@Override
public void run() {
try {
InputStream in = getAssets().open("meet.docx");
int size = -1;
byte[] car = new byte[1024];
while ((size = in.read(car, 0, 1024)) != -1) {
//这里是发送文件，实际中应该是在对方回应后在发送下一包，添加说明数据
DatagramPacket send2 = new DatagramPacket(car, car.length,new InetSocketAddress(netIP, netPort));
udpSocket.send(send2);
}
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
private Runnable jieshou = new Runnable() {
@Override
public void run() {
Log.i("sun", "执行接收");
receiveData();
}
};
private void receiveData() {
mExecutorService.execute(new Runnable() {
@Override
public void run() {
try {
//uHandler.postDelayed(jieshou,5000);
byte[] result = new byte[1024];
while (true) {
DatagramPacket reveive = new DatagramPacket(result, result.length, new InetSocketAddress(netIP, netPort));
udpSocket.receive(reveive);
byte[] data = reveive.getData();
String ss = new String(data,0,reveive.getLength());
String cc = bytesToHex(data);
Log.i("sun", cc + "==接收到数据==" + ss);
}
} catch (Exception e) {
Log.i("sun","接收异常=="+e);
}
}
});
}
/**
* 将接收到byte数组转成String字符串
*
* @param bytes 接收的byte数组 16进制的数组
* @return string字符串
*/
private String bytesToHex(byte[] bytes) {
StringBuilder sb = new StringBuilder();
for (byte aByte : bytes) {
String hex = Integer.toHexString(aByte & 0xFF);
if (hex.length() < 2) {
sb.append(0);
}
sb.append(hex);
}
return sb.toString();
}
public void destory(){
uHandler.removeCallbacksAndMessages(null);
udpSocket.disconnect();
udpSocket.close();
}
}
}
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