netty websocket协议开发

websocket的好处我们就不用多说了，就是用于解决长连接、服务推送等需要的一种技术。

以下我们来看一个例子:

 package com.ming.netty.http.websocket;

 import java.net.InetSocketAddress;

 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
 import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 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;

 public class WebSocketServer {

     public static void main(String[] args) {
         new WebSocketServer().run("127.0.0.1", 8500);
     }

     public void run(String addr,int port){
         EventLoopGroup bossGroup = new NioEventLoopGroup();
         EventLoopGroup workerGroup = new NioEventLoopGroup();
         try {
              ServerBootstrap b=new ServerBootstrap();
               b.group(bossGroup, workerGroup)
              .channel(NioServerSocketChannel.class)
              .option(ChannelOption.SO_BACKLOG, 128)
              .childOption(ChannelOption.SO_KEEPALIVE, true)
              .childHandler(new WebSocketServerHandlerInitializer()); 

               ChannelFuture f=b.bind(new InetSocketAddress(addr, port)).sync();
               System.out.println("启动服务器:"+f.channel().localAddress());
               //等等服务器端监听端口关闭
               f.channel().closeFuture().sync();

         } catch (Exception e) {
             e.printStackTrace();
         }finally{
             bossGroup.shutdownGracefully();
             workerGroup.shutdownGracefully();
         }
     }

     protected class WebSocketServerHandlerInitializer extends ChannelInitializer<SocketChannel>{

         @Override
         protected void initChannel(SocketChannel ch) throws Exception {
             ChannelPipeline pipeline = ch.pipeline();
             pipeline.addLast(new HttpServerCodec());
             pipeline.addLast(new HttpObjectAggregator(64*1024));
             pipeline.addLast(new ChunkedWriteHandler());
             pipeline.addLast(new HttpRequestHandler("/ws"));
             pipeline.addLast(new WebSocketServerProtocolHandler("/ws"));
             pipeline.addLast(new TextWebSocketFrameHandler());
         }

     }
 }

 package com.ming.netty.http.websocket;

 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.DefaultFileRegion;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.DefaultHttpResponse;
 import io.netty.handler.codec.http.FullHttpRequest;
 import io.netty.handler.codec.http.FullHttpResponse;
 import io.netty.handler.codec.http.HttpHeaders;
 import io.netty.handler.codec.http.HttpResponse;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
 import io.netty.handler.codec.http.LastHttpContent;
 import io.netty.handler.ssl.SslHandler;
 import io.netty.handler.stream.ChunkedNioFile;

 import java.io.File;
 import java.io.IOException;
 import java.io.RandomAccessFile;
 import java.net.URISyntaxException;
 import java.net.URL;

 public class HttpRequestHandler extends SimpleChannelInboundHandler<FullHttpRequest> {

     private final String wsUri;
     private static final File INDEX;

     // static HTTP request handling operation.
     static {
         URL location = HttpRequestHandler.class.getProtectionDomain().getCodeSource().getLocation();
         try {
            String path = location.toURI() + "WebSocketClient.html";
            path = !path.contains("file:") ? path : path.substring(5);
            INDEX = new File("D:\\javaPro\\workspace\\NettyTest\\resources\\WebsocketChatClient.html");
          } catch (URISyntaxException e) {
            throw new IllegalStateException("Unable to locate WebsocketChatClient.html", e);
         }
   }

      public HttpRequestHandler(String wsUri) {
          this.wsUri = wsUri;
      }

  @Override
 protected void messageReceived(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception {
      channelRead(ctx,request);

 }

 public void channelRead(ChannelHandlerContext ctx, FullHttpRequest request)
    throws Exception {
   if (wsUri.equalsIgnoreCase(request.getUri())) {
    ctx.fireChannelRead(request.retain());
   } else {
    if (HttpHeaders.is100ContinueExpected(request)) {
     send100Continue(ctx);
    }

    RandomAccessFile file = new RandomAccessFile(INDEX, "r");
    HttpResponse response = new DefaultHttpResponse(
      request.getProtocolVersion(), HttpResponseStatus.OK);
      response.headers().set(HttpHeaders.Names.CONTENT_TYPE,
      "text/html; charset=UTF-8");

    boolean keepAlive = HttpHeaders.isKeepAlive(request);
    if (keepAlive) {
     response.headers().set(HttpHeaders.Names.CONTENT_LENGTH,  file.length());
     response.headers().set(HttpHeaders.Names.CONNECTION, HttpHeaders.Values.KEEP_ALIVE);
    }
    ctx.write(response);

    if (ctx.pipeline().get(SslHandler.class) == null) {
     ctx.write(new DefaultFileRegion(file.getChannel(), 0, file.length()));
    } else {
     ctx.write(new ChunkedNioFile(file.getChannel()));
    }
    ChannelFuture future = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
    if (!keepAlive) {
     future.addListener(ChannelFutureListener.CLOSE);
    }

    file.close();
   }
  }

  private static void send100Continue(ChannelHandlerContext ctx) {
   FullHttpResponse response = new DefaultFullHttpResponse(
     HttpVersion.HTTP_1_1, HttpResponseStatus.CONTINUE);
   ctx.writeAndFlush(response);
  }

