12-Netty 高性能架构设计-基于Netty开发HTTP服务

快速入门实例-HTTP 服务

1. 1. 
      
2. D实例要求：使用IDEA创建Netty项目
3. Netty服务器在6668端口监听，浏览器发出请求“​​http://localhost:6668/​​
   1. 
      
      
4. 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
5. 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

新建HttpServer

package com.dance.netty.netty.http;

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

/**
 * HTTP 服务器
 */
public class HttpServer {

    public static void main(String[] args) {

        NioEventLoopGroup boosGroup = new NioEventLoopGroup();
        NioEventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();

            serverBootstrap.group(boosGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new HttpServerInitializer());

            ChannelFuture sync = serverBootstrap.bind("127.0.0.1",80).sync();

            sync.channel().closeFuture().sync();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            boosGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }

    }

}

新建HttpServerInitializer

package com.dance.netty.netty.http;

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

/**
 * 通道初始化
 */
public class HttpServerInitializer extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel socketChannel) throws Exception {
        // 向管道加入处理器
        ChannelPipeline pipeline = socketChannel.pipeline();
        // 加入一个Netty提供的 HttpServerCodec codec => [coder - decoder]
        /*
        HttpServerCodec 是Netty提供的处理HTTP的
         */
        pipeline.addLast("MyHttpServer", new HttpServerCodec());

        // 添加自己的处理器
        pipeline.addLast("MyHandler", new HttpServerHandler());
    }
}

新建HttpServerHandler

package com.dance.netty.netty.http;

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

import java.nio.charset.StandardCharsets;

/**
 * 管道处理器
 * SimpleChannelInboundHandler 继承了 ChannelInboundHandlerAdapter
 * HttpObject 客户端和服务器相互通讯的数据定义
 */
public class HttpServerHandler extends SimpleChannelInboundHandler<HttpObject> {


    /**
     * 读取客户端数据
     * @param channelHandlerContext 上下文对象
     * @param msg httpObject对象
     * @throws Exception 异常
     */
    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, HttpObject msg) throws Exception {
        // 判断是不是HttpRequest
        if(msg instanceof HttpRequest){
            System.out.println("msg type is " + msg.getClass());
            System.out.println("client address is " + channelHandlerContext.channel().remoteAddress());

            // 回复信息给浏览器 [HTTP协议]
            ByteBuf byteBuf = Unpooled.copiedBuffer("Hello 我是服务器~", StandardCharsets.UTF_8);

            // 构造一个HTTP的响应, 即 HttpResponse
            DefaultFullHttpResponse httpResponse = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, byteBuf);

            // 设置响应信息
            httpResponse.headers()
                    .set(HttpHeaderNames.CONTENT_TYPE, "text/plain;Charset=UTF-8")
                    .set(HttpHeaderNames.CONTENT_LENGTH, byteBuf.readableBytes());

            channelHandlerContext.writeAndFlush(httpResponse);
        }
    }
}

测试

这里存在一个问题,那就是端口问题,之前是6668 chrome 访问直接被阻止

还有就是,在返回的类型中需要设置字符编码.不然会乱码

// 设置响应信息
httpResponse.headers()
    .set(HttpHeaderNames.CONTENT_TYPE, "text/plain;Charset=UTF-8")
    .set(HttpHeaderNames.CONTENT_LENGTH, byteBuf.readableBytes());

但是还是有一个问题的, 我访问了一次,但是控制台却显示的是两次

原因是应为在浏览器加载资源 的时候,同时请求了页面浏览器角标

就是这个东西

修改HttpServerHandler

package com.dance.netty.netty.http;

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

import java.nio.charset.StandardCharsets;

/**
 * 管道处理器
 * SimpleChannelInboundHandler 继承了 ChannelInboundHandlerAdapter
 * HttpObject 客户端和服务器相互通讯的数据定义
 */
public class HttpServerHandler extends SimpleChannelInboundHandler<HttpObject> {


    /**
     * 读取客户端数据
     * @param channelHandlerContext 上下文对象
     * @param msg httpObject对象
     * @throws Exception 异常
     */
    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, HttpObject msg) throws Exception {
        // 判断是不是HttpRequest
        if(msg instanceof HttpRequest){

            // 进行资源过滤
            String uri = ((HttpRequest) msg).uri();
            // 如果是图标直接结束
            if(uri.endsWith("favicon.ico")){
                System.out.println("request is favicon.ico, no result");
                return;
            }

            .............
        }
    }
}

重启后测试

可以看到角标被过滤了