netty学习记录（实例）

使用jar包为netty-all-5.0.0.Alpha1.jar

地址为：http://central.maven.org/maven2/io/netty/netty-all/5.0.0.Alpha1/netty-all-5.0.0.Alpha1.jar

创建一个nettyConfig配置文件，存储整个工程的全局配置

package com.rg2.netty;

import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.util.concurrent.GlobalEventExecutor;

/**
 * 存储整个工程的全局配置
 * @author chengli
 *
 */
public class NettyConfig {

    /**
     * 存储每一个客户端接入进来时的channel对象
     */
    public static ChannelGroup group = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
}

然后再加上一个 接受/处理/响应客户端websocket请求的核心业务处理类

package com.rg2.netty;

import java.util.Date;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
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;

/**
 * 接受/处理/响应客户端websocket请求的核心业务处理类
 * @author chengli
 *
 */
public class MyWebSocketHandler extends SimpleChannelInboundHandler<Object> {

    private WebSocketServerHandshaker handshaker;
    private static final String WEB_SOCKET_URL = "ws://localhost:8888/websocket";
    
    //服务端处理客户端websocket请求的核心方法
    @Override
    protected void messageReceived(ChannelHandlerContext context, Object msg) throws Exception {
        //处理客户端向服务端发起http握手请求的业务
        if(msg instanceof FullHttpRequest){
            handHttpRequest(context, (FullHttpRequest)msg);
        }else if(msg instanceof WebSocketFrame){//处理websocket连接业务
            handWebsocketFrame(context, (WebSocketFrame)msg);
        }
    }
    
    /**
     * 处理客户端和服务端之前的websocket业务
     * @param ctx
     * @param frame
     */
    private void handWebsocketFrame(ChannelHandlerContext ctx,WebSocketFrame frame){
        //判断是否是关闭websocket的指令
        if(frame instanceof CloseWebSocketFrame){
            handshaker.close(ctx.channel(), (CloseWebSocketFrame)frame.retain());
        }
        //判断是否是ping消息
        if(frame instanceof PingWebSocketFrame){
            ctx.channel().write(new PongWebSocketFrame(frame.content().retain()));
            return;
        }
        
        //判断是否是二进制消息，如果是二进制消息，抛出异常
        if(!(frame instanceof TextWebSocketFrame)){
            System.out.println("目前我们不支持二进制消息");
            throw new RuntimeException("【"+this.getClass().getName()+"】不支持消息");
        }
        //返回应答消息
        //获取客户端向服务端发送的消息
        String request = ((TextWebSocketFrame)frame).text();
        System.out.println("服务端收到客户端的消息=====>>"+request);
        
        TextWebSocketFrame tws = new TextWebSocketFrame(new Date().toString()
                                                        + ctx.channel().id()
                                                        + "===>>"
                                                        + request);
        
        //群发，服务端向每个连接上来的客户端群发消息
        NettyConfig.group.writeAndFlush(tws);
    }
    
    /**
     * 处理客户端向服务端发起的http握手请求的业务
     * @param ctx
     * @param req
     */
    private void handHttpRequest(ChannelHandlerContext ctx,FullHttpRequest req){
        //netty-all-5.0.0.Alpha2不具有getDecoderResult()方法
        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(WEB_SOCKET_URL, null, false);
        handshaker = wsFactory.newHandshaker(req);
        if (handshaker == null) {
            WebSocketServerHandshakerFactory.sendUnsupportedWebSocketVersionResponse(ctx.channel());
        }else{
            handshaker.handshake(ctx.channel(), req);
        }
    }

    /**
     * 服务端向客户端响应消息
     * @param ctx
     * @param req
     * @param res
     */
    private void sendHttpResponse(ChannelHandlerContext ctx,FullHttpRequest req,DefaultFullHttpResponse res){
        if(res.getStatus().code()!=200){
            ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(), CharsetUtil.UTF_8);
            res.content().writeBytes(buf);
            buf.release();
        }
        //服务端向客户端发送数据
        ChannelFuture f = ctx.channel().writeAndFlush(res);
        if(res.getStatus().code()!=200){
            f.addListener(ChannelFutureListener.CLOSE);
        }
    }
    
    //客户端与服务端创建连接的时候调用
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
//        super.channelActive(ctx);
        NettyConfig.group.add(ctx.channel());
        System.out.println("客户端和服务端连接开启...");
    }

    //客户端与服务端断开连接的时候调用
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
//        super.channelInactive(ctx);
        NettyConfig.group.remove(ctx.channel());
        System.out.println("客户端和服务端连接关闭...");
    }

    //服务端接受客户端发送过来的数据结束之后调用
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
//        super.channelReadComplete(ctx);
        ctx.flush();
    }

    //工程出现异常的时候调用
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
//        super.exceptionCaught(ctx, cause);
        cause.printStackTrace();
        ctx.close();
    }

}

要处理 初始化你连接时候的各个组件

package com.rg2.netty;

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;

/**
 * 初始化你连接时候的各个组件
 * @author chengli
 *
 */
public class MyWebSocketChannelHandler 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 MyWebSocketHandler());
    }

}

启动方法：

package com.rg2.netty;

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;

/**
 * 程序的入口，负责启动应用
 * @author chengli
 *
 */
public class Main {

    public static void main(String[] args) {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workGroup = new NioEventLoopGroup();
        
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workGroup);
            b.channel(NioServerSocketChannel.class);
            b.childHandler(new MyWebSocketChannelHandler());
            System.out.println("服务端开启等待客户端连接...");
            Channel ch = b.bind(8888).sync().channel();
            ch.closeFuture().sync();
            
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //优雅的退出程序
            bossGroup.shutdownGracefully();
            workGroup.shutdownGracefully();
        }
    }

}

静态页面代码

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>WebSocket客户端</title>
        <script type="text/javascript">
            var socket;
            debugger;
            if(!window.WebSocket){
                window.WebSocket = window.MozWebSocket;
            }
            if(window.WebSocket){
                socket = new WebSocket("ws://localhost:8888/websocket");
                socket.onmessage = function(event){
                    var ta = document.getElementById("responseContent");
                    ta.value += event.data + "
";
                };
                
                socket.onopen = function(event){
                    var ta = document.getElementById("responseContent");
                    ta.value = "您当前的浏览器支持WebSocket，请进行后续操作
";
                };
                
                socket.onclose = function(event){
                    var ta = document.getElementById("responseContent");
                    ta.value = "";
                    ta.value = "WebSocket连接已经关闭
";
                }
            }else{
                alert("您的浏览器不支持WebSocket");
            }
            
            function send(message){
                if(!window.WebSocket){
                    return;
                }
                if(socket.readyState == WebSocket.OPEN){
                    socket.send(message);
                }else{
                    alert("WebSocket连接没有建立成功");
                }
            }
        </script>
    </head>
    <body>
        <form>
            <input type="text" name="message" value="" />
            <br />
            <br />
            <input type="submit" value="发送WebSocket请求消息" onclick="send(this.form.message.value)" />
            <hr color="#FF0000" />
            <h2>客户端接收到服务端返回的应答消息</h2>
            <textarea id="responseContent" style=" 1024px;height: 300px;"></textarea>
        </form>
    </body>
</html>