Java：通过 TCP 发送/接收数据并从 UDP 接收图像
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【中文标题】Java：通过 TCP 发送/接收数据并从 UDP 接收图像【英文标题】：Java: send/receive data through TCP and receive image from UDP 【发布时间】：2021-12-14 01:22:12 【问题描述】：我正在编写来自 C# 的代码，并试图在 java 中引用它。 基本上在第一步中，我通过 TCP 向 IP 摄像机发送和接收一些数据命令（这已完成），在第二步中，我必须通过 UDP 接收图像。问题出在第二步：从 UDP 接收图像。 我尝试了互联网上的所有代码，但没有一个工作。
原来的C#代码是这样的：
*C#中的服务器连接示例
Socket _ServerUdp = null;
Socket _ServerTcpIp = null;
IPEndPoint _EndpointUdp = null;
TcpClient _ClientUdp;
/// <summary>
/// Connect the socket
/// <summary>
public bool Connect(string IpAddr)
if (!_VideoPortConnect(IpAddr, 8501))
return false;
if (!_CommandPortConnect(IpAddr, 8500))
return false;
return true;
/// <summary>
/// Udp Connect
/// </summary>
bool _VideoPortConnect(string IpAddr, int VideoPort)
try
_ServerUdp = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
_EndpointUdp = new IPEndPoint(IPAddress.Parse(IpAddr), VideoPort);
_ClientUdp = new TcpClient();
_ClientUdp.Connect(_EndpointUdp);
return true;
catch return false;
/// <summary>
/// Tcp Ip Connect
/// </summary>
bool _CommandPortConnect(string IpAddr, int CommandPort)
_ServerTcpIp = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint _RemoteEndPoint = new IPEndPoint(IPAddress.Parse(IpAddr), CommandPort);
_ServerTcpIp.ReceiveTimeout = 5000;
_ServerTcpIp.SendTimeout = 5000;
try
_ServerTcpIp.Connect(_RemoteEndPoint);
return true;
catch return false;
**
发送命令和接收图像示例 该命令将通过 TCP/IP 发送。
byte[] DataReceived = 新字节[20000];
/// <summary>
/// Send Command Bar Code Reader
/// </summary>
/// <returns></returns>
bool SendCommand()
byte[] _Send = new byte[3];
_Send[0]= 20; //CMD BAR CODE READER
_Send[1] = 2; //EXT CMD GET DATA
_Send[2] = 2; //SEND IMAGE
if (!SendEth(_Send, 3))
return false;
int _Ndati = ReadEth();
if (_Ndati == -1)
return false;
if (DataReceived[4] != 20)
return false;
GetImage();
/// <summary>
/// Send Data
/// </summary>
/// <param name="_Val"></param>
/// <param name="_Len"></param>
bool SendEth(byte[] _Val, Int32 _Len)
try
byte[] _Send = new byte[_Len + 4];
int _Value = _Len;
Array.Copy(_Val, 0, _Send, 4, _Len);
_Send[3] = (byte)_Value;
_Value <<= 8;
_Send[2] = (byte)_Value;
_Value <<= 8;
_Send[1] = (byte)_Value;
_Value <<= 8;
_Send[0] = (byte)_Value;
_ServerTcpIp.Send(_Send, _Len + 4, SocketFlags.None);
catch return false;
return true;
/// <summary>
/// Read Data from Ethernet
/// </summary>
/// <param name="LenDati"></param>
/// <returns>array dati</returns>
internal int ReadEth()
int _Ndati;
try
_Ndati = _ServerTcpIp.Receive(DataReceived, SocketFlags.None);
DataPointer =0;
int _Len = GetInt();
if(_Len!=_Ndati-4)
int _Diff = (_Ndati - 4) - _Len;
byte[] BuffRx = new byte[_Diff];
int _NrDati = 0;
int _PuntRx = _Ndati;
while (_PuntRx < _Diff)
_NrDati = _ServerTcpIp.Receive(BuffRx, _Diff, SocketFlags.None);
for (int n = 0; n < _NrDati; n++)
DataReceived[_PuntRx++] = BuffRx[n];
return _Ndati;
catch return -1;
/// <summary>
/// Get Image
/// </summary>
/// <returns></returns>
internal ImageSource GetImage()
//get image
NetworkStream _Stream = _ClientUdp.GetStream();
byte[] _Data = (byte[])_Formatter.Deserialize(_Stream);
MemoryStream _ImgStream = new MemoryStream(_Data);
ImageSource _Image = BitmapFrame.Create(_ImgStream, BitmapCreateOptions.None,
BitmapCacheOption.OnLoad);
return _Image;
我的 JAVA 代码：
公共类 TFinale
static byte[] DataReceived = new byte[20000];
public static void main(String[] args) throws Exception
String[] args8500 = new String[2];
args8500[0] = "10.0.0.123";
