我目前正在编写一个程序，通过TCP数据包与托管在单独设备上的服务器进行通信。写入服务器工作正常，但我似乎永远无法读取响应。我很肯定有一个回应，因为在嗅探网络数据包时，我看到来自设备的传入数据包，尽管程序从未检测到它。
public class SocketTest
{
private Socket socket;
private int currentSequence = 0;
public static void main(String[] args)
{
new SocketTest();
}
public SocketTest()
{
try
{
System.out.println("Connecting");
socket = new Socket("192.168.1.8", 8000);
System.out.println("Connected!");
System.out.println("Pinging...");
sendPacket(0, 3, null, 0);
System.out.println("Pinged!");
System.out.println("Reading..");
while (socket.isConnected())
{
byte[] res = new byte[84];
socket.getInputStream().read(res);
System.out.println("Read!");
}
}
catch (IOException e)
{
e.printStackTrace();
}
}
public void sendPacket(int type, int command, int[] args, int length)
{
int t = 0;
currentSequence += 1000;
byte[] resultBuffer = new byte[84];
byte[] payload1 = getBytes(0x12345678);
System.arraycopy(payload1, 0, resultBuffer, t, payload1.length);
t += 4;
byte[] payload2 = getBytes(currentSequence);
System.arraycopy(payload2, 0, resultBuffer, t, payload2.length);
t += 4;
byte[] payload3 = getBytes(type);
System.arraycopy(payload3, 0, resultBuffer, t, payload3.length);
t += 4;
byte[] payload4 = getBytes(command);
System.arraycopy(payload4, 0, resultBuffer, t, payload4.length);
for (int i = 0; i < 16; i++)
{
t += 4;
int arg = 0;
if (args != null)
{
arg = args[i];
}
byte[] payloadArg = getBytes(arg);
System.arraycopy(payloadArg, 0, resultBuffer, t, payloadArg.length);
}
t += 4;
byte[] payload5 = getBytes(length);
System.arraycopy(payload5, 0, resultBuffer, t, payload5.length);
write(resultBuffer, 0, resultBuffer.length);
}
private void write(byte[] buffer, int startOffset, int length)
{
DataOutputStream out;
try
{
out = new DataOutputStream(socket.getOutputStream());
out.write(buffer, startOffset, length);
out.flush();
}
catch (IOException e)
{
e.printStackTrace();
}
}
private byte[] getBytes(int value)
{
ByteBuffer buffer = ByteBuffer.allocate(4).order(ByteOrder.nativeOrder());
buffer.putInt(value);
return buffer.array();
}
}
我尝试了一堆不同的阅读方法..多线程，心跳等。但每次我使用InputStream的read（）方法时，它都会阻塞，因为没有数据要读取，而套接字肯定是打开的因为结果不是-1。
这是我在我的程序中使用的实际读取方法（上面的代码是缩短的xample）
private int read(byte[] buffer, int offset, int length)
{
int res = 0;
DataInputStream bis;
try
{
bis = new DataInputStream(socket.getInputStream());
if (bis.available() > 0)
{
System.out.println("Waiting bytes: " + bis.available());
System.out.println("buffer = [" + Arrays.toString(buffer) + "], offset = [" + offset + "], length = [" + length + "]");
res = bis.read(buffer, offset, length);
}
else
{
NTR.getLogger().debug("Available: " + bis.available());
}
}
catch (IOException e)
{
e.printStackTrace();
}
return res;
}
有趣的是，C＃版本的代码运行得很好。
namespace ntrclient
{
public class NtrClient
{
public delegate void LogHandler(string msg);
private readonly object _syncLock = new object();
private uint _currentSeq;
private int _heartbeatSendable;
public string Host;
private string _lastReadMemFileName;
private uint _lastReadMemSeq;
public NetworkStream NetStream;
public Thread PacketRecvThread;
public int Port;
public volatile int progress = -1;
public TcpClient Tcp;
public event LogHandler OnLogArrival;
private int ReadNetworkStream(Stream stream, byte [] buf, int length)
