I recently wrote a high quality, low grade, server side WebSocket (RFC 6455) implementation. The intended use-case is as follows:
- I want to create a service in Java that accepts connections from modern web browsers.
- I want to use InputStream and OutputStream to get my bytes back and forth between my service and the browser.
- I want my service code to do this with minimal setup.
- I want to ignore all the protocol details; just give me the bytes.
- I'm not sure, but I might like to support SSL/TLS security (i.e.: HTTPS) for none/some/all of my connections.
Need More?
If you need something else, like Java NIO support, non-blocking I/O, evented I/O, ability to provide custom handlers for web frames, etc.. then you'll probably need to find another implementation:
- http://stackoverflow.com/questions/4003102/best-java-framework-for-server-side-websockets
- http://stackoverflow.com/questions/4278456/websockets-production-ready-server-in-java
- http://stackoverflow.com/questions/4292624/java-websocket-host
Just Enough
Since you're still reading this, I'll assume you want to know more about my WebSocket implementation. You can find the repository here:
https://github.com/blinkdog/websocket
How does it work? I'm glad you asked...
This is how you start listening for WebSocket connections:
ServerSocket serverSocket = new ServerSocket(PORT);
WebSocketServerSocket webSocketServerSocket = new WebSocketServerSocket(serverSocket);
WebSocket webSocket = webSocketServerSocket.accept();
And this is how you read data from the connecting client:
InputStream is = webSocket.getInputStream();
int data = is.read();
And this is how you communicate back to the connecting client:
WebSocketServerOutputStream os = webSocket.getOutputStream();
os.writeString("This is a UTF-8 string.");
os.writeBinary("Some binary data.".getBytes()); 