我們下面則将一些實際場景都添加進去，比如使用者身份的驗證，遊客隻能浏覽不能發言，多房間（頻道）的聊天。
該部落格非常适合 Java 新手，非常适合作為學習 Java 的切入點，不需要考慮tomcat、spring、mybatis等。
唯一的知識點就是 maven 的基礎使用。
├── WebSocketServer.java 啟動伺服器端口監聽
├── WebSocketServerInitializer.java 初始化服務
├── WebSocketServerHandler.java 接管WebSocket資料連接配接
├── dto
│ └── Response.java 傳回給用戶端資料對象
├── entity
│ └── Client.java 每個連接配接到WebSocket服務的用戶端對象
└── service
├── MessageService.java 完成發送消息
└── RequestService.java WebSocket初始化連接配接握手時的資料處理
功能設計概述
身份認證
用戶端将使用者 id 、進入的房間的 rid、使用者 token
json_encode
，例如
{id:1;rid:21;token:'43606811c7305ccc6abb2be116579bfd'}
。然後在
base64
處理，通過參數
request
傳到伺服器，然後在伺服器做 id 和 token 的驗證（我的做法是 token 存放在redis string 5秒的過期時間）
房間表
使用一個Map
channelGroupMap
來存放各個房間（頻道），以用戶端傳握手時傳過來的 base64 字元串中擷取到定義的房間 ID，然後為該房間 ID 建立一個
ChannelGroup
（
ChannelGroup
友善對該組内的所有用戶端廣播消息）
在 pom.xml 中引入netty 5
<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
這段代碼需要了解嗎？這是 netty 的套路，可以先記住 netty 的線程模型是一個 react 的一種變型，這裡有兩個nio線程組，一個是接受用戶端的請求，一個是worker組專門處理用戶端的請求。
可以簡單的了解下面的代碼就建構了一個nginx伺服器。是以不用管。
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());
}
}
處理長連接配接
下面程式中最的處理在握手階段
handleHttpRequest
，裡面處理參數的判斷，使用者的認證，登入使用者表的維護，直播房間表維護。詳細的請大家對照代碼來浏覽。
握手完成之後的消息傳遞則在
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調試，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 ConcurrentHashMap <>();
// 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 + "參數不可預設");
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("房間号不可預設");
sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND));
return;
}
// 房間清單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));
}
// 确定有房間号,才将用戶端加入到頻道中
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;
}
}
伺服器端就寫完啦，還有一些用戶端對象的構想驗證什麼的就不一一細說了，都很簡單，都在代碼裡。下面是用戶端。
<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 打開了");
};
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 οnsubmit="return false;">
<input type="text" name="message" value="Hello, World!"/>
<input type="button" value="Send Web Socket Data" οnclick="send(this.form.message.value)" />
</form>
</body>
</html>
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