【netty】实现http服务

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发布于 2022-05-30 00:43:55

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代码可运行

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代码可运行

学习netty的小案例，用netty实现一个http服务。

一、需求

Netty 服务器在 8888 端口监听，浏览器发出请求 "http://localhost:8888/ "
服务器可以回复消息给客户端 "Hello! 我是服务器 " , 并对特定请求资源进行过滤.
目的：Netty 也可以做Http服务开发，并且理解Handler实例和客户端及其请求的关系

二、服务端代码

HttpNettyServer

public class HttpNettyServer {
    public static void main(String[] args) {
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workGroup = new NioEventLoopGroup(1);
        try {
            ServerBootstrap sb = new ServerBootstrap();
            sb.group(bossGroup, workGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new HttpChannelInitializer());

            ChannelFuture cf = sb.bind(8888).sync();
            cf.addListener(future -> {
                if (future.isSuccess()) {
                    System.out.println("http is ready");
                }
            });
            cf.channel().closeFuture().sync();

        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            bossGroup.shutdownGracefully();
            workGroup.shutdownGracefully();
        }
    }
}

HttpChannelInitializer

public class HttpChannelInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel ch) {
        // 向管道加入处理器
        // 获取 管道
        ChannelPipeline pipeline = ch.pipeline();
        // 加入netty 提供的 HttpSeverCodec  codec => [coder - decoder]
        // HttpSeverCodec 是 netty 提供的 处理Http 的编-解码器
        pipeline.addLast("MyHttpServerCodec", new HttpServerCodec());
        // 增加一个自定义的 handler
        pipeline.addLast("MyHttpServerHandler", new HttpServerHandler());

        System.out.println("ok~~~~");
    }
}

HttpServerHandler

public class HttpServerHandler extends SimpleChannelInboundHandler<HttpObject> {
    // 读取客户端数据
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) {

        System.out.println("1对应的channel=" + ctx.channel() + ",pipeline=" + ctx
                .pipeline() + " 通过pipeline获取channel" + ctx.pipeline().channel());

        System.out.println("2当前ctx的handler=" + ctx.handler());

        System.out.println("3msg类型：" + msg.getClass());
        System.out.println("4客户端地址：" + ctx.channel().remoteAddress());

        // 回复信息给浏览器[Http 协议]
        if (msg instanceof HttpRequest) {

            System.out.println("5ctx 类型=" + ctx.getClass());
            System.out.println("6pipeline hashcode" + ctx.pipeline().hashCode() + " TestHttpServerHandler hash=" + this.hashCode());

            HttpRequest request = (HttpRequest) msg;
            // 获取Uri，过滤指定的资源
            String uri = request.uri();
            System.out.println(uri);
            if (uri.contains("favicon.ico")) {
                return;
            }


            ByteBuf content = Unpooled.copiedBuffer("Hello,我是服务器", CharsetUtil.UTF_8);
            // 构造一个Http的响应，即httpResponse
            FullHttpResponse httpResponse
                    = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, content);

            httpResponse.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain;charset=utf-8");
            httpResponse.headers().set(HttpHeaderNames.CONTENT_LENGTH, content.readableBytes());

            // 返回
            ctx.writeAndFlush(httpResponse);
        }

    }
}