Netty HTTP服务

1) 实例要求： 使用 IDEA 创建 Netty 项目
2) Netty 服务器在 6668 端口监听， 浏览器发出请求 "http://localhost:6668/ "
3) 服务器可以回复消息给客户端 "Hello! 我是服务器 5 " , 并对特定请求资源进行过滤.
4) 目的： Netty 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.

TestHttpServerHandler

package com.atguigu.netty.http;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.*;
import io.netty.util.CharsetUtil;

import java.net.URI;

/*
说明
1. SimpleChannelInboundHandler 是 ChannelInboundHandlerAdapter
2. HttpObject 客户端和服务器端相互通讯的数据被封装成 HttpObject
 */
public class TestHttpServerHandler extends SimpleChannelInboundHandler<HttpObject> {


    //channelRead0 读取客户端数据
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception {


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

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

        //判断 msg 是不是 httprequest请求
        if(msg instanceof HttpRequest) {

            System.out.println("ctx 类型="+ctx.getClass());

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

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

            //获取到
            HttpRequest httpRequest = (HttpRequest) msg;
            //获取uri, 过滤指定的资源
            URI uri = new URI(httpRequest.uri());
            if("/favicon.ico".equals(uri.getPath())) {
                System.out.println("请求了 favicon.ico, 不做响应");
                return;
            }
            //回复信息给浏览器 [http协议]

            ByteBuf content = Unpooled.copiedBuffer("hello, 我是服务器", CharsetUtil.UTF_8);

            //构造一个http的相应，即 httpresponse
            FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, content);

            response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain");
            response.headers().set(HttpHeaderNames.CONTENT_LENGTH, content.readableBytes());

            //将构建好 response返回
            ctx.writeAndFlush(response);

        }
    }



}

 TestServer

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;

public class TestServer {
    public static void main(String[] args) throws Exception {

        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();

            serverBootstrap.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class).childHandler(new TestServerInitializer());

            ChannelFuture channelFuture = serverBootstrap.bind(6668).sync();
            
            channelFuture.channel().closeFuture().sync();

        }finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

TestServerInitializer

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpServerCodec;


public class TestServerInitializer extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel ch) throws Exception {

        //向管道加入处理器

        //得到管道
        ChannelPipeline pipeline = ch.pipeline();

        //加入一个netty 提供的httpServerCodec codec =>[coder - decoder]
        //HttpServerCodec 说明
        //1. HttpServerCodec 是netty 提供的处理http的 编-解码器
        pipeline.addLast("MyHttpServerCodec",new HttpServerCodec());
        //2. 增加一个自定义的handler
        pipeline.addLast("MyTestHttpServerHandler", new TestHttpServerHandler());

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

    }
}