Netty Websocket

服务端代码：

TestServer.java

package com.dongqiang.netty.fifthexample;

import com.dongqiang.netty.fourthexample.MyServerInitializer;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;

/**
 * Netty对websocket的支持
 */
public class TestServer {
    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)).childHandler(new TestServerInitializer());
            ChannelFuture channelFuture = serverBootstrap.bind("localhost", 8899).sync();
            channelFuture.channel().closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

TestServerInitializer.java

package com.dongqiang.netty.fifthexample;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.stream.ChunkedWriteHandler;

/**
 * Created by dongqiang on 2017/6/11.
 */
public class TestServerInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        pipeline.addLast(new HttpServerCodec());
        pipeline.addLast(new ChunkedWriteHandler());//以块的方式写
        pipeline.addLast(new HttpObjectAggregator(8192));
        pipeline.addLast(new WebSocketServerProtocolHandler("/ws"));//context_path

        pipeline.addLast(new TextWebSocketFrameHandler());
    }
}

TextWebSocketFrameHandler.java

package com.dongqiang.netty.fifthexample;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;

import java.time.LocalDateTime;

/**
 * Created by dongqiang on 2017/6/11.
 */
public class TextWebSocketFrameHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {
        System.out.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 {
        System.out.println("handlerAdded: " + ctx.channel().id().asLongText());
    }

    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        System.out.println("handlerRemoved：" + ctx.channel().id().asLongText());
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        System.out.println("异常发生");
        ctx.close();
    }
}

ws://server:port/context_path

ws://localhost:9999/ws, /ws是context_path。

客户端使用Chrome浏览器：

test.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>WebSocket客户端</title>
</head>
<body>
    <script>
        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("连接尚未开始！");
            }
        }

    </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>服务器输出：</h3>
        <textarea id="responseText" style="width: 400px; height: 300px"></textarea>
        <input type="button" onclick="javascript: document.getElementById('responseText').value=''" value="清空内容">
    </form>

</body>
</html>