Netty實現聊天通信（4.0）

以下是netty4.0的代碼，如果是5.0的代碼請參考 —>
Netty之——基於Netty5.0高級案例NettyWebsocket
http://blog.csdn.net/l1028386804/article/details/55026558
1、Java代碼

package com.test.netty4;  

import io.netty.channel.ChannelHandlerContext;  
import io.netty.handler.codec.http.FullHttpRequest;  

public interface IHttpService {  

    void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest request);  

}  

package com.test.netty4;  

import io.netty.channel.ChannelHandlerContext;  
import io.netty.handler.codec.http.websocketx.WebSocketFrame;  

public interface IWebSocketService {  

    void handleFrame(ChannelHandlerContext ctx, WebSocketFrame frame);  

}  

package com.test.netty4;  

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelId;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.HttpHeaderNames;
import io.netty.handler.codec.http.HttpHeaders;
import io.netty.handler.codec.http.HttpMethod;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
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.handler.stream.ChunkedWriteHandler;
import io.netty.util.AttributeKey;
import io.netty.util.concurrent.GlobalEventExecutor;  


public class WebSocketServer implements IWebSocketService, IHttpService {  

    public static void main(String[] args) {  
        new WebSocketServer(9999).start();  
    }  

    // ----------------------------static fields -----------------------------  


    private static final String HN_HTTP_CODEC = "HN_HTTP_CODEC";  
    private static final String HN_HTTP_AGGREGATOR = "HN_HTTP_AGGREGATOR";  
    private static final String HN_HTTP_CHUNK = "HN_HTTP_CHUNK";  
    private static final String HN_SERVER = "HN_LOGIC";  

    // handshaker attachment key  
    private static final AttributeKey<WebSocketServerHandshaker> ATTR_HANDSHAKER = AttributeKey.newInstance("ATTR_KEY_CHANNELID");  

    private static final int MAX_CONTENT_LENGTH = 65536;  

    private static final String WEBSOCKET_UPGRADE = "websocket";  
    private static final String WEBSOCKET_CONNECTION = "Upgrade";  
    private static final String WEBSOCKET_URI_ROOT_PATTERN = "ws://%s:%d";  

    // ------------------------ member fields -----------------------  

    private String host; // 綁定的地址  
    private int port; // 綁定的端口  

    /** 
     * 保存所有WebSocket連接 
     */  
    private Map<ChannelId, Channel> channelMap = new ConcurrentHashMap<ChannelId, Channel>();  
    private ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
    private final String WEBSOCKET_URI_ROOT;  

    public WebSocketServer(int port) {  
        this("localhost", port);  
    }  

    public WebSocketServer(String host, int port) {  
        this.host = host;  
        this.port = port;  
        WEBSOCKET_URI_ROOT = String.format(WEBSOCKET_URI_ROOT_PATTERN, host, port);  
    }  

    public void start() {  
        EventLoopGroup bossGroup = new NioEventLoopGroup();  
        EventLoopGroup workerGroup = new NioEventLoopGroup();  
        ServerBootstrap b = new ServerBootstrap();  
        b.group(bossGroup, workerGroup);  
        b.channel(NioServerSocketChannel.class);  
        b.childHandler(new ChannelInitializer<Channel>() {  

            @Override  
            protected void initChannel(Channel ch) throws Exception {  
                ChannelPipeline pl = ch.pipeline();  
                // 保存該Channel的引用  
                channelGroup.add(ch);
                channelMap.put(ch.id(), ch);  
                System.out.println("new channel {}"+ ch);  
                ch.closeFuture().addListener(new ChannelFutureListener() {  

                    public void operationComplete(ChannelFuture future) throws Exception {  
                        System.out.println("channel close {}"+ future.channel());  
                        // Channel 關閉後不再引用該Channel  
                        channelMap.remove(future.channel().id());  
                    }  
                });  

                pl.addLast(HN_HTTP_CODEC, new HttpServerCodec());  
                pl.addLast(HN_HTTP_AGGREGATOR, new HttpObjectAggregator(MAX_CONTENT_LENGTH));  
                pl.addLast(HN_HTTP_CHUNK, new ChunkedWriteHandler());  
                pl.addLast(HN_SERVER, new WebSocketServerHandler(WebSocketServer.this, WebSocketServer.this));  
            }  