  @Override
  public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
    throws Exception {
   Channel incoming = ctx.channel();
   System.out.println("Client:" + incoming.remoteAddress() + "异常");

   // 当出现异常就关闭连接
   cause.printStackTrace();
   ctx.close();
  }

 }

 package com.ming.netty.http.websocket;

 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.channel.group.ChannelGroup;
 import io.netty.channel.group.DefaultChannelGroup;
 import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
 import io.netty.util.concurrent.GlobalEventExecutor;

 public class TextWebSocketFrameHandler extends SimpleChannelInboundHandler<TextWebSocketFrame>  {

     public static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);

     @Override
     public void channelActive(ChannelHandlerContext ctx) throws Exception {
           Channel incoming = ctx.channel();
           System.out.println("Client:" + incoming.remoteAddress() + "在线");
     }

     @Override
     public void channelInactive(ChannelHandlerContext ctx) throws Exception {
         Channel incoming = ctx.channel();
         System.out.println("Client:" + incoming.remoteAddress() + "掉线");
     }

     @Override
     public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
           Channel incoming = ctx.channel();
           for (Channel channel : channels) {
            channel.writeAndFlush(new TextWebSocketFrame("[SERVER] - "  + incoming.remoteAddress() + " 加入"));
           }
           channels.add(ctx.channel());
           System.out.println("Client:" + incoming.remoteAddress() + "加入");
     }

     @Override
     public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
         Channel incoming = ctx.channel();
         for (Channel channel : channels) {
           channel.writeAndFlush(new TextWebSocketFrame("[SERVER] - "  + incoming.remoteAddress() + " 离开"));
         }
         System.out.println("Client:" + incoming.remoteAddress() + "离开");
         channels.remove(ctx.channel());
     }

     @Override
     protected void messageReceived(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {
         Channel incoming = ctx.channel();
           for (Channel channel : channels) {
            if (channel != incoming) {
             //channel.writeAndFlush(new TextWebSocketFrame("[" + incoming.remoteAddress() + "]" + msg.text()));
            } else {
             //返送给指定的
             channel.writeAndFlush(new TextWebSocketFrame("[服务器端返回]：" + msg.text()));

             //output current message to context.
             StringBuffer sb = new StringBuffer();
             sb.append(incoming.remoteAddress()).append("->").append(msg.text());
             System.out.println(sb.toString());
            }
           }

     }

     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
         Channel incoming = ctx.channel();
         System.out.println("Client:" + incoming.remoteAddress() + "异常");
         // 当出现异常就关闭连接
         cause.printStackTrace();
         ctx.close();
     }

 }

 <!DOCTYPE html>
 <html>
 <head>
 <meta charset="UTF-8">
 <title>WebSocket Chat</title>
 </head>
 <body>
     <script type="text/javascript">
         var socket;
         if (!window.WebSocket) {
             window.WebSocket = window.MozWebSocket;
         }
         if (window.WebSocket) {
             socket = new WebSocket("ws://127.0.0.1:8500/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 + "连接被关闭";
             };
         } else {
             alert("你的浏览器不支持 WebSocket！");
         }

         function send(message) {
             if (!window.WebSocket) {
                 return;
             }
             if (socket.readyState == WebSocket.OPEN) {
                 socket.send(message);
             } else {
                 alert("连接没有开启.");
             }
         }
     </script>
     <form onsubmit="return false;">
         <h3>WebSocket 聊天室：</h3>
         <textarea id="responseText" style="width: 500px; height: 300px;"></textarea>
         <br>
         <input type="text" name="message"  style="width: 300px" value="Welcome to www.waylau.com">
         <input type="button" value="发送消息" onclick="send(this.form.message.value)">
         <input type="button" onclick="javascript:document.getElementById('responseText').value=''" value="清空聊天记录">
     </form>
     <br>
     <br> 

 </body>
 </html>

运行服务器，然后在浏览器输入：127.0.0.1:8500 就可以看见一个简单的聊天室效果了.