Netty对WebSocket的支持

WebSocket长连接

一、创建服务端代码

1、MyServer 类

public class MyServer {

    public static void main(String[] args) throws  Exception{

        EventLoopGroup bossGroup = new NioEventLoopGroup();

        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try{

            ServerBootstrap serverBootstrap = new ServerBootstrap();

            serverBootstrap.group(bossGroup,workerGroup).channel(NioServerSocketChannel.class)

                    .handler(new LoggingHandler(LogLevel.INFO)) //增加日志处理器

                    .childHandler(new WebSocketChannelInitializer());

            ChannelFuture channelFuture = serverBootstrap.bind(new InetSocketAddress(8899)).sync();

            channelFuture.channel().closeFuture().sync();

        }finally {

            bossGroup.shutdownGracefully();

            workerGroup.shutdownGracefully();

        }

    }

}

2、WebSocketChannelInitializer 类

public class WebSocketChannelInitializer extends ChannelInitializer<SocketChannel>{

    protected void initChannel(SocketChannel socketChannel) throws Exception {

        ChannelPipeline pipeline = socketChannel.pipeline();

        pipeline.addLast(new HttpServerCodec());

        pipeline.addLast(new ChunkedWriteHandler());

        pipeline.addLast(new HttpObjectAggregator(8192));

        pipeline.addLast(new WebSocketServerProtocolHandler("/ws"));

        pipeline.addLast(new TextWebSocketFrameHandle());

    }

}

3、TextWebSocketFrameHandle 类

public class TextWebSocketFrameHandle extends SimpleChannelInboundHandler<TextWebSocketFrame> {

    @Override

    protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {

        CommonUtil.println("收到消息:" + msg.text());

        ctx.channel().writeAndFlush(new TextWebSocketFrame("服务器时间:" + LocalDateTime.now()));

    }

    @Override

    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {

        CommonUtil.println("handlerAdded:" +ctx.channel().id().asLongText());

    }

    @Override

    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {

        CommonUtil.println("handlerRemoved:" +ctx.channel().id().asLongText());

    }

    @Override

    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {

        CommonUtil.println("异常发生");

         ctx.close();

    }

}

二、编写客户端WebSocket代码

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>WebSocket</title>

</head>

<body>

<script type="text/javascript">

    var socket;

    if(window.WebSocket){

        socket = new WebSocket("ws://localhost:8899/ws");

        socket.onmessage = function (event) {

            var ta = document.getElementById("responseText");

            ta.value = ta.value + "\n" + event.data;

        }

        socket.onopen = function (event) {

            var ta = document.getElementById("responseText");

            ta.value = "连接开启";

        }

        socket.onclose = function (event) {

            var ta = document.getElementById("responseText");

            ta.value = ta.value + "\n" + "连接关闭！";

        }

    }else {

        alert("浏览器不支持WebSocket")

    }

    function  send(message) {

        if(!window.WebSocket){

            return;

        }

        if(socket.readyState == WebSocket.OPEN){

            socket.send(message);

        }else{

            alert("连接尚未开启");

        }

    }

</script>

<form onsubmit="return false">

    <textarea name="message" style="width: 400px ; height:  200px;" ></textarea>

    <input type="button" value="发送数据" onclick="send(this.form.message.value)">

    <h3>服务端输出:</h3>

    <textarea id="responseText" style="width: 400px ; height: 300px;" ></textarea>

    <input type="button" value="清空内容" onclick="javascript: document.getElementById('responseText').value=''">

</form>

</body>

</html>