{
var index = 0;
var useProgress = length > 100000;
do
{
if (useProgress)
{
progress = (int) ((double) index / length * 100);
}
var len = stream.Read(buf, index, length - index);
if (len == 0)
{
Console.WriteLine("No data to be read");
return 0;
}
Console.WriteLine("Read " + len + " datas");
index += len;
} while (index < length);
progress = -1;
Console.WriteLine("Length: " + length + ", Buffer: " + buf);
return length;
}
private void PacketRecvThreadStart()
{
var buf = new byte [84];
var args = new uint [16];
var stream = NetStream;
while (true)
{
try
{
var ret = ReadNetworkStream(stream, buf, buf.Length);
if (ret == 0)
{
break;
}
var t = 0;
var magic = BitConverter.ToUInt32(buf, t);
t += 4;
var seq = BitConverter.ToUInt32(buf, t);
t += 4;
var type = BitConverter.ToUInt32(buf, t);
t += 4;
var cmd = BitConverter.ToUInt32(buf, t);
for (var i = 0; i < args.Length; i++)
{
t += 4;
args [i] = BitConverter.ToUInt32(buf, t);
}
t += 4;
var dataLen = BitConverter.ToUInt32(buf, t);
if (cmd != 0)
{
Log($"packet: cmd = {cmd}, dataLen = {dataLen}");
}
if (magic != 0x12345678)
{
Log($"broken protocol: magic = {magic}, seq = {seq}");
break;
}
if (cmd == 0)
{
if (dataLen != 0)
{
var dataBuf = new byte [dataLen];
ReadNetworkStream(stream, dataBuf, dataBuf.Length);
var logMsg = Encoding.UTF8.GetString(dataBuf);
Log(logMsg);
}
lock (_syncLock)
{
_heartbeatSendable = 1;
}
continue;
}
if (dataLen != 0)
{
var dataBuf = new byte [dataLen];
ReadNetworkStream(stream, dataBuf, dataBuf.Length);
HandlePacket(cmd, seq, dataBuf);
}
}
catch (Exception e)
{
Log(e.Message);
break;
}
}
Log("Server disconnected.");
Disconnect(false);
}
public void ConnectToServer()
{
if (Tcp != null)
{
Disconnect();
Log("Disconnected from previous server, connecting to new one");
}
new Thread(() =>
{
//Thread.CurrentThread.IsBackground = true;
Tcp = new TcpClient { NoDelay = true };
Tcp.Connect(Host, Port);
_currentSeq = 0;
NetStream = Tcp.GetStream();
_heartbeatSendable = 1;
PacketRecvThread = new Thread(PacketRecvThreadStart);
PacketRecvThread.Start();
Program.getMain().Connected = true;
Log("Server connected.");
}).Start();
}
public void Disconnect(bool waitPacketThread = true)
{
try
{
Tcp?.Close();
if (waitPacketThread)
{
PacketRecvThread?.Join();
}
// Not connected anymore
Program.getMain().Connected = false;
Log("Server disconnected.");
}
catch (Exception ex)
{
Log(ex.Message);
}
Tcp = null;
}
public void SendPacket(uint type, uint cmd, uint [] args, uint dataLen)
{
var t = 0;
_currentSeq += 1000;
var buf = new byte [84];
BitConverter.GetBytes(0x12345678).CopyTo(buf, t);
t += 4;
BitConverter.GetBytes(_currentSeq).CopyTo(buf, t);
t += 4;
BitConverter.GetBytes(type).CopyTo(buf, t);
t += 4;
BitConverter.GetBytes(cmd).CopyTo(buf, t);
for (var i = 0; i < 16; i++)
{
t += 4;
uint arg = 0;
if (args != null)
{
arg = args [i];
}
BitConverter.GetBytes(arg).CopyTo(buf, t);
}
t += 4;
BitConverter.GetBytes(dataLen).CopyTo(buf, t);
NetStream.Write(buf, 0, buf.Length);
}
public void SendHeartbeatPacket()
{
if (Tcp == null)
return;
lock (_syncLock)
{
if (_heartbeatSendable != 1)
return;
_heartbeatSendable = 0;
SendPacket(0, 0, null, 0);
}
}
}
}
老实说，我很难过。我注意到C＃的NetworkStream读写方法与java不同，但我不确切地知道它们有多么不同，或者它是否有所不同。
提前致谢！