30分鐘快速打造一個完善的直播聊天系統

├── WebSocketServer.java                啟動伺服器埠監聽
├── WebSocketServerInitializer.java     初始化服務
├── WebSocketServerHandler.java         接管WebSocket資料連線
├── dto
│   └── Response.java                   返回給客戶端資料物件
├── entity
│   └── Client.java                     每個連線到WebSocket服務的客戶端物件
└── service
    ├── MessageService.java             完成傳送訊息
    └── RequestService.java             WebSocket初始化連線握手時的資料處理

在 pom.xml 中引入netty 5

現在大家都有自己的包管理工具，不需要實現下載瞭然後放到本地lib庫中，和 nodejs 的 npm, php 的 compser 一樣。

<dependencies>
    <dependency>
        <groupId>io.netty</groupId>
        <artifactId>netty-all</artifactId>
        <version>5.0.0.Alpha2</version>
    </dependency>
    <dependency>
        <groupId>com.jcraft</groupId>
        <artifactId>jzlib</artifactId>
        <version>1.1.2</version>
    </dependency>
    <dependency>
        <groupId>org.json</groupId>
        <artifactId>json</artifactId>
        <version>20141113</version>
    </dependency>
    <dependency>
        <groupId>commons-codec</groupId>
        <artifactId>commons-codec</artifactId>
        <version>1.10</version>
    </dependency>
</dependencies>

建立伺服器

package net.mengkang;
 
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
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;
 
 
public final class WebSocketServer {
 
    private static final int PORT = 8083;
 
    public static void main(String[] args) throws Exception {
 
        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());
 
            Channel ch = b.bind(PORT).sync().channel();
            ch.closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

package net.mengkang;
 
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.extensions.compression.WebSocketServerCompressionHandler;
 
 
public class WebSocketServerInitializer extends ChannelInitializer<SocketChannel> {
 
    @Override
    public void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
 
        pipeline.addLast(new HttpServerCodec());
        pipeline.addLast(new HttpObjectAggregator(65536));
        pipeline.addLast(new WebSocketServerCompressionHandler());
        pipeline.addLast(new WebSocketServerHandler());
    }
}

處理長連線

下面程式中最的處理在握手階段handleHttpRequest，裡面處理引數的判斷，使用者的認證，登入使用者表的維護，直播房間表維護。詳細的請大家對照程式碼來瀏覽。

握手完成之後的訊息傳遞則在handleWebSocketFrame中處理。

整理的執行流程，大家可以對各個方法打斷點予以除錯，就會很清楚整個執行的脈絡啦。

package net.mengkang;
 
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http.websocketx.*;
import io.netty.util.CharsetUtil;
import io.netty.util.concurrent.GlobalEventExecutor;
import net.mengkang.dto.Response;
import net.mengkang.entity.Client;
import net.mengkang.service.MessageService;
import net.mengkang.service.RequestService;
import org.json.JSONObject;
 
import java.util.HashMap;
import java.util.List;
import java.util.Map;
 
import static io.netty.handler.codec.http.HttpHeaderNames.HOST;
import static io.netty.handler.codec.http.HttpMethod.GET;
import static io.netty.handler.codec.http.HttpResponseStatus.*;
import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
 
public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> {
 
    // websocket 服務的 uri
    private static final String WEBSOCKET_PATH = "/websocket";
 
    // 一個 ChannelGroup 代表一個直播頻道
    private static Map<Integer, ChannelGroup> channelGroupMap = new HashMap<>();
 
    // 本次請求的 code
    private static final String HTTP_REQUEST_STRING = "request";
 
    private Client client = null;
 
    private WebSocketServerHandshaker handshaker;
 
    @Override
    public void messageReceived(ChannelHandlerContext ctx, Object msg) {
        if (msg instanceof FullHttpRequest) {
            handleHttpRequest(ctx, (FullHttpRequest) msg);
        } else if (msg instanceof WebSocketFrame) {
            handleWebSocketFrame(ctx, (WebSocketFrame) msg);
        }
    }
 
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) {
        ctx.flush();
    }
 
    private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) {
        // Handle a bad request.
        if (!req.decoderResult().isSuccess()) {
            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST));
            return;
        }
 
        // Allow only GET methods.
        if (req.method() != GET) {
            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, FORBIDDEN));
            return;
        }
 
        if ("/favicon.ico".equals(req.uri()) || ("/".equals(req.uri()))) {
            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND));
            return;
        }
 
        QueryStringDecoder queryStringDecoder = new QueryStringDecoder(req.uri());
        Map<String, List<String>> parameters = queryStringDecoder.parameters();
 
        if (parameters.size() == 0 || !parameters.containsKey(HTTP_REQUEST_STRING)) {
            System.err.printf(HTTP_REQUEST_STRING + "引數不可預設");
            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND));
            return;
        }
 
        client = RequestService.clientRegister(parameters.get(HTTP_REQUEST_STRING).get(0));
        if (client.getRoomId() == 0) {
            System.err.printf("房間號不可預設");
            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND));
            return;
        }
 
