Java 客户端未收到 C# 服务器响应 TCP

Question

有人可以向我解释我做错了什么。我第一次尝试在 Java 和 C# 之间实施 TCP：

服务器代码 c# `

public void CreateServer()
        {
            Thread thread = new Thread(() =>
            {
                IPAddress addr = IPAddress.Parse(localIP);
                tcpListener = new TcpListener(addr, 5053);
                if (tcpListener != null)
                {
                    tcpListener.Start();
                    while (!end)
                    {      
                        TcpClient tcpClient = tcpListener.AcceptTcpClient();
                        var ip = ((IPEndPoint)tcpClient.Client.RemoteEndPoint).Address.ToString();
                        Console.WriteLine("Client connected from "+ip);   
                        NetworkStream clientStream = tcpClient.GetStream();
                        StreamReader reader = new StreamReader(clientStream, Encoding.UTF8);
                        try
                        {
                            string request = reader.ReadToEnd();
                            Console.WriteLine("Message from client: " + request);

                            Byte[] StringToSend = Encoding.UTF8.GetBytes("Server");
                            clientStream.Write(StringToSend, 0, StringToSend.Length);
                            Console.WriteLine("Sending response back");
                        }
                        catch (Exception e)
                        {
                            Console.WriteLine(e);
                        } 
                    }
                }
            });
            thread.Start();
        }

`

客户代码 java `

public class TCP {

    private String IP;
    private InetAddress server;
    private Socket socket;

    public TCP(String IP) {
        this.IP = IP;
    }

    protected void runTCP() {
        try {
            server = InetAddress.getByName(IP);
            socket = new Socket(server, 5053);
            System.out.println("Client connected. Listening on port 5053");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void sendMessage(String message) {
        try {
            System.out.println("Sending data...");
            if (socket.isClosed()) socket = new Socket(server, 5053);
            PrintWriter writer = new PrintWriter(socket.getOutputStream());
            writer.print(message);
            writer.flush();
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void getResponseServer() {
        Thread thread = new Thread() {
            @Override
            public void run() {
                try {
                    System.out.println("Attempting to get response...");
                    if (socket.isClosed()) socket = new Socket(server, 5053);
                    BufferedReader mBufferIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                    String mServerMessage = mBufferIn.readLine();
                    System.out.println("Server message: " + mServerMessage);
                } catch (Exception e) {e.printStackTrace();}
            }
        };
        thread.start();
    }
}

`

服务器上的 Output 当从客户端向服务器发送“你好”时我得到： Client connected from 192.16.... Message from client: Hello Sending response back Client connected from 192.16....

客户端上的 Output： Client connected. Listening on port 5053 Sending data... Attempting to get response... Client connected. Listening on port 5053 Sending data... Attempting to get response...从未得到响应...为什么？

尝试研究但一无所获，尝试了其他代码但也没有用......

Answer 1

对不起，我不能发表评论。 也许您可以使用te.net命令来验证 c# 代码是否正确。

telnet ip port

先定位问题，再解决问题。

如果服务器没问题，我们可以使用nc命令验证客户端代码，我测试了你的java代码，除了每次发送数据都会关闭套接字，其他都可以。

Answer 2

通过删除导致套接字关闭的 writer.close() 原因修复它，并通过再次创建使服务器等待 stream 数据并且客户端等待响应的套接字与服务器建立另一个连接...

        System.out.println("Sending data...");
        PrintWriter writer = new PrintWriter(socket.getOutputStream(), true);
        writer.println(message);

        InputStream input = socket.getInputStream();
        BufferedReader reader = new BufferedReader(new InputStreamReader(input));
        String line;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }