CODEWITHSUNDEEP
javasocketsprocessing
InterestedDev
InterestedDev

Reputation: 11

Why can't my client (Processing) read from the ServerSocket (Java)?

I've written some code in Java and Processing because I'm interested how I can communicate between different programming languages.
In this case I want to write a "calculating" programm in Java and visualize it with Processing.

I have tried to set up servers from both directions, but I couldn't read anything from the servers :(

Java:

-------- Accepting clients --------
try {
  ServerSocket server = new ServerSocket(55000);

  System.out.println("Server started");

  while (true) {
    client = server.accept();
    handleConnection(client);
  }
} catch (IOException ex) { ... }


-------- handleConnection --------
System.out.println("Connection accepted");
try {
  PrintWriter os = new PrintWriter(client.getOutputStream());

  char[] buffer = "This is a wonderful sentence!".toCharArray();            

  for (char c : buffer)
    os.write(c);

  client.close();            
} catch (IOException ex) { ... }

Processing:

-------- Setup client --------
Client client = new Client(this, "127.0.0.1", 55000);

-------- Draw function (frame rate: 10) --------
try {    
  if (client.available() > 0)
    print(client.readChar());
  } catch (NullPointerException ex) {
    println("NullPointer");
  }

I've expected that the sentence would be written to the Processing console, but I get only the message "Client got end-of-stream.".

Upvotes: 1

Views: 57

Answers (2)

InterestedDev
InterestedDev

Reputation: 11

I've found the mistake; it's a PrintWriter / flushing problem because the PrintWriter does not autoflush the stream. "Manual" flushing / using the OutputStream directly solved the problem.

Upvotes: 0

ControlAltDel
ControlAltDel

Reputation: 35021

I looks like you are using a DataInputStream in client. You should only use this if you plan on sending/receiving serialized objects. I've done quite a bit of socket programming, and I've never wanted/needed to use DataInputStream... Try just using plain sockets - it's easier.

Upvotes: 1

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