Netty的websocket Demo

1.服務端

public final class WebSocketServer {

    static final boolean SSL = System.getProperty("ssl") != null;
    static final int PORT = Integer.parseInt(System.getProperty("port", SSL? "8443" : "8080"));

    public static void main(String[] args) throws Exception {
        // Configure SSL.
        final SslContext sslCtx;
        if (SSL) {
            SelfSignedCertificate ssc = new SelfSignedCertificate();
            sslCtx = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey()).build();
        } else {
            sslCtx = null;
        }

        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
             .channel(NioServerSocketChannel.class)
             .handler(new LoggingHandler(LogLevel.INFO))
             .childHandler(new WebSocketServerInitializer(sslCtx));

            Channel ch = b.bind(PORT).sync().channel();

            System.out.println("Open your web browser and navigate to " +
                    (SSL? "https" : "http") + "://127.0.0.1:" + PORT + '/');

            ch.closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

public class WebSocketServerInitializer extends ChannelInitializer<SocketChannel> {

    private static final String WEBSOCKET_PATH = "/websocket";

    private final SslContext sslCtx;

    public WebSocketServerInitializer(SslContext sslCtx) {
        this.sslCtx = sslCtx;
    }

    @Override
    public void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        if (sslCtx != null) {
            pipeline.addLast(sslCtx.newHandler(ch.alloc()));
        }
        pipeline.addLast(new HttpServerCodec());
        pipeline.addLast(new HttpObjectAggregator(65536));
        pipeline.addLast(new WebSocketServerProtocolHandler(WEBSOCKET_PATH, null, true));
        pipeline.addLast(new WebSocketFrameHandler());
    }
}

/**
 * Echoes uppercase content of text frames.
 */
public class WebSocketFrameHandler extends SimpleChannelInboundHandler<WebSocketFrame> {


    @Override
    protected void channelRead0(ChannelHandlerContext ctx, WebSocketFrame frame) throws Exception {
        // ping and pong frames already handled

        if (frame instanceof TextWebSocketFrame) {
            // Send the uppercase string back.
            String request = ((TextWebSocketFrame) frame).text();
            System.out.println(ctx.channel()+" received" + request);
            ctx.channel().writeAndFlush(new TextWebSocketFrame(request.toUpperCase(Locale.US)));
        } else {
            String message = "unsupported frame type: " + frame.getClass().getName();
            throw new UnsupportedOperationException(message);
        }
    }
}

服務端的pipeline中新增了WebSocketServerProtocolHandler，支援websocket，這是最重要的一步。

2.java客戶端

public final class WebSocketClient {

    static final String URL = System.getProperty("url", "ws://127.0.0.1:8080/websocket");

    public static void main(String[] args) throws Exception {
        URI uri = new URI(URL);
        String scheme = uri.getScheme() == null? "ws" : uri.getScheme();
        final String host = uri.getHost() == null? "127.0.0.1" : uri.getHost();
        final int port;
        if (uri.getPort() == -1) {
            if ("ws".equalsIgnoreCase(scheme)) {
                port = 80;
            } else if ("wss".equalsIgnoreCase(scheme)) {
                port = 443;
            } else {
                port = -1;
            }
        } else {
            port = uri.getPort();
        }

        if (!"ws".equalsIgnoreCase(scheme) && !"wss".equalsIgnoreCase(scheme)) {
            System.err.println("Only WS(S) is supported.");
            return;
        }

        final boolean ssl = "wss".equalsIgnoreCase(scheme);
        final SslContext sslCtx;
        if (ssl) {
            sslCtx = SslContextBuilder.forClient()
                .trustManager(InsecureTrustManagerFactory.INSTANCE).build();
        } else {
            sslCtx = null;
        }

        EventLoopGroup group = new NioEventLoopGroup();
        try {
            final WebSocketClientHandler handler =
                    new WebSocketClientHandler(
                            WebSocketClientHandshakerFactory.newHandshaker(
                                    uri, WebSocketVersion.V13, null, false, new DefaultHttpHeaders()));