        });  

        try {  
            // 綁定端口  
            ChannelFuture future = b.bind(host, port).addListener(new ChannelFutureListener() {  

                public void operationComplete(ChannelFuture future) throws Exception {  
                    if (future.isSuccess()) {  
                        System.out.println("websocket started.");  
                    }  
                }  
            }).sync();  

            future.channel().closeFuture().addListener(new ChannelFutureListener() {  

                public void operationComplete(ChannelFuture future) throws Exception {  
                    System.out.println("server channel {} closed."+future.channel());  
                }  

            }).sync();  
        } catch (InterruptedException e) {  
            e.printStackTrace();
            //            logger.error(e.toString());  
        } finally {  
            bossGroup.shutdownGracefully();  
            workerGroup.shutdownGracefully();  
        }  
        System.out.println("websocket server shutdown");  
    }  

    /*  
     * @see cc.lixiaohui.demo.netty4.websocket.IHttpService#handleHttpRequest(io.netty.handler.codec.http.FullHttpRequest) 
     */  
    public void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) {  
        if (isWebSocketUpgrade(req)) { // 該請求是不是websocket upgrade請求   
            System.out.println("upgrade to websocket protocol");  

            String subProtocols = req.headers().get(HttpHeaderNames.SEC_WEBSOCKET_PROTOCOL);  

            WebSocketServerHandshakerFactory factory = new WebSocketServerHandshakerFactory(WEBSOCKET_URI_ROOT, subProtocols, false);  
            WebSocketServerHandshaker handshaker = factory.newHandshaker(req);  

            if (handshaker == null) {// 請求頭不合法, 導致handshaker沒創建成功  
                WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());  
            } else {  
                // 響應該請求  
                handshaker.handshake(ctx.channel(), req);  
                // 把handshaker 綁定給Channel, 以便後面關閉連接用  
                ctx.channel().attr(ATTR_HANDSHAKER).set(handshaker);// attach handshaker to this channel  
            }  
            return;  
        }  

        // TODO 忽略普通http請求  
        System.out.println("ignoring normal http request");  
    }  

    /* 
     * @see 
     * cc.lixiaohui.demo.netty4.websocket.IWebSocketService#handleFrame(io.netty 
     * .channel.Channel, io.netty.handler.codec.http.websocketx.WebSocketFrame) 
     */  
    public void handleFrame(ChannelHandlerContext ctx, WebSocketFrame frame) {  
        // text frame  
        if (frame instanceof TextWebSocketFrame) {  
            String text = ((TextWebSocketFrame) frame).text();  
//            TextWebSocketFrame rspFrame = new TextWebSocketFrame(text);  
            System.out.println("recieve TextWebSocketFrame from channel {}"+ ctx.channel());  
            // 發給其他所有channel  
//            for (Channel ch : channelMap.values()) {  
//                if (ctx.channel().equals(ch)) {   
//                    continue;   
//                }  
//                TextWebSocketFrame rspFrame = new TextWebSocketFrame(text);  
//                ch.writeAndFlush(rspFrame);  
//                System.out.println("write text[{}] to channel {}"+ text+ ch);  
//            }  
            TextWebSocketFrame rspFrame = new TextWebSocketFrame(text);  
            channelGroup.writeAndFlush(rspFrame);
            return;  
        }  
        // ping frame, 回覆pong frame即可  
        if (frame instanceof PingWebSocketFrame) {  
            System.out.println("recieve PingWebSocketFrame from channel {}"+ ctx.channel());  
            ctx.channel().writeAndFlush(new PongWebSocketFrame(frame.content().retain()));  
            return;  
        }  

        if (frame instanceof PongWebSocketFrame) {  
            System.out.println("recieve PongWebSocketFrame from channel {}"+ ctx.channel());  
            return;  
        }  
        // close frame,   
        if (frame instanceof CloseWebSocketFrame) {  
            System.out.println("recieve CloseWebSocketFrame from channel {}"+ ctx.channel());  
            WebSocketServerHandshaker handshaker = ctx.channel().attr(ATTR_HANDSHAKER).get();  
            if (handshaker == null) {  
                System.out.println("channel {} have no HandShaker"+ ctx.channel());  
                return;  
            }  
            handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());  
            return;  
        }  
        // 剩下的是binary frame, 忽略  
        System.out.println("unhandle binary frame from channel {}"+ctx.channel());  
    }  

