Netty高级进阶之基于Netty的HTTP服务器开发

本通过实战演练，学习了如何基于Netty开发一个HTTP服务器。

Netty的HTTP协议栈可靠性高，性能优异。相对于传统的Tomcat、Jetty等服务器，它更加轻量级和小巧，灵活性和定制型也更好。

1. Netty服务器在8080端口监听
2. 浏览器发出请求”http://localhost:8080“
3. 服务器回复消息给客户端”你好，我是Netty服务器“，并对特定请求资源进行过滤

1. NettyHttpServer

   public class NettyHttpServer {
       private int port;
   
       public NettyHttpServer(int port) {
           this.port = port;
       }
   
       public void run() throws InterruptedException {
           NioEventLoopGroup bossGroup = null;
           NioEventLoopGroup workerGroup = null;
           try {
               // 1. 创建bossGroup线程组: 处理网络事件--连接事件，默认是2*处理器线程数目
               bossGroup = new NioEventLoopGroup(1);
               // 2. 创建workerGroup线程组: 处理网络事件--读写事件,默认是2*处理器线程数目
               workerGroup = new NioEventLoopGroup();
               // 3. 创建服务端启动助手
               ServerBootstrap serverBootstrap = new ServerBootstrap();
               // 4. 设置bossGroup线程组和workerGroup线程组
               serverBootstrap.group(bossGroup, workerGroup)
                       .channel(NioServerSocketChannel.class)
                       .option(ChannelOption.SO_BACKLOG, 128)  // 5. 设置服务端通道实现为NIO
                       .childOption(ChannelOption.SO_KEEPALIVE, Boolean.TRUE)  // 6. 参数设置，设置活跃状态，child是设置workerGroup
                       .childHandler(new ChannelInitializer() { // 7. 创建一个通道初始化对象
                           @Override
                           protected void initChannel(SocketChannel ch) throws Exception {
                               // 8. 向pipeline中添加自定义业务处理handler
                               // 自定义处理类
                               ch.pipeline().addLast(new HttpServerCodec());
                               ch.pipeline().addLast(new NettyHttpServerHandler());
                           }
                       });
               // 9. 启动服务端并绑定端口,同时将异步改为同步
               ChannelFuture channelFuture = serverBootstrap.bind(port).sync();
               System.out.println("HTTP服务器启动成功");
   
               channelFuture.addListener(new ChannelFutureListener() {
                   @Override
                   public void operationComplete(ChannelFuture future) throws Exception {
                       if (future.isSuccess()) {
                           System.out.println("端口绑定成功!");
                       } else {
                           System.out.println("端口绑定失败!");
                       }
                   }
               });
   
               // 10. 关闭通道和关闭连接池(不是真正关闭，只是设置为关闭状态)
               channelFuture.channel().closeFuture().sync();
           } finally {
               bossGroup.shutdownGracefully();
               workerGroup.shutdownGracefully();
           }
       }
   
       public static void main(String[] args) throws InterruptedException {
           new NettyHttpServer(8080).run();
       }
   }
   

2. HTTP处理类

   public class NettyHttpServerHandler extends SimpleChannelInboundHandler {
   
       
       @Override
       protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
           // 1.判断是否是HTTP请求
           if (msg instanceof HttpRequest) {
               DefaultHttpRequest request = (DefaultHttpRequest) msg;
               System.out.println("浏览器请求路径：" + request.uri());
   
               // 2.响应浏览器
               ByteBuf byteBuf = Unpooled.copiedBuffer("你好，我是Netty服务端", CharsetUtil.UTF_8);
               DefaultFullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, byteBuf);
               response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html;charset=utf-8");
               response.headers().set(HttpHeaderNames.CONTENT_LENGTH, byteBuf.readableBytes());
   
               ctx.writeAndFlush(response);
           }
       }
   }
   

3. 运行效果

4. 过滤掉图标

   // 图标不响应
   if("/favicon.ico".equals(request.uri())){
       System.out.println("图标不处理");
       return;
   }
   

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