netty编程之实现HTTP服务

news2024/12/23 10:58:06

写在前面

http是应用层协议，是我们日常开发中直接用到最多的协议了。本文来看下通过netty如何实现。

1：程序

netty不仅仅提供了String相关的编解码器，还贴心的提供了http相关的编码器和解码器，直接拿来用就行了，所以使用netty来实现http服务还是比较简单的。

1.1：server

server main:

package com.dahuyuo.netty.httpserver.server;

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

public class NettyServer {

    public static void main(String[] args) {
        new NettyServer().bing(7397);
    }

    private void bing(int port) {
        //配置服务端NIO线程组
        EventLoopGroup parentGroup = new NioEventLoopGroup(); //NioEventLoopGroup extends MultithreadEventLoopGroup Math.max(1, SystemPropertyUtil.getInt("io.netty.eventLoopThreads", NettyRuntime.availableProcessors() * 2));
        EventLoopGroup childGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(parentGroup, childGroup)
                    .channel(NioServerSocketChannel.class)    //非阻塞模式
                    .option(ChannelOption.SO_BACKLOG, 128)
                    .childOption(ChannelOption.SO_KEEPALIVE, true)
                    .childHandler(new MyChannelInitializer());
            ChannelFuture f = b.bind(port).sync();
            System.out.println("netty http server start done on port: " + 7397);
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            childGroup.shutdownGracefully();
            parentGroup.shutdownGracefully();
        }

    }

}

MyChannelInitializer:

package com.dahuyuo.netty.httpserver.server;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.LineBasedFrameDecoder;
import io.netty.handler.codec.http.HttpRequestDecoder;
import io.netty.handler.codec.http.HttpResponseEncoder;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

import java.nio.charset.Charset;

public class MyChannelInitializer extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel channel) {
        // 数据解码操作
        channel.pipeline().addLast(new HttpResponseEncoder());
        // 数据编码操作
        channel.pipeline().addLast(new HttpRequestDecoder());
        // 在管道中添加我们自己的接收数据实现方法
        channel.pipeline().addLast(new MyServerHandler());
    }

}

HttpResponseEncoder,HttpRequestDecoder就是http响应和请求和编码器和解码器。MyServerHandler是自定义的inbound的消息处理器：

package com.dahuyuo.netty.httpserver.server;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.EmptyByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.*;

import java.nio.charset.Charset;
import java.text.SimpleDateFormat;
import java.util.Date;

public class MyServerHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {

        if (msg instanceof HttpRequest) {
            DefaultHttpRequest request = (DefaultHttpRequest) msg;
            System.out.println("URI:" + request.getUri());
            System.err.println(msg);
        }

        if (msg instanceof HttpContent) {
            LastHttpContent httpContent = (LastHttpContent) msg;
            ByteBuf byteData = httpContent.content();
            if (!(byteData instanceof EmptyByteBuf)) {
                //接收msg消息
                byte[] msgByte = new byte[byteData.readableBytes()];
                byteData.readBytes(msgByte);
                System.out.println(new String(msgByte, Charset.forName("UTF-8")));
            }
        }

        String sendMsg = "我是netty实现的http server响应的内容啊！！！";

        FullHttpResponse response = new DefaultFullHttpResponse(
                HttpVersion.HTTP_1_1,
                HttpResponseStatus.OK,
                Unpooled.wrappedBuffer(sendMsg.getBytes(Charset.forName("UTF-8"))));
        response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain;charset=UTF-8");
        response.headers().set(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
        response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE);
        ctx.write(response);
        ctx.flush();
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        ctx.close();
        cause.printStackTrace();
    }

}