基于Netty的HTTP服务器的实现-优快云博客

本文链接：https://blog.youkuaiyun.com/isaiah282485068/article/details/105309173

HTTP协议简介

Http协议是基于TCP/IP协议基础上用于超文本传输的应用层协议，主要有以下特点：

支持C/S模式
无状态
灵活
简单，直接在browser中指定url，携带请求参数或请求消息体就可与服务器通信

Http请求消息

HTTP请求报文由3部分组成（请求行+请求头+请求体）

Http响应消息

HTTP的响应报文也由三部分组成（响应行+响应头+响应体）：

Http服务器实现

HttpServerCodec是对http消息编码和解码，相当于：HttpRequestDecoder和HttpResponseEncoder。因此在pipline.addLast时要么开始就添加一个HttpServerCodec，或HttpRequestDecoder和HttpResponseEncoder分开添加。

public class HttpServer {
    public static void main(String[] args) throws Exception {
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workGoup = new NioEventLoopGroup(8);
        try{
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap
                    .group(bossGroup, workGoup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        public void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline pipeline = ch.pipeline();
                            //  HttpServerCodec 是 netty 提供的处理 http 的 编-解码器
                            pipeline.addLast("httpServerCodec", new HttpServerCodec());
                            // 增加一个自定义的 handler
                            pipeline.addLast("MyHttpServerHandler", new MyHttpServerHandler());
                        }
                    });
            ChannelFuture channelFuture = serverBootstrap.bind(7777).sync();
            channelFuture.channel().closeFuture().sync();
        }finally {
            bossGroup.shutdownGracefully();
            workGoup.shutdownGracefully();
        }
    }
}

业务处理器

public class MyHttpServerHandler extends SimpleChannelInboundHandler<HttpObject> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
        if (msg instanceof HttpRequest){

            System.out.println("pipeline hashcode" + ctx.pipeline().hashCode() + " myHttpServerHandler hash=" + this.hashCode());
            System.out.println("msg 类型：" + msg.getClass());
            System.out.println("客户端地址：" + ctx.channel().remoteAddress());

            HttpRequest httpRequest = (HttpRequest) msg;
            String uri = httpRequest.uri();
            System.out.println("uri" + uri);
            URI httpUri = new URI(uri);
            // 处理请求
            if ("/list".equals(httpUri.getPath())){
                System.out.println("调用list接口");
                return ;
            }
            if ("/add".equals(httpUri.getPath())){
                System.out.println("调用add接口");
                return ;
            }
            ByteBuf content = Unpooled.copiedBuffer("对不起, 资源没有找到！", CharsetUtil.UTF_8);
            // 构建一个响应
            DefaultFullHttpResponse httpResponse = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, content);
            httpResponse.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain");
            httpResponse.headers().set(HttpHeaderNames.CONTENT_LENGTH, content.readableBytes());
            ctx.writeAndFlush(httpResponse);
        }
    }
}

使用浏览器进行访问：