args8500[1] = "8500";
int port8500 = Integer.parseInt(args8500[1]);
String[] args8501 = new String[2];
args8501[0] = "10.0.0.123";
args8501[1] = "8501";
int port8501 = Integer.parseInt(args8501[1]);
Socket clientSocket8501 = TFinale.createSocket(args8501[0], port8501);
if (clientSocket8501 == null)
System.err.println("Unable to create socket to " + args8501[0] + ":" + port8501 + ".");
System.exit(1);
Socket clientSocket8500 = TFinale.createSocket(args8500[0], port8500);
if (clientSocket8500 == null)
System.err.println("Unable to create socket to " + args8500[0] + ":" + port8500 + ".");
System.exit(1);
byte[] _Send = new byte[3];
_Send[0] = 22; //CMD BAR CODE READER
_Send[1] = 2; //EXT CMD GET DATA
_Send[2] = 2; //SEND IMAGE
int _Len1 = 3;
byte[] SendEth1 = SendEth(_Send, _Len1);
DataOutputStream serverOut = null;
try
serverOut = new DataOutputStream(clientSocket8500.getOutputStream());
serverOut.write(SendEth1, 0, 7);
System.out.println("serverOut writed!");
catch (IOException ex)
Logger.getLogger(TFinale.class.getName()).log(Level.SEVERE, null, ex);
DataInputStream in = null;
try
byte[] messageByte = new byte[1000];
boolean end = false;
String dataString = "";
in = new DataInputStream(clientSocket8500.getInputStream());
int bytesRead = 0;
int f = 0;
//System.out.println("Please type 8500 clientSocket......");
for (f = 0; f < 7; f++)
messageByte[f] = in.readByte();
System.out.println("messageByte 8500[" + f + "] " + messageByte[f]);
ByteBuffer byteBuffer = ByteBuffer.wrap(messageByte, 0, f);
int bytesToRead = byteBuffer.getShort();
System.out.println("About to read " + bytesToRead + " octets");
catch (IOException ex)
Logger.getLogger(TCPClient1.class.getName()).log(Level.SEVERE, null, ex);
finally
try
in.close();
catch (IOException ex)
Logger.getLogger(TCPClient1.class.getName()).log(Level.SEVERE, null, ex);
timeDelay(1000);
try
serverOut.close();
System.out.println("serverOut closed!");
in.close();
System.out.println("in closed!");
clientSocket8501.close();
System.out.println("clientSocket8501 closed!");
clientSocket8500.close();
System.out.println("clientSocket8500 closed!");
catch (IOException ex)
System.out.println("error:" + ex);
private static Socket createSocket(final String hostname, final int port)
try
Socket clientSocket = new Socket(hostname, port);
System.out.println(hostname + ":" + port + " socket created!");
return clientSocket;
catch (UnknownHostException e)
System.err.println(" " + hostname + " cannot be resolved as a network host.");
return null;
catch (IOException e)
System.err
.println("An exception occurred while communicating with the TCPServer: "
+ e.getMessage());
e.printStackTrace();
return null;
private static void timeDelay(int i)
try
Thread.sleep(i);
catch (InterruptedException e)
private static byte[] SendEth(byte[] _Val, int _Len)
byte[] _Send = new byte[_Len + 4];
int _Value = _Len;
System.arraycopy(_Val, 0, _Send, 4, _Len);
//Array.Copy(_Val, 0, _Send, 4, _Len);
_Send[3] = (byte) _Value;
_Value <<= 8;
_Send[2] = (byte) _Value;
_Value <<= 8;
_Send[1] = (byte) _Value;
_Value <<= 8;
_Send[0] = (byte) _Value;
return _Send;
谢谢大家帮帮我！
【问题讨论】：
“它不起作用”对于任何人来说都没有足够的调试信息来提供帮助。发生什么了？这与您的预期有何不同？ FWIW，这似乎会混淆问题：TcpClient _ClientUdp; 所以我们有一个以 UDP 命名的对象，它显然是用于 TCP 的类型。我们使用的是 TCP 还是 UDP？我的猜测是 TCP，理由是使用 UDP 处理大数据似乎有点傻。
我在互联网上尝试了许多代码显示来监听地址：8501 中的 udp，但在发送命令期间没有收到任何内容...
【参考方案1】：
@Federico111，您应该使用java.net.DatagramSocket 而不是Socket 来使用UDP。
【讨论】：
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