我正在尝试为Java中的类赋值实现可靠的UDP协议。我已设法将确认添加到收到的每个数据报包中，但我在发送的数据报包中无法实现序列号。
有人能建议一种简单的方法来实现这个吗？
@EJP我尝试过你刚刚建议的内容。这是我的代码，直到现在（它仍然非常原始 - 我正在使用命中和尝试方法来实现它）
服务器端
public class TestServer extends Activity {
private DatagramSocket serverSocket;
Thread serverThread = null;
byte[] incomingData;
byte[] outgoingData;
//int numBytesRead = 0;
int ackSent = 0;
int numPackRecv = 0;
int BUF_SIZE = 1024;
String msg = "ACK";
BufferedInputStream data=null;
BufferedOutputStream out =null;
public static final int SERVERPORT = 6000;
String outputFile = "/sdcard/Movies/asddcopy.mp4";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test_server);
this.serverThread = new Thread(new ServerThread());
this.serverThread.start();
}
@Override
protected void onStop() {
super.onStop();
try {
serverSocket.close();
} catch (Exception e) {
Log.d("SERVER", "Inside onStop()");
Log.d("SERVER", Log.getStackTraceString(e));
}
}
class ServerThread implements Runnable {
@SuppressLint("NewApi")
public void run() {
try {
serverSocket = new DatagramSocket(SERVERPORT);
incomingData = new byte[BUF_SIZE];
//outgoingData = new byte[512];
outgoingData = msg.getBytes();
long startRxPackets = TrafficStats.getUidRxPackets(Process.myUid());
long startTime = System.nanoTime();
out = new BufferedOutputStream(new FileOutputStream(outputFile, true));
while (!Thread.currentThread().isInterrupted()) {
//serverSocket.setSoTimeout(5000);
while (true) {
try{
//DatagramPacket incomingPacket = new DatagramPacket(incomingData, incomingData.length);
DatagramPacket incomingPacket = new DatagramPacket(incomingData, BUF_SIZE);
serverSocket.receive(incomingPacket);
byte[] data = incomingPacket.getData();
//out.write(data,0,incomingPacket.getLength());
//String msg = new String(incomingPacket.getData());
ByteArrayInputStream in = new ByteArrayInputStream(data);
ObjectInputStream is = new ObjectInputStream(in);
if (is == null) {
is = new ObjectInputStream(in);
}
Message msg = (Message) is.readObject();
System.out.println(msg.getSeqNo());
/*if ("END".equals(msg.substring(0, 3).trim())) {
Log.d("SERVER", "Inside END condition");
break;
}*/
out.write(msg.getData(),0,msg.getData().length);
numPackRecv += 1;
Log.d("SERVER", "Packet Received: " + numPackRecv);
InetAddress client = incomingPacket.getAddress();
int client_port = incomingPacket.getPort();
DatagramPacket outgoingPacket = new DatagramPacket(outgoingData, outgoingData.length, client, client_port);
serverSocket.send(outgoingPacket);
ackSent += 1;
//Log.d("SERVER","Packet Received: " + numPackRecv + " :: " + "Ack Sent: " + ackSent);
}catch(Exception e) {
Log.d("SERVER", "Inside run() ex1");
Log.d("SERVER", Log.getStackTraceString(e));
break;
}
}
out.close();
serverSocket.disconnect();
serverSocket.close();
Log.d("SERVER", "Transfer Complete");
Log.d("SERVER", "Actual Time elapsed = " + (System.nanoTime() - startTime)/Math.pow(10, 9) + " s");
Log.d("SERVER", "Total Packets Received = " + Long.toString(TrafficStats.getUidRxPackets(Process.myUid()) - startRxPackets));
Log.d("SERVER", "Packets Received from Socket = " + numPackRecv);
break;
}
out.close();
serverSocket.disconnect();
serverSocket.close();
/* Log.d("SERVER", "Transfer Complete");
Log.d("SERVER", "Actual Time elapsed = " + (System.nanoTime() - startTime)/Math.pow(10, 9) + " s");
Log.d("SERVER", "Total Packets Received = " + Long.toString(TrafficStats.getUidRxPackets(Process.myUid()) - startRxPackets));
Log.d("SERVER", "Packets Received from Socket = " + numPackRecv);*/
}catch (Exception e) {
Log.d("SERVER", "Inside run() ex2");
Log.d("SERVER", Log.getStackTraceString(e));
serverSocket.disconnect();
serverSocket.close();
}
}
}
这是客户端
public class TestClient extends Activity { private DatagramSocket clientSocket;
byte[] incomingData;
int BUF_SIZE = 500;
int numBytesRead = 0;
int numPackSent = 0;
private static final int SERVERPORT = 6000;
private static final String SERVER_IP = "10.0.0.22";