            Bootstrap b = new Bootstrap();
            b.group(group)
             .channel(NioSocketChannel.class)
             .handler(new ChannelInitializer<SocketChannel>() {
                 @Override
                 protected void initChannel(SocketChannel ch) {
                     ChannelPipeline p = ch.pipeline();
                     if (sslCtx != null) {
                         p.addLast(sslCtx.newHandler(ch.alloc(), host, port));
                     }
                     p.addLast(
                             new HttpClientCodec(),
                             new HttpObjectAggregator(8192),
                             handler);
                 }
             });

            Channel ch = b.connect(uri.getHost(), port).sync().channel();
            handler.handshakeFuture().sync();

            BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
            while (true) {
                String msg = console.readLine();
                if (msg == null) {
                    break;
                } else if ("bye".equals(msg.toLowerCase())) {
                    ch.writeAndFlush(new CloseWebSocketFrame());
                    ch.closeFuture().sync();
                    break;
                } else if ("ping".equals(msg.toLowerCase())) {
                    WebSocketFrame frame = new PingWebSocketFrame(Unpooled.wrappedBuffer(new byte[] { 8, 1, 8, 1 }));
                    ch.writeAndFlush(frame);
                } else {
                    WebSocketFrame frame = new TextWebSocketFrame(msg);
                    ch.writeAndFlush(frame);
                }
            }
        } finally {
            group.shutdownGracefully();
        }
    }
}

public class WebSocketClientHandler extends SimpleChannelInboundHandler<Object> {

    private final WebSocketClientHandshaker handshaker;
    private ChannelPromise handshakeFuture;

    public WebSocketClientHandler(WebSocketClientHandshaker handshaker) {
        this.handshaker = handshaker;
    }

    public ChannelFuture handshakeFuture() {
        return handshakeFuture;
    }

    @Override
    public void handlerAdded(ChannelHandlerContext ctx) {
        handshakeFuture = ctx.newPromise();
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        handshaker.handshake(ctx.channel());
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) {
        System.out.println("WebSocket Client disconnected!");
    }

    @Override
    public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        Channel ch = ctx.channel();
        if (!handshaker.isHandshakeComplete()) {
            handshaker.finishHandshake(ch, (FullHttpResponse) msg);
            System.out.println("WebSocket Client connected!");
            handshakeFuture.setSuccess();
            return;
        }

        if (msg instanceof FullHttpResponse) {
            FullHttpResponse response = (FullHttpResponse) msg;
            throw new IllegalStateException(
                    "Unexpected FullHttpResponse (getStatus=" + response.getStatus() +
                            ", content=" + response.content().toString(CharsetUtil.UTF_8) + ')');
        }

        WebSocketFrame frame = (WebSocketFrame) msg;
        if (frame instanceof TextWebSocketFrame) {
            TextWebSocketFrame textFrame = (TextWebSocketFrame) frame;
            System.out.println("WebSocket Client received message: " + textFrame.text());
        } else if (frame instanceof PongWebSocketFrame) {
            System.out.println("WebSocket Client received pong");
        } else if (frame instanceof CloseWebSocketFrame) {
            System.out.println("WebSocket Client received closing");
            ch.close();
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        if (!handshakeFuture.isDone()) {
            handshakeFuture.setFailure(cause);
        }
        ctx.close();
    }
}

3.js客戶端

<!DOCTYPE html>  
<html>  
<head>  
  
<script type="text/javascript" charset="utf-8" >  
  window.WebSocket = window.WebSocket || window.MozWebSocket;  
    
 if (!window.WebSocket){  
     alert("WebSocket not supported by this browser");  
 }
    
var websocket = new WebSocket("ws://127.0.0.1:8080/websocket");  
 websocket.onmessage = function(evt){  
     var data = evt.data;  
      alert("received message: " + data);  
 }  
  
 function send() {  
 var name = document.getElementById('name').value;
    alert("websocket send message:"+name);  
    websocket.send(name);  
 }  
</script>  
</head>  
<body>  
<label for="name">What’s your name:</label>  
<input type="text" id="name" name="name" id='name'/>  
<button onclick="send()">Send</button>  
<div id="message" style="color:red"></div>  
</body>  
</html>