Netty构建Http服务器

时间：2021-06-29 01:52:32

　　Netty 是一个基于 JAVA NIO 类库的异步通信框架，它的架构特点是：异步非阻塞、基于事件驱动、高性能、高可靠性和高可定制性。换句话说，Netty是一个NIO框架，使用它可以简单快速地开发网络应用程序，比如客户端和服务端的协议。Netty大大简化了网络程序的开发过程比如TCP和UDP的 Socket的开发。Netty 已逐渐成为 Java NIO 编程的首选框架，Netty中，通讯的双方建立连接后，会把数据按照ByteBuf的方式进行传输，因此我们在构建Http服务器的时候就是通过HttpRequestDecoder对ByteBuf数据流进行处理，转换成http的对象。代码如下：

maven依赖

<dependency>

    <groupId>io.netty</groupId>

    <artifactId>netty-all</artifactId>

    <version>4.1.0.Final</version>

</dependency>

HttpServer类

package com.example.demo.netty;

import io.netty.bootstrap.ServerBootstrap;

import io.netty.channel.ChannelFuture;

import io.netty.channel.ChannelInitializer;

import io.netty.channel.ChannelPipeline;

import io.netty.channel.EventLoopGroup;

import io.netty.channel.nio.NioEventLoopGroup;

import io.netty.channel.socket.SocketChannel;

import io.netty.channel.socket.nio.NioServerSocketChannel;

import io.netty.handler.codec.http.HttpServerCodec;

public class HttpServer {

    public static void main(String[] args) throws InterruptedException {

        EventLoopGroup bossGroup = new NioEventLoopGroup();

        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {

            ServerBootstrap b = new ServerBootstrap();

            b.group(bossGroup, workerGroup)

                    .channel(NioServerSocketChannel.class)

                    .childHandler(new ChannelInitializer<SocketChannel>() {

                        @Override

                        public void initChannel(SocketChannel ch) throws Exception {

                            ChannelPipeline pipeline = ch.pipeline();

                            pipeline.addLast(new HttpServerCodec());

                            pipeline.addLast(new HttpServerHandler());

                        }

                    });

            ChannelFuture f = b.bind(8080).sync();

            f.channel().closeFuture().sync();

        } finally {

            workerGroup.shutdownGracefully();

            bossGroup.shutdownGracefully();

        }

    }

}

HttpServerHandler类

package com.example.demo.netty;

import java.io.UnsupportedEncodingException;

import io.netty.buffer.Unpooled;

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.ChannelInboundHandlerAdapter;

import io.netty.handler.codec.http.DefaultFullHttpResponse;

import io.netty.handler.codec.http.FullHttpResponse;

import io.netty.handler.codec.http.HttpRequest;

import io.netty.handler.codec.http.HttpResponseStatus;

import io.netty.handler.codec.http.HttpVersion;

import io.netty.handler.codec.http.QueryStringDecoder;

class HttpServerHandler extends ChannelInboundHandlerAdapter {

    @Override

    public void channelRead(ChannelHandlerContext ctx, Object msg) throws UnsupportedEncodingException {

        if (msg instanceof HttpRequest) {

            // 请求，解码器将请求转换成HttpRequest对象

            HttpRequest request = (HttpRequest) msg;

            // 获取请求参数

            QueryStringDecoder queryStringDecoder = new QueryStringDecoder(request.uri());

            String name = "netty";

            if(queryStringDecoder.parameters().get("name") != null) {

                    name = queryStringDecoder.parameters().get("name").get(0);

            }

            // 响应HTML

            String responseHtml = "<html><body>Hello, " + name + "</body></html>";

            byte[] responseBytes = responseHtml.getBytes("UTF-8");

            int contentLength = responseBytes.length;

            // 构造FullHttpResponse对象，FullHttpResponse包含message body

            FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, Unpooled.wrappedBuffer(responseBytes));

            response.headers().set("Content-Type", "text/html; charset=utf-8");

            response.headers().set("Content-Length", Integer.toString(contentLength));

            ctx.writeAndFlush(response);

        }

    }

    @Override

    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {

        cause.printStackTrace();

        ctx.close();

    }

}

运行HttpServer中main方法，启动httpServer，打开浏览器输入http://localhost:8080?name=zhangsan ，结果如下：

Netty构建Http服务器

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