netty websocket

1 全局保存websocket的通道 NettyConfig.java

public class NettyConfig {
    public static ChannelGroup group = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
}

2 WebsocketHandler.java 接收处理响应客户端发来的消息

/**
 * 接收处理响应客户端处理 *
 */
public class WebsocketHandler extends SimpleChannelInboundHandler<Object>{
    private WebSocketServerHandshaker handshaker;
    private static final String WEB_SOCKET_URL = "ws://192.168.3.167:8888/websocket";
    //客户端与服务端创建连接的时候调用
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        NettyConfig.group.add(ctx.channel());
        System.out.println("客户端与服务端连接开启...");
    }

    //客户端与服务端断开连接的时候调用
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        NettyConfig.group.remove(ctx.channel());
        System.out.println("客户端与服务端连接关闭...");
    }

    //服务端接收客户端发送过来的数据结束之后调用
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
            ctx.flush();
    }

    //工程出现异常的时候调用
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }

    //服务端处理客户端websocket请求的核心方法
    @Override
    protected void messageReceived(ChannelHandlerContext context, Object msg) throws Exception {
        //处理客户端向服务端发起http握手请求的业务
        if (msg instanceof FullHttpRequest) {
            handHttpRequest(context,  (FullHttpRequest)msg);
        }else if (msg instanceof WebSocketFrame) { //处理websocket连接业务
            handWebsocketFrame(context, (WebSocketFrame)msg);
        }
    }
    
    /**
     * 处理客户端与服务端之前的websocket业务
     * @param ctx
     * @param frame
     */
    private void handWebsocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame){
        //判断是否是关闭websocket的指令
        if (frame instanceof CloseWebSocketFrame) {
            handshaker.close(ctx.channel(), (CloseWebSocketFrame)frame.retain());
        }
        //判断是否是ping消息
        if (frame instanceof PingWebSocketFrame) {
            ctx.channel().write(new PongWebSocketFrame(frame.content().retain()));
            return;
        }
        
        //判断是否是二进制消息，如果是二进制消息，抛出异常
        if( ! (frame instanceof TextWebSocketFrame) ){
            System.out.println("目前我们不支持二进制消息");
            throw new RuntimeException("【"+this.getClass().getName()+"】不支持消息");
        }
        //返回应答消息
        //获取客户端向服务端发送的消息
        String request = ((TextWebSocketFrame) frame).text();
        System.out.println("服务端收到客户端的消息====>>>" + request);
        TextWebSocketFrame tws = new TextWebSocketFrame(new Date().toString() 
                                                                                        + request);
        //群发，服务端向每个连接上来的客户端群发消息
        //NettyConfig.group.writeAndFlush(tws);
        
        //单发  发给莫个人
        NettyConfig.group.find(ctx.channel().id()).writeAndFlush(tws);
            
        
    }
    /**
     * 处理客户端向服务端发起http握手请求的业务
     * @param ctx
     * @param req
     */
    private void handHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req){
        if (!req.getDecoderResult().isSuccess() 
                || ! ("websocket".equals(req.headers().get("Upgrade")))) {
            sendHttpResponse(ctx, req, 
                    new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));
            return;
        }
        WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(
                WEB_SOCKET_URL, null, false);
        handshaker = wsFactory.newHandshaker(req);
        if (handshaker == null) {
            WebSocketServerHandshakerFactory.sendUnsupportedWebSocketVersionResponse(ctx.channel());
        }else{
            handshaker.handshake(ctx.channel(), req);
        }
    }
    
    /**
     * 服务端向客户端响应消息
     * @param ctx
     * @param req
     * @param res
     */
    private void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req,
            DefaultFullHttpResponse res){
        if (res.getStatus().code() != 200) {
            ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(), CharsetUtil.UTF_8);
            res.content().writeBytes(buf);
            buf.release();
        }
        //服务端向客户端发送数据
        ChannelFuture f = ctx.channel().writeAndFlush(res);
        if (res.getStatus().code() != 200) {
            f.addListener(ChannelFutureListener.CLOSE);
        }
    }
    
