先來(lái)完成一個(gè)最簡(jiǎn)單的httprequest和httpresponse的實(shí)現(xiàn)策幼。

客戶端

NioEventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(workerGroup)
                    .channel(NioSocketChannel.class)
                    .option(ChannelOption.SO_KEEPALIVE, true)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            socketChannel.pipeline().addLast(new HttpRequestEncoder());//客戶端對(duì)發(fā)送的httpRequest進(jìn)行編碼
                            socketChannel.pipeline().addLast(new HttpResponseDecoder());//客戶端需要對(duì)服務(wù)端返回的httpresopnse解碼
                            // socketChannel.pipeline().addLast(new HttpClientCodec());//HttpClientCodec()包含了上面兩種
                            socketChannel.pipeline().addLast(new HttpClientDealing());
                        }
                    });

            Channel channel = bootstrap.connect("127.0.0.1", 8080).sync().channel();

            URI uri = new URI("http://127.0.0.1:8080");
            DefaultFullHttpRequest httpRequest = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, uri.toASCIIString(), Unpooled.wrappedBuffer(msg.getBytes("UTF-8")));//生成一個(gè)默認(rèn)的httpRequest。

            httpRequest.headers().set(HttpHeaders.Names.HOST, "127.0.0.1");
            httpRequest.headers().set(HttpHeaders.Names.CONNECTION, HttpHeaders.Values.KEEP_ALIVE);
            httpRequest.headers().set(HttpHeaders.Names.CONTENT_LENGTH, httpRequest.content().readableBytes());//可以在httpRequest.headers中設(shè)置各種需要的信息。

            channel.writeAndFlush(httpRequest).sync();//發(fā)送

            channel.closeFuture().sync();

        } finally {
            workerGroup.shutdownGracefully();
        }
    }

    private static class HttpClientDealing extends ChannelInboundHandlerAdapter {
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            if(msg instanceof HttpResponse){
                System.out.println(msg.toString());//打印服務(wù)器返回的httpResponse
            }

            if(msg instanceof HttpContent) {
                System.out.println(msg.toString());
            }
        }
    }

服務(wù)端

NioEventLoopGroup bossGroup = new NioEventLoopGroup();
        NioEventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                         //   socketChannel.pipeline().addLast(new HttpServerCodec());
                            socketChannel.pipeline().addLast(new HttpRequestDecoder());//服務(wù)器添加httpRequest解碼
                            socketChannel.pipeline().addLast(new HttpResponseEncoder());//服務(wù)器添加httpResponse編碼
                            socketChannel.pipeline().addLast(new HttpServerDataDealing());
                        }
                    });

            Channel channel = serverBootstrap.bind(8080).sync().channel();

            channel.closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }

    private static class HttpServerDataDealing extends ChannelInboundHandlerAdapter {
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            if(msg instanceof HttpRequest)
            {
                System.out.println(msg.toString());//打印httpRequest
            }

            if(msg instanceof HttpContent)
            {
                System.out.println(msg.toString());
            }

            HttpResponse httpResponse = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, Unpooled.wrappedBuffer("hello client".getBytes()));//建立httpResponse
            httpResponse.headers().add(HttpHeaders.Names.CONTENT_TYPE, "text/plain");
            httpResponse.headers().add(HttpHeaders.Names.CONTENT_LENGTH, 11);

            ctx.writeAndFlush(httpResponse);//返回響應(yīng)的httpResponse
        }
    }

如果只是發(fā)送簡(jiǎn)單的http請(qǐng)求以及響應(yīng)垃沦，其實(shí)非常簡(jiǎn)單。但是為了完成功能開(kāi)發(fā)用押，一般會(huì)在http頭中加入一定的消息列表用于表示此次請(qǐng)求的一些參數(shù)

get方法和post方法的區(qū)別

根據(jù)名稱即可得知，這兩種方法在設(shè)計(jì)的時(shí)候get就是為了獲取資源舰讹，而post是為了發(fā)送資源
在自己機(jī)子上隨便抓了一個(gè)http的get請(qǐng)求如下：

get方法

這里包含了get請(qǐng)求協(xié)議和Cookie的信息茅姜。但是沒(méi)有body，Post包沒(méi)想到怎么抓就沒(méi)有示例了月匣。其實(shí)get和post在內(nèi)容上的區(qū)別就是post多了一個(gè)body钻洒，即在httpheaders下面還有一段內(nèi)容，用于保存http提交的信息桶错。表現(xiàn)在netty代碼上如下所示

get方法

        HttpRequest request = new DefaultHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, uriGet.toASCIIString());
        HttpHeaders headers = request.headers();
        headers.set(HttpHeaderNames.HOST, host);
        headers.set(HttpHeaderNames.CONNECTION, HttpHeaderValues.CLOSE);
        headers.set(HttpHeaderNames.ACCEPT_ENCODING, HttpHeaderValues.GZIP + "," + HttpHeaderValues.DEFLATE);

        headers.set(HttpHeaderNames.ACCEPT_CHARSET, "ISO-8859-1,utf-8;q=0.7,*;q=0.7");
        headers.set(HttpHeaderNames.ACCEPT_LANGUAGE, "fr");
        headers.set(HttpHeaderNames.REFERER, uriSimple.toString());
        headers.set(HttpHeaderNames.USER_AGENT, "Netty Simple Http Client side");
        headers.set(HttpHeaderNames.ACCEPT, "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");

        // send request
        channel.writeAndFlush(request);

post方法

        HttpDataFactory factory = new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE); // Disk if MINSIZE exceed
        // Prepare the HTTP request.
        HttpRequest request = new DefaultHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.POST, uriSimple.toASCIIString());

        // Use the PostBody encoder
        HttpPostRequestEncoder bodyRequestEncoder =
                new HttpPostRequestEncoder(factory, request, false);  // false => not multipart
        //可以給body添加文件等
        bodyRequestEncoder.addBodyFileUpload("myfile", file, "application/x-zip-compressed", false);
        // it is legal to add directly header or cookie into the request until finalize
        //這部分headers和get方法一樣
        for (Entry<String, String> entry : headers) {
            request.headers().set(entry.getKey(), entry.getValue());
        }

        // finalize request
        request = bodyRequestEncoder.finalizeRequest();

        // send request
        channel.write(request);

post增加的內(nèi)容

 HttpDataFactory factory = new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE); 
        HttpPostRequestEncoder bodyRequestEncoder =
                new HttpPostRequestEncoder(factory, request, false);  // false => not multipart
 bodyRequestEncoder.addBodyFileUpload("myfile", file, "application/x-zip-compressed", false);
  request = bodyRequestEncoder.finalizeRequest();

post方法利用HttpPostRequestEncoder編碼body信息航唆，然后加入到post消息中進(jìn)行發(fā)送。