Netty剖析之Http服务案例

怼烎@ 2023-07-03 06:15 46阅读 0赞

### 前言 ###

前面我们讲了Netty的线程模型，还有一些Netty的特性，以及使用Netty编写过一个Tcp服务案例，本次呢，我们将结合前面所学的知识，来编写一个Http服务案例

### Http服务案例 ###

需求：使用Netty编写一个Http服务端，可以让浏览器正常访问，并且服务端可以返回信息给浏览器。

服务端代码基本与前面的TCP服务一致，只是在pipeline管道里额外加入了处理http的编码、解码器（HttpServerCodec），自定义的handler不在继承ChannelInboundHandlerAdapter，而是继承SimpleChannelInboundHandler，详见如下代码：

public class HttpServer {
        public static void main(String[] args) throws Exception{
    
            EventLoopGroup bossGroup = new NioEventLoopGroup();
            EventLoopGroup workerGroup = new NioEventLoopGroup();
    
            try {
    
                ServerBootstrap serverBootstrap = new ServerBootstrap();
                serverBootstrap.group(bossGroup,workerGroup)
                        .channel(NioServerSocketChannel.class)
                        .childHandler(new ChannelInitializer<SocketChannel>() {
                            @Override
                            protected void initChannel(SocketChannel socketChannel) throws Exception {
                                // 获取管道对象
                                ChannelPipeline pipeline = socketChannel.pipeline();
                                // 添加netty提供的处理http的编码、解码器
                                pipeline.addLast(new HttpServerCodec());
                                // 加入自定义的handler
                                pipeline.addLast(new HttpServerHandler());
                            }
                        });
    
                ChannelFuture channelFuture = serverBootstrap.bind(8899).sync();
                channelFuture.channel().closeFuture().sync();
            } finally {
                bossGroup.shutdownGracefully();
                workerGroup.shutdownGracefully();
            }
        }
    }

public class HttpServerHandler extends SimpleChannelInboundHandler<HttpObject> {
    
        @Override
        protected void channelRead0(ChannelHandlerContext channelHandlerContext, HttpObject httpObject) throws Exception {
            // 判断是不是Http请求
            if(httpObject instanceof HttpRequest){
    
                // 得到http请求
                HttpRequest httpRequest = (HttpRequest) httpObject;
                // 请求地址信息
                URI uri = new URI(httpRequest.uri());
                System.out.println("request url ：" + uri.getPath());
    
                ByteBuf content = Unpooled.copiedBuffer("hello client", CharsetUtil.UTF_8);
                // 创建http响应对象
                DefaultFullHttpResponse httpResponse = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, content);
                // 设置响应头
                httpResponse.headers().set(HttpHeaderNames.CONTENT_TYPE,"text/plan");
                httpResponse.headers().set(HttpHeaderNames.CONTENT_LENGTH, content.readableBytes());
    
                channelHandlerContext.writeAndFlush(httpResponse);
            }
        }
    }

浏览器访问测试：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5fY2hhbmd5aW5n_size_16_color_FFFFFF_t_70]  
可以看到，浏览器请求成功了，并且收到了服务端响应的信息。

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5fY2hhbmd5aW5n_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200203122306255.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5fY2hhbmd5aW5n,size_16,color_FFFFFF,t_70