Java的TCP和UDP回响在一台服务器(Java TCP and UDP echo in one

我试图建立它可以从一个TCP和UDP客户端呼应输入的服务器。

到目前为止，我可以拿出最好的是这样的：

import java.net.*;
import java.io.*;

public class EchoServerMultiProtocol {
    public static void main(String[] args) throws IOException {

        String clientSentence;
        String capitalizedSentence;

        while (true) {
            /*******************************************************************
             * * Handle TCP * *
             *******************************************************************/
            ServerSocket TCP_Socket = new ServerSocket(6789);

            Socket connectionSocket = TCP_Socket.accept();

            BufferedReader inFromClient = new BufferedReader(
                    new InputStreamReader(connectionSocket.getInputStream()));

            DataOutputStream outToClient = new DataOutputStream(
                    connectionSocket.getOutputStream());

            clientSentence = inFromClient.readLine();

            capitalizedSentence = clientSentence.toUpperCase() + '\n';

            outToClient.writeBytes(capitalizedSentence);

            /*******************************************************************
             * * Handle UDP * *
             *******************************************************************/
            DatagramSocket UDP_Socket = new DatagramSocket(9876);

            byte[] receiveData = new byte[1024];
            byte[] sendData = new byte[1024];

            DatagramPacket receivePacket = new DatagramPacket(receiveData,
                    receiveData.length);

            UDP_Socket.receive(receivePacket);

            clientSentence = new String(receivePacket.getData());

            InetAddress IPAddress = receivePacket.getAddress();

            int port = receivePacket.getPort();

            capitalizedSentence = clientSentence.toUpperCase();

            sendData = capitalizedSentence.getBytes();

            DatagramPacket sendPacket = new DatagramPacket(sendData,
                    sendData.length, IPAddress, port);

            UDP_Socket.send(sendPacket);

        }
    }
}

什么情况是，如果我从TCP客户端程序工作正常，但是从发送消息的UDP客户端没有任何反应。我不是在客户端/服务器通信十分精通所以任何帮助，将不胜感激。

客户端代码如下所示，但我怀疑他们是问题的根源。

TCP客户端

import java.io.*;
import java.net.*;

class EchoClientTCP {

    public static void main(String argv[]) throws Exception {
        String sentence;
        String modifiedSentence;

        BufferedReader inFromUser = new BufferedReader(new InputStreamReader(
                System.in));

        Socket clientSocket = new Socket("127.0.0.1", 6789);

        DataOutputStream outToServer = new DataOutputStream(
                clientSocket.getOutputStream());

        BufferedReader inFromServer = new BufferedReader(new InputStreamReader(
                clientSocket.getInputStream()));

        sentence = inFromUser.readLine();

        outToServer.writeBytes(sentence + '\n');

        modifiedSentence = inFromServer.readLine();

        System.out.println("FROM SERVER: " + modifiedSentence);

        clientSocket.close();

    }
}

UDP客户端

import java.io.*;
import java.net.*;

class EchoClientUDP {
    public static void main(String args[]) throws Exception {

        BufferedReader inFromUser = new BufferedReader(new InputStreamReader(
                System.in));

        DatagramSocket clientSocket = new DatagramSocket();

        InetAddress IPAddress = InetAddress.getByName("127.0.0.1");

        byte[] sendData = new byte[1024];
        byte[] receiveData = new byte[1024];

        String sentence = inFromUser.readLine();

        sendData = sentence.getBytes();

        DatagramPacket sendPacket = new DatagramPacket(sendData,
                sendData.length, IPAddress, 9876);

        clientSocket.send(sendPacket);

        DatagramPacket receivePacket = new DatagramPacket(receiveData,
                receiveData.length);

        clientSocket.receive(receivePacket);

        String modifiedSentence = new String(receivePacket.getData());

        System.out.println("FROM SERVER:" + modifiedSentence);

        clientSocket.close();

    }
}

谢谢您的帮助。

Answer 1:

你的程序块等待TCP消息，所以它永远不会看到任何UDP。

你需要，至少，两个线程，每个。

Answer 2:

接受是一个阻塞调用。它从来没有得到与UDP套接字代码的一部分。

Answer 3:

请你只让你的生活简单，使用了Netty 。在几行代码中你有一个高效的线程模型中，最常用的协议和一个伟大的框架来处理消息的支持。