String inFile = "/sdcard/Movies/asdd.mp4";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test_client);
new Thread(new ClientThread()).start();
}
public void onClick(View view) {
new workInProgress().execute("");
}
private class workInProgress extends AsyncTask<Object, Object, Object> {
@SuppressLint("NewApi")
@Override
protected Object doInBackground(Object... params) {
try {
Log.d("CLIENT", "Sending a file to the server...");
BufferedInputStream inputBuf = new BufferedInputStream(new FileInputStream(inFile));
//byte[] fileBytes = new byte[(int) inFile.length()];
byte[] fileBytes = new byte[BUF_SIZE];
incomingData = new byte[BUF_SIZE];
double numPktToSend = Math.ceil(inFile.length()*1.0/BUF_SIZE);
//Log.d("CLIENT", "Total packets to be sent = " + numPktToSend);
int sleepCycle = 1;
long sysPackSent = 0;
//long startTxPackets = TrafficStats.getTotalTxPackets();
long startTxPackets = TrafficStats.getUidTxPackets(Process.myUid());
Log.d("CLIENT", "startTxPacks: " + startTxPackets);
long packDrops = 0;
long startTime = System.nanoTime();
long count=0;
long ackRec=0;
int seqNo = 0;
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
ObjectOutputStream os = new ObjectOutputStream(outStream);
while((numBytesRead = inputBuf.read(fileBytes)) != -1) {
//DatagramPacket packet = new DatagramPacket(fileBytes, fileBytes.length);
if (os == null) {
os = new ObjectOutputStream(outStream);
}
Message msg = new Message(++seqNo, fileBytes, false);
os.writeObject(msg);
os.flush();
os.reset();
byte[] data = outStream.toByteArray();
DatagramPacket packet = new DatagramPacket(data, data.length);
clientSocket.send(packet);
numPackSent += 1;
//Log.d("CLIENT", "No of packets sent = " + numPackSent);
sysPackSent = TrafficStats.getUidTxPackets(Process.myUid()) - startTxPackets;
try{
clientSocket.setSoTimeout(5000);
packet = new DatagramPacket(incomingData, incomingData.length);
clientSocket.receive(packet);
String recAck = new String(packet.getData());
ackRec++;
}
catch(Exception e) {
//Log.d("CLIENT", Log.getStackTraceString(e));
}
packDrops = numPackSent - ackRec;
if (packDrops > count) {
sleepCycle = Math.min(16, sleepCycle * 2);
count = packDrops;
Log.d("CLIENT",String.valueOf(sleepCycle) + " :: " + numPackSent);
} else {
sleepCycle = Math.max(sleepCycle - 1, 1);
}
Thread.sleep(sleepCycle);
}
if (numBytesRead == -1) {
fileBytes = "END".getBytes();
Log.d("CLIENT", "Sending END Packet");
clientSocket.send(new DatagramPacket(fileBytes, fileBytes.length));
}
Log.d("CLIENT", "Actual Time elapsed = " + (System.nanoTime() - startTime)/Math.pow(10, 9) + " s");
Log.d("CLIENT", "Total Packets Transmitted = " + Long.toString(sysPackSent));
Log.d("CLIENT", "No of packets dropped = " + String.valueOf(packDrops));
Log.d("CLIENT", "Packets Pushed to Socket = " + numPackSent);
Log.d("CLIENT", "Number of Acknoledgments received " +ackRec);
inputBuf.close();
os.close();
outStream.close();
clientSocket.disconnect();
clientSocket.close();
Log.d("CLIENT", "Sending file.. Complete!!!");
} catch (Exception e) {
Log.d("CLIENT", Log.getStackTraceString(e));
clientSocket.disconnect();
clientSocket.close();
}
return null;
}
}
class ClientThread implements Runnable {
@Override
public void run() {
try {
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
clientSocket = new DatagramSocket();
clientSocket.connect(serverAddr, SERVERPORT);
Log.d("CLIENT", "Connection Successful");
} catch (UnknownHostException e1) {
Log.d("CLIENT", "Inside run() UnknownHostEx");
Log.d("CLIENT", Log.getStackTraceString(e1));
} catch (IOException e1) {
Log.d("CLIENT", "Inside run() IOEx");
Log.d("CLIENT", Log.getStackTraceString(e1));
}
}
}
我在服务器端遇到一些错误：
如果你能提出更好的方法来实现同样的事情，我真的很感激！ 谢谢:)）
谢谢！
答案 0 :(得分：2)
ByteArrayOutputStream. DataOutputStream DataOutputStream.writeInt()编写序列号。write()写入数据。DatagramPacket ByteArrayOutputStream.
在接收器处，完全相反，在每种情况下使用补充类和方法。这些是留给读者的练习。
答案 1 :(得分：1)
最简单的方法可能是查看TCP协议，并将所有TCP标头粘贴到每个UDP数据包的开头。