        // 房間列表中如果不存在則為該頻道,則新增一個頻道 ChannelGroup
        if (!channelGroupMap.containsKey(client.getRoomId())) {
            channelGroupMap.put(client.getRoomId(), new DefaultChannelGroup(GlobalEventExecutor.INSTANCE));
        }
        // 確定有房間號,才將客戶端加入到頻道中
        channelGroupMap.get(client.getRoomId()).add(ctx.channel());
 
        // Handshake
        WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(getWebSocketLocation(req), null, true);
        handshaker = wsFactory.newHandshaker(req);
        if (handshaker == null) {
            WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
        } else {
            ChannelFuture channelFuture = handshaker.handshake(ctx.channel(), req);
 
            // 握手成功之後,業務邏輯
            if (channelFuture.isSuccess()) {
                if (client.getId() == 0) {
                    System.out.println(ctx.channel() + " 遊客");
                    return;
                }
 
            }
        }
    }
 
    private void broadcast(ChannelHandlerContext ctx, WebSocketFrame frame) {
 
        if (client.getId() == 0) {
            Response response = new Response(1001, "沒登入不能聊天哦");
            String msg = new JSONObject(response).toString();
            ctx.channel().write(new TextWebSocketFrame(msg));
            return;
        }
 
        String request = ((TextWebSocketFrame) frame).text();
        System.out.println(" 收到 " + ctx.channel() + request);
 
        Response response = MessageService.sendMessage(client, request);
        String msg = new JSONObject(response).toString();
        if (channelGroupMap.containsKey(client.getRoomId())) {
            channelGroupMap.get(client.getRoomId()).writeAndFlush(new TextWebSocketFrame(msg));
        }
 
    }
 
    private void handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) {
 
        if (frame instanceof CloseWebSocketFrame) {
            handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());
            return;
        }
        if (frame instanceof PingWebSocketFrame) {
            ctx.channel().write(new PongWebSocketFrame(frame.content().retain()));
            return;
        }
        if (!(frame instanceof TextWebSocketFrame)) {
            throw new UnsupportedOperationException(String.format("%s frame types not supported", frame.getClass().getName()));
        }
 
        broadcast(ctx, frame);
    }
 
    private static void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, FullHttpResponse res) {
        if (res.status().code() != 200) {
            ByteBuf buf = Unpooled.copiedBuffer(res.status().toString(), CharsetUtil.UTF_8);
            res.content().writeBytes(buf);
            buf.release();
            HttpHeaderUtil.setContentLength(res, res.content().readableBytes());
        }
 
        ChannelFuture f = ctx.channel().writeAndFlush(res);
        if (!HttpHeaderUtil.isKeepAlive(req) || res.status().code() != 200) {
            f.addListener(ChannelFutureListener.CLOSE);
        }
    }
 
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }
 
    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        Channel incoming = ctx.channel();
        System.out.println("收到" + incoming.remoteAddress() + " 握手請求");
    }
 
    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        if (client != null && channelGroupMap.containsKey(client.getRoomId())) {
            channelGroupMap.get(client.getRoomId()).remove(ctx.channel());
        }
    }
 
    private static String getWebSocketLocation(FullHttpRequest req) {
        String location = req.headers().get(HOST) + WEBSOCKET_PATH;
        return "ws://" + location;
    }
}

客戶端程式

<html>
<head><title></title></head>
<body>
<script type="text/javascript">
var socket;
if (!window.WebSocket) {
  window.WebSocket = window.MozWebSocket;
}
if (window.WebSocket) {
  socket = new WebSocket("ws://localhost:8083/websocket/?request=e2lkOjE7cmlkOjI2O3Rva2VuOiI0MzYwNjgxMWM3MzA1Y2NjNmFiYjJiZTExNjU3OWJmZCJ9");
  socket.onmessage = function(event) {
      console.log(event.data);
  };
  socket.onopen = function(event) {
    console.log("websocket 開啟了");
  };
  socket.onclose = function(event) {
    console.log("websocket 關閉了");
  };
}
 
function send(message) {
  if (!window.WebSocket) { return; }
  if (socket.readyState == WebSocket.OPEN) {
    socket.send(message);
  } else {
    alert("The socket is not open.");
  }
}
</script>
<form onsubmit="return false;">
  <input type="text" name="message" value="Hello, World!"/>
  <input type="button" value="Send Web Socket Data" onclick="send(this.form.message.value)" />
</form>
</body>
</html>

php -r "echo base64_encode(`{id:1;rid:26;token:"xxx"}`);"