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POProblem sending data over UDP sockets
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  1. POProblem sending data over UDP sockets
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    copied!<p>This is kind of a followup to the question I had yesterday. I had a homework assignment to send and receive data with a client/server TCP socket connection. I would like to make a version of it using UDP. The idea is that I can redirect standard I/O and send the streams using UDP. For example, if I type in:</p> <pre><code> server: java UDPServer 5555 &lt; file1.txt client: java UDPClient localhost 5555 &gt; file2.txt </code></pre> <p>It should send the data in file1.txt from the server to client's file2.txt. When I run the client/server pair in separate terminals, file2.txt is created but the data is never actually sent. Instead it seems like I am stuck in an infinite loop, where I cannot enter anything into the terminal unless I kill the application. </p> <p>The server code is:</p> <pre><code>public static final int BUF_SIZE = 256; public static void main(String[] args) throws IOException{ port = Integer.parseInt(args[0]); DatagramSocket serverSocket = new DatagramSocket(port); BufferedInputStream input = new BufferedInputStream(System.in); BufferedOutputStream output = new BufferedOutputStream(System.out); byte[] receiveData = new byte[BUF_SIZE]; byte[] sendData = new byte[BUF_SIZE]; byte[] buf = new byte[BUF_SIZE]; String sentence; if(System.in.available() &gt; 0) { DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length); serverSocket.receive(receivePacket); InetAddress address = receivePacket.getAddress(); int bytesRead = 0; while((bytesRead = input.read(buf, 0, BUF_SIZE)) != -1) { sentence = new String(buf, 0, bytesRead); sendData = sentence.getBytes(); DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, address, port); serverSocket.send(sendPacket); } } else { DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length); serverSocket.receive(receivePacket); sentence = new String(receivePacket.getData()); output.write(sentence.getBytes()); } serverSocket.close(); input.close(); output.close(); } </code></pre> <p>And the client code is:</p> <pre><code>public static final int BUF_SIZE = 256; public static void main(String[] args) throws IOException{ String hostName = args[0]; port = Integer.parseInt(args[1]); DatagramSocket clientSocket = new DatagramSocket(); InetAddress address = InetAddress.getByName(hostName); BufferedInputStream input = new BufferedInputStream(System.in); BufferedOutputStream output = new BufferedOutputStream(System.out); byte[] sendData = new byte[BUF_SIZE]; byte[] receiveData = new byte[BUF_SIZE]; byte[] buf = new byte[BUF_SIZE]; String sentence; if(System.in.available() &gt; 0) { int bytesRead = 0; while((bytesRead = input.read(buf, 0, BUF_SIZE)) != -1) { sentence = new String(buf, 0, bytesRead); sendData = sentence.getBytes(); DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, address, port); clientSocket.send(sendPacket); } } else { DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length); clientSocket.receive(receivePacket); sentence = new String(receivePacket.getData()); output.write(sentence.getBytes()); } clientSocket.close(); input.close(); output.close(); } </code></pre> <p>I am still new to socket programming so I am basing this off of example code in my textbook. Is there some glaring mistake that I am making that is preventing the data from being transferred? Thanks very much for your patience and help!</p>
 

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