    //三者與：1.GET? 2.Upgrade頭 包含websocket字符串?  3.Connection頭 包含 Upgrade字符串?  
    private boolean isWebSocketUpgrade(FullHttpRequest req) {  
        HttpHeaders headers = req.headers();  
        return req.getMethod().equals(HttpMethod.GET)   
                && headers.get(HttpHeaderNames.UPGRADE).contains(WEBSOCKET_UPGRADE)  
                && headers.get(HttpHeaderNames.CONNECTION).contains(WEBSOCKET_CONNECTION);  
    }  

}  

package com.test.netty4;  

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



public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> {  

    @SuppressWarnings("unused")  

    private IWebSocketService websocketService;  

    private IHttpService httpService;  

    public WebSocketServerHandler(IWebSocketService websocketService, IHttpService httpService) {  
        super();  
        this.websocketService = websocketService;  
        this.httpService = httpService;  
    }  

    /* 
     * @see 
     * io.netty.channel.SimpleChannelInboundHandler#channelRead0(io.netty.channel 
     * .ChannelHandlerContext, java.lang.Object) 
     */  
    @Override  
    protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {  
        if (msg instanceof FullHttpRequest) {  
            httpService.handleHttpRequest(ctx, (FullHttpRequest) msg);  
        } else if (msg instanceof WebSocketFrame) {  
            websocketService.handleFrame(ctx, (WebSocketFrame) msg);  
        }  
    }  

    /*  
     * @see io.netty.channel.ChannelInboundHandlerAdapter#channelReadComplete(io.netty.channel.ChannelHandlerContext) 
     */  
    @Override  
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {  
        ctx.flush();  
    } 


    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {

    }


}  

2、html頁面代碼

    <!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></title>  
    </head>  
      </head>  
      <script type="text/javascript">  
      var socket;  

      if(!window.WebSocket){  
          window.WebSocket = window.MozWebSocket;  
      }  

      if(window.WebSocket){  
          socket = new WebSocket("ws://localhost:9999");  
          socket.onmessage = function(event){             
                appendln("接收:" + event.data);  
          };  

          socket.onopen = function(event){  
                appendln("WebSocket 連接已建立");  

          };  

          socket.onclose = function(event){  
                appendln("WebSocket 連接已關閉");  
          };  
      }else{  
            alert("瀏覽器不支持WebSocket協議");  
      }  

      function send(message){  
        if(!window.WebSocket){return;}  
        if(socket.readyState == WebSocket.OPEN){  
            socket.send(message);  
            appendln("發送:" + message);  
        }else{  
            alert("WebSocket連接建立失敗");  
        }  

      }  

      function appendln(text) {  
        var ta = document.getElementById('responseText');  
        ta.value += text + "\r\n";  
      }  

      function clear() {  
        var ta = document.getElementById('responseText');  
        ta.value = "";  
      }  

      </script>  
      <body>  
        <form onSubmit="return false;">  
            <input type = "text" name="message" value="你好啊"/>  
            <br/><br/>  
            <input type="button" value="發送 WebSocket 請求消息" onClick="send(this.form.message.value)"/>  
            <hr/>  
            <h3>服務端返回的應答消息</h3>  
            <textarea id="responseText" style="width: 800px;height: 300px;"></textarea>  
        </form>  
      </body>  
    </html>  

3、啓動 WebSocketServer 的main方法，然後打開多個html頁面，即可實現聊天互通。更
此處是基於netty-all-4.1.12.Final.jar實現的。更詳細的介紹可自行網絡搜索。