具体原理解析：

https://blog.csdn.net/xiangzhihong8/article/details/52029446/

1、request的流程处理

1.1 实现：

   只需要在netty的pipeLine中配置HttpRequestDecoder和HttpObjectAggregator。

1.2 原理：

•   1：如果把解析这块理解是一个黑盒的话，则输入是ByteBuf，输出是FullHttpRequest。通过该对象便可获取到所有与http协议有关的信息。
•    2：HttpRequestDecoder先通过RequestLine和Header解析成HttpRequest对象，传入到HttpObjectAggregator。然后再通过body解析出httpContent对象，传入到HttpObjectAggregator。当HttpObjectAggregator发现是LastHttpContent，则代表http协议解析完成，封装FullHttpRequest。
•    3：对于body内容的读取涉及到Content-Length和trunked两种方式。两种方式只是在解析协议时处理的不一致，最终输出是一致的。

2 response的流程处理

2.1实现

   只需要在netty的pipeLine中配置HttpResponseEncoder 

2.2原理

•      1：输入是FullHttpResponse对象，输出是ByteBuf。socket再将ByteBuf数据发送到访问端。
•      2：对FullHttpResponse按照http协议进行序列化。判断header里面是ContentLength还是Trunked，然后body按照相应的协议进行序列化。 
•      3：具体原理和request请求方式比较类似，这次不再详细描述。  

3 netty http服务器代码展示

3.1 server

package com.suirui.http;import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
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.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.stream.ChunkedWriteHandler;import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;/*** Created by zongx on 2019/12/26.*/
public class HttpServer {// 工作线程池，http消息处理都由这个线程池进行ExecutorService httpExecutor = Executors.newFixedThreadPool(8);public static void main(String[] args) {int port ;if (args != null && args.length > 0) {port = Integer.valueOf(args[0]);} else {port = 8090;}System.out.println(port);new HttpServer().bind(port);}public void bind(int port) {//配置服务端的NIO线程组//两个线程组的原因是：// 一个用于服务端接收客户端连接//一个用于进行socketChannel网络读写NioEventLoopGroup bossGroup = new NioEventLoopGroup();NioEventLoopGroup workerGroup = new NioEventLoopGroup();//ServerBootstrap 是netty的辅助启动类ServerBootstrap b = new ServerBootstrap();// .group传入两个线程组// .channel设置创建的Channel类型为NioServerSocketChannel// .option 配置NioServerSocketChannel的TCP参数// .childHandler绑定IO事件的处理类 类似reactor模式中的handler:进行连接与读写socket。// ChildChannelHandler会重写initChannel，保证当创建NioServerSocketChannel成功之后，再进行初始化。/*************.handler 与   .childHandler的区别*******/// handler()和childHandler()的主要区别是，handler()是发生在初始化的时候，childHandler()是发生在客户端连接之后。b.group(bossGroup,workerGroup).channel(NioServerSocketChannel.class).option(ChannelOption.SO_BACKLOG, 1024).childOption(ChannelOption.SO_KEEPALIVE, true).childHandler(new ChildChannelHandler());//绑定端口，等待成功try {//.sync()是同步阻塞接口，等待绑定操作完成//ChannelFuture主要用于异步操作的通知回调ChannelFuture f = b.bind(port).sync();//等待服务端监听端口关闭f.channel().closeFuture().sync();} catch (InterruptedException e) {e.printStackTrace();}finally {//释放线程池资源bossGroup.shutdownGracefully();workerGroup.shutdownGracefully();}}private class ChildChannelHandler extends ChannelInitializer<SocketChannel> {//注意此处不要使用ServerSocketChannel，否则客户端无法启动端口@Overrideprotected void initChannel(SocketChannel ch) throws Exception {//继承了ChannelHandlerAppender，并且创建了一个HttpRequestDecode和一个HttpResponseEncoderch.pipeline().addLast(new HttpServerCodec());// 目的是将多个消息转换为单一的request或者response对象,参数为聚合后http请求的大小线程ch.pipeline().addLast(new HttpObjectAggregator(64 * 1024));//目的是支持异步大文件传输（）ch.pipeline().addLast(new ChunkedWriteHandler());//业务逻辑ch.pipeline().addLast(new HttpServerRequestHandler(httpExecutor,"/http/"));}}
}

3.2 业务逻辑handler

package com.suirui.http;import com.alibaba.fastjson.JSONObject;
import com.suirui.http.controller.HttpHandlerThread;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.HttpHeaders;
import org.apache.log4j.Logger;import java.util.concurrent.ExecutorService;/*** Created by zongx on 2019/12/31.*/
public class HttpServerRequestHandler extends SimpleChannelInboundHandler<FullHttpRequest> {private static Logger logger = Logger.getLogger(HttpServerRequestHandler.class);private final String httpPrefix;private ExecutorService httpExecutors;public HttpServerRequestHandler(ExecutorService httpExecutors, String httpPrefix) {this.httpPrefix = httpPrefix;this.httpExecutors = httpExecutors;}@Overrideprotected void channelRead0(ChannelHandlerContext ctx, FullHttpRequest msg) throws Exception {String uri = msg.getUri();//判断前端来的url路径是否正确if (uri.startsWith(httpPrefix)) {JSONObject json = new JSONObject();json.put("code", 200);json.put("message", "操作成功");//获取要进行的操作与json参数int index = uri.indexOf("?");String op = uri.substring(httpPrefix.length(), index == -1 ? uri.length() : index);String param = (index == -1) ? "" : uri.substring(index + 1);String body = "";//获取请求体int len = msg.content().readableBytes();if (len > 0) {byte[] content = new byte[len];msg.content().readBytes(content);body = new String(content, "UTF-8");}//通过多线程线程池将处理结果返还HttpHandlerThread t = new HttpHandlerThread(msg.getProtocolVersion(),HttpHeaders.isKeepAlive(msg),ctx.channel(),param,body,op);httpExecutors.execute(t);}}
}