}

3 初始化连接时候的各个组件

**
 * 初始化连接时候的各个组件 *
 */
public class MyWebSocketChannelHandler extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel e) throws Exception {
        e.pipeline().addLast("http-codec", new HttpServerCodec());
        e.pipeline().addLast("aggregator", new HttpObjectAggregator(65536));
        e.pipeline().addLast("http-chunked", new ChunkedWriteHandler());
        e.pipeline().addLast("handler", new WebsocketHandler());
    }

}

4 启动服务

/**
 * 程序的入口，负责启动应用
 *
 */
public class Main {
    public static void main(String[] args) {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workGroup);
            b.channel(NioServerSocketChannel.class);
            b.childHandler(new MyWebSocketChannelHandler());
            System.err.println("服务端开启等待客户端连接....");
            Channel ch = b.bind(8888).sync().channel();
            ch.closeFuture().sync();
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            //优雅的退出程序
            bossGroup.shutdownGracefully();
            workGroup.shutdownGracefully();
        }
    }
}

5 客户端连接服务

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset = utf-8"/>
        <title>WebSocket客户端</title>
    <script type="text/javascript">
        var socket;
        if(!window.WebSocket){
            window.WebSocket = window.MozWebSocket;
        }

        if(window.WebSocket){
            socket = new WebSocket("ws://localhost:8888/websocket");
            socket.onmessage = function(event){
                var ta = document.getElementById('responseContent');
                ta.value += event.data + "\r\n";
            };

            socket.onopen = function(event){
                var ta = document.getElementById('responseContent');
                ta.value = "你当前的浏览器支持WebSocket,请进行后续操作\r\n";
            };

            socket.onclose = function(event){
                var ta = document.getElementById('responseContent');
                ta.value = "";
                ta.value = "WebSocket连接已经关闭\r\n";
            };
        }else{
            alert("您的浏览器不支持WebSocket");
        }


        function send(message){
            if(!window.WebSocket){
                return;
            }
            if(socket.readyState == WebSocket.OPEN){
                socket.send(message);
            }else{
                alert("WebSocket连接没有建立成功！！");
            }
        }
    </script>
    </head>
    <body>
        <form onSubmit="return false;">
            <input type = "text" name = "message" value = ""/>
            <br/><br/>
            <input type = "button" value = "发送WebSocket请求消息" onClick = "send(this.form.message.value)"/>
            <hr color="red"/>
            <h2>客户端接收到服务端返回的应答消息</h2>
            <textarea id = "responseContent" style = "width:1024px; height:300px"></textarea>
        </form>
    </body>
</html>

6 也可以用java连接websocket服务

/**
 * java websocket客户端
 *
 */
public class WebSocketClientTest {
      
    public static WebSocketClient client;  
    public static void main(String[] args) {  
        try {  
            client = new WebSocketClient(new URI("ws://192.168.3.167:8888/websocket"),new Draft_6455()) {  
                @Override  
                public void onOpen(ServerHandshake serverHandshake) {  
                     System.err.println("握手成功");  
                }  
                @Override  
                public void onMessage(String msg) {  
                     System.err.println("收到消息=========="+msg);  
                     if(msg.equals("over")){  
                         client.close();  
                     }  
                       
                }  
  
                @Override  
                public void onClose(int i, String s, boolean b) {  
                     System.err.println("链接已关闭");  
                }  
  
                @Override  
                public void onError(Exception e){  
                    e.printStackTrace();  
                    System.err.println("发生错误已关闭");  
                }  
            };  
        } catch (URISyntaxException e) {  
            e.printStackTrace();  
        }  
        client.connect();  
        System.err.println(client.getDraft());  
       while(!client.getReadyState().equals(WebSocket.READYSTATE.OPEN)){  
           System.err.println("正在连接...");  
        }  
       //连接成功,发送信息  
    client.send("哈喽,连接一下啊");  
         
    }  
}

7 netty 和websocketclient依赖

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<dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>5.0.0.Alpha1</version>
        </dependency>
        <dependency>  
            <groupId>org.java-websocket</groupId>  
            <artifactId>Java-WebSocket</artifactId>  
            <version>1.3.5</version>  
        </dependency>

8 感谢慕课网相关资源

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