實現簡單WebSocket服務器

使用Netty框架實現簡單WebSocket服務器

NettyServer.java

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
public class NettyServer {
    public static void main(String[] args) {
        
        new NettyServer().run();
    }
    
    public void run(){
        
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workGroup = new NioEventLoopGroup();
        
        try {
            
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workGroup);
            b.channel(NioServerSocketChannel.class);
            b.childHandler(new ChildChannelHandler());
            
            System.out.println("服務端開啓等待客戶端鏈接 ... ...");
            
            Channel ch = b.bind(7397).sync().channel();
            
            ch.closeFuture().sync();
            
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            bossGroup.shutdownGracefully();
            workGroup.shutdownGracefully();
        }
        
    }
    
}

ChildChannelHandler.java

import io.netty.channel.ChannelInitializer;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.stream.ChunkedWriteHandler;
public class ChildChannelHandler 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 MyWebSocketServerHandler());
    }
}

Global.java

import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.util.concurrent.GlobalEventExecutor;
public class Global {
    public static ChannelGroup group = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
    
}

MyWebSocketServerHandler.java

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http.websocketx.CloseWebSocketFrame;
import io.netty.handler.codec.http.websocketx.PingWebSocketFrame;
import io.netty.handler.codec.http.websocketx.PongWebSocketFrame;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketServerHandshaker;
import io.netty.handler.codec.http.websocketx.WebSocketServerHandshakerFactory;
import io.netty.util.CharsetUtil;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

public class MyWebSocketServerHandler extends
        SimpleChannelInboundHandler<Object> {
    private static final Logger logger = Logger
            .getLogger(WebSocketServerHandshaker.class.getName());
    
    private static final Map<String,Channel> allContext=new HashMap<String, Channel>(16);
    private WebSocketServerHandshaker handshaker;
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        // 添加
        Global.group.add(ctx.channel());
        System.out.println("客戶端與服務端鏈接開啓");
    }
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        // 移除
        Global.group.remove(ctx.channel());
        System.out.println("客戶端與服務端鏈接關閉");
    }
    
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, Object msg)
            throws Exception {
        if (msg instanceof FullHttpRequest) {
            handleHttpRequest(ctx, ((FullHttpRequest) msg));
        } else if (msg instanceof WebSocketFrame) {
            handlerWebSocketFrame(ctx, (WebSocketFrame) msg);
        }
    }
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }
    private void handlerWebSocketFrame(ChannelHandlerContext ctx,
            WebSocketFrame frame) {
        // 判斷是否關閉鏈路的指令
        if (frame instanceof CloseWebSocketFrame) {
            handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame
                    .retain());
        }
        // 判斷是否ping消息
        if (frame instanceof PingWebSocketFrame) {
            ctx.channel().write(
                    new PongWebSocketFrame(frame.content().retain()));
            return;
        }
        // 本例程僅支持文本消息，不支持二進制消息
        if (!(frame instanceof TextWebSocketFrame)) {
            System.out.println("本例程僅支持文本消息，不支持二進制消息");
            throw new UnsupportedOperationException(String.format(
                    "%s frame types not supported", frame.getClass().getName()));
        }
        // 返回應答消息
        String request = ((TextWebSocketFrame) frame).text();
        allContext.put(request, ctx.channel());
        System.out.println("服務端收到：" + request);
        if (logger.isLoggable(Level.FINE)) {
            logger
                    .fine(String.format("%s received %s", ctx.channel(),
                            request));
        }
        TextWebSocketFrame tws = new TextWebSocketFrame(new Date().toString()
                + ctx.channel().id() + "：" + request);
        TextWebSocketFrame twsToAdmin = new TextWebSocketFrame("Message from "
            + ctx.channel().id() + "：" + request);
        // 羣發
//        Global.group.writeAndFlush(tws);
        Channel admin=allContext.get("admin");
        admin.writeAndFlush(twsToAdmin);
        // 返回【誰發的發給誰】
         ctx.channel().writeAndFlush(tws);
    }
    private void handleHttpRequest(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(
                "ws://localhost:7397/websocket", null, false);
        handshaker = wsFactory.newHandshaker(req);
        if (handshaker == null) {
            WebSocketServerHandshakerFactory
                    .sendUnsupportedWebSocketVersionResponse(ctx.channel());
        } else {
            handshaker.handshake(ctx.channel(), req);
        }
    }
    private static void sendHttpResponse(ChannelHandlerContext ctx,
            FullHttpRequest req, DefaultFullHttpResponse res) {
        // 返回應答給客戶端
        if (res.getStatus().code() != 200) {
            ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(),
                    CharsetUtil.UTF_8);
            res.content().writeBytes(buf);
            buf.release();
        }
        // 若是是非Keep-Alive，關閉鏈接
        ChannelFuture f = ctx.channel().writeAndFlush(res);
        if (!isKeepAlive(req) || res.getStatus().code() != 200) {
            f.addListener(ChannelFutureListener.CLOSE);
        }
    }
    private static boolean isKeepAlive(FullHttpRequest req) {
        return false;
    }
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
            throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>無標題文檔</title>
</head>
  </head>
  <script type="text/javascript">
  var socket;
  
  
  if(!window.WebSocket){
 
	  window.WebSocket = window.MozWebSocket;
  }
 
  if(window.WebSocket){
	  socket = new WebSocket("ws://localhost:7397/websocket");
	  
	  socket.onmessage = function(event){
 
			var ta = document.getElementById('responseText');
			ta.value += event.data+"\r\n";
	  };
 
	  socket.onopen = function(event){
 
			var ta = document.getElementById('responseText');
			ta.value = "打開WebSoket 服務正常，瀏覽器支持WebSoket!"+"\r\n";
			
	  };
 
	  socket.onclose = function(event){
 
			var ta = document.getElementById('responseText');
			ta.value = "";
			ta.value = "WebSocket 關閉"+"\r\n";
	  };
  }else{
		alert("您的瀏覽器不支持WebSocket協議！");
  }
 
  function send(message){
	if(!window.WebSocket){return;}
	if(socket.readyState == WebSocket.OPEN){
		socket.send(message);
	}else{
		alert("WebSocket 鏈接沒有創建成功！");
	}
	
  }
	  
  </script>
  <body>
    <form onSubmit="return false;">
    	<input type = "text" name="message" value="Netty The Sinper"/>
    	<br/><br/>
    	<input type="button" value="發送 WebSocket 請求消息" onClick="send(this.form.message.value)"/>
    	<hr color="blue"/>
    	<h3>服務端返回的應答消息</h3>
    	<textarea id="responseText" style="width: 1024px;height: 300px;"></textarea>
    </form>
  </body>
</html>